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June 18, 2008

https://www.sciencedaily.com/releases/2008/06/080616163421.htm

Perfecting A Solar Cell By Adding Imperfections

Nanotechnology is paving the way toward improved solar cells. New research shows that a film of carbon nanotubes may be able to replace two of the layers normally used in a solar cell, with improved performance at a lower cost. Researchers have found a surprising way to give the nanotubes the properties they need: add defects.

Currently, these solar cells, called dye-sensitized solar cells, have a transparent film made of an oxide that is applied to glass and conducts electricity. In addition, a separate film made of platinum acts as a catalyst to speed the chemical reactions involved.Both of these materials have disadvantages, though. The oxide films can't easily be applied to flexible materials: they perform much better on a rigid and heat resistant substrate like glass. This increases costs and limits the kinds of products that can be made. And expensive equipment is necessary to create the platinum films.Jessika Trancik of the Santa Fe Institute, Scott Calabrese Barton of Michigan State University and James Hone of Columbia University decided to use carbon nanotubes to create a single layer that could perform the functions of both the oxide and platinum layers. They needed it to have three properties: transparency, conductivity, and catalytic activity.Ordinary carbon nanotubes films are so-so in each of these properties. The obvious ways of improving one, though, sacrifice one of the others. For example, making the film thicker makes it a better catalyst, but then it's less transparent.Previous theory had suggested that materials may function better as catalysts when they have tiny defects, providing sites for chemicals to attach. So the researchers tried exposing the carbon nanotubes to ozone, which roughs them up a bit. Very thin films, they found, became dramatically better catalysts, with more than ten-fold improvement.Thin, transparent nanotube films catalyze the reduction of triiodide, a reaction important for the dye-sensitized solar cell, with a charge-transfer resistance as measured by electrochemical impedance spectroscopy that decreases with increasing film thickness. Moreover the catalytic activity can be enhanced by exposing nanotubes to ozone to introduce defects. Ozone-treated, defective nanotube films could serve as catalytic, transparent, conducting electrodes for the dye-sensitized solar cell.  Other applications include batteries, fuel cells, and electroanalytical devices.In fact, the performance gets close to that of platinum. "That's remarkable," Trancik says, "because platinum is considered pretty much the best catalyst there is."In order to address the trade-off between transparency and conductivity, the researchers tried another trick on a bottom layer of tubes: they created carbon nanotubes that were longer. This improved both conductivity and transparency.The carbon nanotube films might be used in fuel cells and batteries as well."This study is an example of using nanostructuring of materials -- changing things like defect density and tube length at very small scales -- to shift trade-offs between materials properties and get more performance out of a given material," Trancik says. "Making inexpensive materials behave in advanced ways is critical for achieving low-carbon emissions and low cost energy technologies."The researchers published their results recently in Nano Letters. They are currently in the process of filing a patent application for their techniques.

Ozone Holes

June 13, 2008

https://www.sciencedaily.com/releases/2008/06/080612141015.htm

Computer Models Show Major Climate Shift As A Result Of Closing Ozone Hole

A new study led by Columbia University researchers has found that the closing of the ozone hole, which is projected to occur sometime in the second half of the 21st century, may significantly affect climate change in the Southern Hemisphere, and therefore, the global climate. The study appears in the June 13th issue of Science.

The Earth's ozone layer is located in the lower stratosphere, which lies just above the troposphere (which begins at the planet's surface and reaches up to about 12 km), catching harmful ultraviolet rays from the sun. Until late in the last century, widespread usage of household and commercial aerosols containing chlorofluorocarbons (CFC), unstable compounds which are carried into the stratosphere, lead to significant and rapid ozone depletion. Due to the Montreal Protocol, signed by 191 countries, CFC production worldwide was phased out in 1996.Observations in the last few years indicate that ozone depletion has largely halted and is expected to fully reverse. As a consequence, the new study finds, the Southern Hemisphere climate change may also reverse. This would be a very tangible outcome of the Montreal Protocol, which has been called the single most successful international agreement to date, and would demonstrate how international treaties are able to make positive changes to the climate system."Our results suggest that stratospheric ozone is important for the Southern Hemisphere climate change, and ought to be more carefully considered in the next set of IPCC model integrations," said Seok-Woo Son, lead-author of the study and a postdoctoral research scientist at Columbia's Fu Foundation School of Engineering and Applied Science (SEAS).The team of 10 scientists compared results from two sets of climate models, the first one used by the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), released in late 2007, and the second from the Scientific Assessment of Ozone Depletion, published by the World Meteorological Organization in 2006. In their prediction of future climate, many IPCC models did not consider the expected ozone recovery and its potential impacts on climate change. The chemistry-climate models used for the 2006 Ozone Assessment, however, predict that the Antarctic ozone hole will achieve full recovery in the second half of this century, and that this may have profound impacts on the surface winds and, likely, on other aspects of the Earth's climate, including surface temperatures, locations of storm tracks, extent of dry zones, amount of sea ice, and ocean circulation.In the past few decades, the tropospheric winds in the Southern Hemisphere have been accelerating closer to the planet's pole as a result of increasing greenhouse gases and decreasing ozone. This wind change has had a broad range of effects on the Earth's climate. The IPCC models predict that this effect will continue, albeit at a slower pace. In contrast, predictions made by the chemistry-climate models indicate that, as a consequence of ozone recovery--a factor largely ignored by IPCC models--the tropospheric winds in the Southern Hemisphere may actually decelerate in the high latitudes and move toward the equator, potentially reversing the direction of climate change in that hemisphere."We were surprised to find that the closing of the ozone hole, which is expected to occur in the next 50 years or so, shows significant effects on the global climate," said Lorenzo M. Polvani, one of two principle investigators and professor of applied physics and applied mathematics at SEAS. "This is because stratospheric ozone has not been considered a major player in the climate system."Polvani and Son state that more research needs to be conducted to validate their results, and to fully understand how complete ozone recovery will impact the planet's changing climate. While previous studies have shown that ozone hole recovery could lead to a warming of the Antarctic, much work remains. For instance, the chemistry-climate models used in the 2006 Ozone Assessment Report do not include a full ocean circulation, which might affect surface temperatures. The interactions between a recovering ozone hole, increasing greenhouse gases, ocean currents, and other components of the climate system must still be explored in order to better understand how the Earth's climate will change in the future.In addition to Polvani and Son, researchers from Johns Hopkins (Baltimore, MD), the National Institute for Environmental Studies (Tsukuba, Japan), the National Center for Atmospheric Research (Boulder, CO), the NASA Goddard Space Flight Center (Greenbelt, MD), the Institute for Atmospheric and Climate Sciences at ETH (Zurich, Switzerland), the Physical Meteorological Observatory (Davos, Switzerland), the University of Toronto (Toronto, Canada), and the Meteorological Research Institute (Tsukuba, Japan).

Ozone Holes

June 9, 2008

https://www.sciencedaily.com/releases/2008/06/080603183309.htm

Lower Crop Yields Due To Ozone A Factor In World Food Crisis

Heat waves, droughts and fuel prices are just a few reasons for the current global food crisis that is making headlines around the world. Research by William Manning of the University of Massachusetts Amherst indicates that rising background levels of ozone in the atmosphere are a likely contributor to the problem, lowering the yield of important food crops, such as wheat and soybeans.

“Plants are much more sensitive to ozone than people, and a slight increase in exposure can have a large impact on their productivity,” says Manning, a professor of plant, soil and insect sciences. “The new ozone standard set by the U.S. EPA in March 2008 is based on protecting human health, and may not be strict enough to protect plants.” Manning served on the Clean Air Science Advisory Committee for the EPA in 1997 when the previous air quality standard for ozone was developed.According to Manning, emission controls on cars have been successful in reducing short periods of high ozone levels called peaks, but average concentrations of ozone in the atmosphere throughout the year, called the background level, is increasing as polluted air masses from Asia travel to the U. S. and then on to Europe. Background levels are now between 20 and 45 parts per billion in Europe and the United States, and are expected to increase to between 42 and 84 parts per billion by 2100.Manning was recently part of a team of researchers studying how ozone levels in the Yangtze Delta affect the growth of oilseed rape, a member of the cabbage family that produces one-third of the vegetable oil used in China. By growing the plants in chambers that controlled the ozone environment, the team showed that exposure to elevated ozone reduced the size and weight, or biomass, of the plants by 10 to 20 percent. Production of seeds and oil was also reduced. Results of the study are scheduled for publication in Environmental Pollution.“What was surprising about this research was that plants exposed to ozone levels that peaked in the late afternoon suffered more damage than plants exposed to a steady ozone concentration throughout the day, even though average ozone concentrations were the same for both groups,” says Manning. “This shows that current ozone standards that rely on average concentrations would underestimate crop losses.”Additional research in the Yangtze Valley, which accounts for nearly half of China’s crop production, showed that wheat was more sensitive to ozone than rice. “Plants vary widely in their sensitivity to ozone, and varieties of the same species can react differently,” says Manning. “Some of the most sensitive plant species are from the legume and cabbage families, which include radishes, broccoli and soybeans.”Plants can limit ozone damage for short periods of time by reducing the size of pores on their leaves called stomata. This reduces the uptake of ozone, but also carbon dioxide, which is used as the plants make food through the process of photosynthesis. Chronic exposure results in reduced photosynthesis, plant growth and yields. In the long term, leaf injury occurs when the amount of ozone taken in exceeds the leaf’s capacity to provide antioxidants to counter its effects.This summer, Manning will be investigating the effects of ozone on a variety of plants in the Pioneer Valley of Massachusetts, where ozone levels are often above the EPA standard as pollution from New York City and Washington, D.C. moves northward during the day. Plants will be grown in open fields, and some will be treated with a compound that blocks the effects of ozone. If the treated plants are healthier than the untreated group, then ozone will be the cause.

Ozone Holes

June 2, 2008

https://www.sciencedaily.com/releases/2008/05/080529162856.htm

Even Low Levels Of Air Pollution May Pose Stroke Risk

A new study investigated the association between short-term exposure to ambient fine particulate matter and the risk of stroke and found that even low pollutant levels may increase that risk. 

Led by Dr. Lynda Lisabeth of the University of Michigan School of Public Health and University of Michigan Stroke Program, researchers studied the effects of air pollution in a southeast Texas community where there is a large petroleum and petrochemical industry presence. They identified ischemic strokes and transient ischemic attacks (TIAs) from the Brain Attack Surveillance in Corpus Christi Project (BASIC), a population-based stroke surveillance project designed to capture all strokes in Nueces County, TX.Ischemic stroke and TIA cases between 2001 and 2005 were identified using trained staff and later verified by neurologists. Daily historical air pollutant and meteorological data were obtained for the same time period from the Texas Commission on Environmental Quality’s Monitoring Operations database. Data on fine particulate matter and ozone were available from a centrally located monitor in Corpus Christi ( Nueces County, TX) located upwind of the local industrial facilities. The majority of stroke/TIA cases were also located upwind of local chemical plants and refineries.The results showed borderline significant associations between same day and previous day fine particulate matter exposures and ischemic stroke/TIA risk. Similar associations were seen with ozone. Despite the fossil fuel industry in the area, fine particulate matter exposures were relatively low relative to other regions in the US, probably because of the proximity to the coast and prevailing wind patterns. “Although the magnitude of elevated risk of stroke/TIA due to PM2.5 exposure was relatively small, the vast majority of the public is exposed to ambient air pollution at the levels observed in this community or greater every day, suggesting a potentially large public health impact.”These findings support the hypotheses that recent exposure to fine particulate matter may increase the risk of ischemic cerebrovascular events specifically. There is experimental evidence that particulate air pollution is associated with acute artery vasoconstriction and with increases in plasma viscosity (thickening of the blood) which may enhance the potential for blood clots, although this requires further study.“While our observed association between PM2.5 and stroke/TIA risk requires further study in additional regions in the US with varying types of climates and possibly with alternative study designs, it does call into question current standards for fine particulate matter and whether these standards are sufficient to protect the public with regard to stroke, our nation’s third leading cause of death,” the authors note. Although the study focused on fine particulate matter, the association of ozone levels and stroke/TIA risk suggests that ambient air pollution in general may affect stroke risk.

Ozone Holes

May 18, 2008

https://www.sciencedaily.com/releases/2008/05/080515145419.htm

Excessive Reactive Nitrogen in Environment Alarms Environmental Scientists

While human-caused global climate change has long been a concern for environmental scientists and is a well-known public policy issue, the problem of excessive reactive nitrogen in the environment is little-known beyond a growing circle of environmental scientists who study how the element cycles through the environment and negatively alters local and global ecosystems and potentially harms human health.

Two new papers by leading environmental scientists bring the problem to the forefront in the May 16 issue of the journal Science. The researchers discuss how food and energy production are causing reactive nitrogen to accumulate in soil, water, the atmosphere and coastal oceanic waters, contributing to the greenhouse effect, smog, haze, acid rain, coastal "dead zones" and stratospheric ozone depletion."The public does not yet know much about nitrogen, but in many ways it is as big an issue as carbon, and due to the interactions of nitrogen and carbon, makes the challenge of providing food and energy to the world's peoples without harming the global environment a tremendous challenge," said University of Virginia environmental sciences professor James Galloway, the lead author of one of the Science papers and a co-author on the other. "We are accumulating reactive nitrogen in the environment at alarming rates, and this may prove to be as serious as putting carbon dioxide in the atmosphere."Galloway, the founding chair of the International Nitrogen Initiative, and a co-winner of the 2008 Tyler Prize for environmental science, is a longtime contributor to the growing understanding of how nitrogen cycles endlessly through the environment. In numerous studies over the years he has come to the realization of the "nitrogen cascade." In its inert form, nitrogen is harmless and abundant, making up 78 percent of the Earth's atmosphere. But in the past century, with the mass production of nitrogen-based fertilizers and the large-scale burning of fossil fuels, massive amounts of reactive nitrogen compounds, such as ammonia, have entered the environment."A unique and troublesome aspect of nitrogen is that a single atom released to the environment can cause a cascading sequence of events, resulting ultimately in harm to the natural balance of our ecosystems and to our very health," Galloway said.A nitrogen atom that starts out as part of a smog-forming compound may be deposited in lakes and forests as nitric acid, which can kill fish and insects. Carried out to the coast, the same nitrogen atom may contribute to red tides and dead zones. Finally, the nitrogen will be put back into the atmosphere as part of the greenhouse gas nitrous oxide, which destroys atmospheric ozone.Galloway and his colleagues suggest possible approaches to minimizing nitrogen use, such as optimizing its uptake by plants and animals, recovering and reusing nitrogen from manure and sewage, and decreasing nitrogen emissions from fossil fuel combustion."Nitrogen is needed to grow food," Galloway says, "but because of the inefficiencies of nitrogen uptake by plants and animals, only about 10 to 15 percent of reactive nitrogen ever enters a human mouth as food. The rest is lost to the environment and injected into the atmosphere by combustion."We must soon begin to manage nitrogen use in an integrated manner by decreasing our rate of creation of reactive nitrogen while continuing to produce enough food and energy to sustain a growing world population."Galloway's next effort is to create a "nitrogen footprint" calculator that people can access on the Internet, very similar to current "carbon footprint" calculators.He says people can reduce their nitrogen footprints by reducing energy consumption at home, traveling less, and changing diet to locally grown vegetables (preferably organic) and fish and consuming less meat.Galloway is quick to point out that along with the problems of excess reactive nitrogen in many areas of the world, there also are large regions, such as Africa, with too little nitrogen to grow enough food for rapidly growing populations. In those regions, the challenge is find ways to increase the availability of nitrogen while minimizing the negative environmental effects of too much nitrogen.

Ozone Holes

May 15, 2008

https://www.sciencedaily.com/releases/2008/05/080514143344.htm

Chemistry Of Airborne Particulate: Lung Interactions Revealed

Exactly how airborne particulates harm our lungs still puzzles epidemiologists, physicians, environmental scientists, and policy makers. Now California Institute of Technology researchers have found that they act by impairing the lungs' natural defenses against ozone.

"I've long been perplexed by the inconclusive debates, based on epidemiological and clinical evidence, over whether the causative agent is particle size or some unspecified chemical component. I always felt that some missing chemistry might be associated with particle effects," says A. J. Colussi, a senior research associate in environmental science and engineering at Caltech and author of the study.The researchers harnessed breakthroughs in chemistry to focus on what happens when air meets the thin layer of antioxidant-rich fluid that covers our lungs, protecting them from ozone, an air pollutant that pervades major cities. "We found new chemistry at the interfaces separating gases from liquids using a technique that continuously monitors the composition of these interfaces," Colussi says.Adapting an innovation in mass spectrometry by Nobel laureate John Fenn of Virginia Commonwealth University, the Caltech team studied how aqueous ascorbic acid, the essential antioxidant also known as vitamin C and present in lungs' fluid layer, reacts with ozone gas.Under normal physiological conditions, ascorbic acid instantly scavenges ozone, generating innocuous byproducts. However, the researchers discovered that when the fluid is acidic--a pathological condition found in asthmatics--ascorbic acid instead reacts with ozone to form potentially harmful compounds called ozonides."I immediately wondered whether ozonides would injure living tissues," Colussi comments. Indeed, he found literature reports that an ozonide is the active component of a plant extract used in Chinese medicine 2,500 years ago to treat malaria. Synthetic ozonide surrogates are currently used to target the malaria parasite: when the parasite disrupts red blood cells, the reduced iron that is released converts ozonides into cytotoxic free radicals on the spot. The nearby cells that the free radicals damage include the parasite.The Caltech researchers inferred that inhalation of fine airborne particulates is an essential cofactor for ozonide production. The finer a particle is, the more acidic it is, so when particles are inhaled, they lower the lung pH. Most particulates also carry iron. In the lungs, then, the particularly harmful combination of ascorbic acid, ozone, low pH, and iron should trigger an acute inflammatory response.To study the conditions that create ozonides, the team conducted experiments in which ascorbic acid solutions are sprayed, converting the liquid into fine droplets. When this mist is crossed by a stream of ozone gas, reactions at the interface of liquid and gas create products that are ultimately ejected from the droplets and then identified by a mass spectrometer.Fenn had shown why the ions detected by this technique come exclusively from the droplets' interfacial layers, Colussi says. For the Caltech team, the approach provided a means to discover that ozonide yields are markedly enhanced in an acidic setting, when pH falls below five (pH 7 is neutral), and that ozonides are produced at the gas-liquid interface but not in bulk solution."Epidemiologists had consistently found significant increases in emergency-room admissions and cardiorespiratory deaths during episodes of high levels of both atmospheric ozone and particulates in several American and European cities, and they didn't know why. Now we have a plausible hypothesis about how ozone and particulates potentiate their harmful effects synergistically," Colussi says. Indeed, the National Academies recently confirmed a link between ozone and premature death."This is a chemical breakthrough with wide implications ranging from lung physiology to environmental policy," remarks Colussi. He intends to continue the study in vivo."Our tissues, except the stomach, were designed to function at about pH 7," Colussi notes. For example, asthmatics alleviate breathing difficulties by inhaling nebulized bicarbonate solutions at pH 8 to counteract low lung pH just like Tums does for heartburn.The study appears this week in the early online edition of the Proceedings of the National Academy of Sciences. Other authors are Shinichi Enami, a postdoctoral scholar in environmental science and engineering, and Michael Hoffmann, Caltech's Irvine Professor of Environmental Science and Dean of Graduate Studies.

Ozone Holes

May 13, 2008

https://www.sciencedaily.com/releases/2008/05/080512105739.htm

Waste Water Treatment: Oxidation Of Contaminants As If They Got Burnt In The Water Itself

Reducing the level of contamination of water is the aim of the line of research being undertaken by Dr. José Ignacio Lombraña at the University of the Basque Country’s Faculty of Science and Technology. He is investigating chemical treatment capable of eliminating contaminants dumped by industry, in order to reuse the waste water.

Industrial activity is one of the principal causes of contamination in water, given that industry dumps large amounts of chemical compounds into rivers that are not capable of degrading by themselves. While most organic waste is biodegradable, others, such as plastics, colorants or detergents, ever-present in industry, stay in the water impeding its use as a resource. It was within this context that Dr. José Ignacio Lombraña led his research at the Faculty of Science and Technology of the University of the Basque Country (UPV/EHU). His goal was to find new technologies to eliminate contaminant substances dumped in water, by means of a process known as advanced oxidation. As Dr. Lombraña stated, “this involves oxidising the chemical compound – as if the substance were being burnt in the water itself”.In order for the contaminants to be oxidised in the water, the Energy and Environmental Chemical Engineering team to which Dr. Lombraña belongs, used ozone (OGiven the practical nature of the research, Dr. Lombraña takes a real problem as a starting point; for example, the presence of a contaminant that prevents using the water from a particular source. In the first place he chose three large groups of contaminants: colorants, detersive water (contaminated with detergents) and phenolics (containing phenol and derivatives). Once the compound responsible for the contamination is defined, “we construct a waste water model which facilitates its study, i.e. we create a kind of ‘synthetic water’ that contains basically the same substance as that we wish to oxidise”, explained Dr. Lombraña.One of the main achievements of this research undertaken at the UPV/EHU was precisely the defining of models for the degradation of various compounds or, as the Director of the project put it, “describing why a molecule passes through phases or states until its total degradation”. Notable amongst the oxidation techniques studied, was the FENTON reagent (a mixture of iron salts and hydrogen peroxide) and the combination of hydrogen peroxide with ultraviolet rays.The research team finally started the verification stage: “We tested the previously described degradation models in water dumped by companies in the area in order to check the efficacy of the oxidants in the destruction of these key contaminants”, pointed out Dr. Lombraña.The work of the research team at the UPV-EHU Faculty of Science and Technology was not limited to analysing and describing the oxidation processes of different contaminants. It also studied the design of the equipment required for this work. Thus, a number of ozonisation prototypes (installations for applying ozone to water) were developed, optimising the conditions for producing oxidation.Advanced oxidation is a technology which is still at the development stage and, thus, is still not usually used in water treatment plants. The aim of the research led by José Ignacio Lombraña is to contribute to the knowledge base required for this technology to be applicable, not so much at water treatment plants as at treatment plants specifically devoted to water of industrial origin. “The greatest difficulties arise when we come across test banks as companies want instant solution products and only the largest enterprises can afford the investment in pilot prototypes for their installations”, stated Dr. Lombraña.The project, entitled, New strategies in advanced oxidation technologies using ozone and hydrogen peroxide, received a grant from the Ministry of Education and Science, and falls within the remit of the overall research lines into the recovery of waste water. The team currently led by Dr. José Ignacio Lombraña has embarked on a new project coordinated by the Pyrenees Work Community and in which the Rovira i Virgili University of Tarragona and the University of Toulouse (France) are taking part.

Ozone Holes

May 8, 2008

https://www.sciencedaily.com/releases/2008/05/080507132855.htm

Climate Models Overheat Antarctica, New Study Finds

Computer analyses of global climate have consistently overstated warming in Antarctica, concludes new research by scientists at the National Center for Atmospheric Research (NCAR) and Ohio State University. The study can help scientists improve computer models and determine if Earth's southernmost continent will warm significantly this century, a major research question because of Antarctica's potential impact on global sea-level rise.

"We can now compare computer simulations with observations of actual climate trends in Antarctica," says NCAR scientist Andrew Monaghan, the lead author of the study. "This is showing us that, over the past century, most of Antarctica has not undergone the fairly dramatic warming that has affected the rest of the globe. The challenges of studying climate in this remote environment make it difficult to say what the future holds for Antarctica's climate."The study marks the first time that scientists have been able to compare records of the past 50 to 100 years of Antarctic climate with simulations run on computer models. Researchers have used atmospheric observations to confirm that computer models are accurately simulating climate for the other six continents. The models, which are mathematical representations of Earth's climate system, are a primary method for scientists to project future climate.Antarctica's climate is of worldwide interest, in part because of the enormous water locked up in its ice sheets. If those vast ice sheets were to begin to melt, sea level could rise across the globe and inundate low-lying coastal areas. Yet, whereas climate models accurately simulate the last century of warming for the rest of the world, they have unique challenges simulating Antarctic climate because of limited information about the continent's harsh weather patterns.The study was published on April 5 in Geophysical Research Letters. It was funded by the National Science Foundation, NCAR's primary sponsor, and the Department of Energy.The authors compared recently constructed temperature data sets from Antarctica, based on data from ice cores and ground weather stations, to 20th century simulations from computer models used by scientists to simulate global climate. While the observed Antarctic temperatures rose by about 0.4 degrees Fahrenheit (0.2 degrees Celsius) over the past century, the climate models simulated increases in Antarctic temperatures during the same period of 1.4 degrees F (0.75 degrees C).The error appeared to be caused by models overestimating the amount of water vapor in the Antarctic atmosphere, the new study concludes. The reason may have to do with the cold Antarctic atmosphere handling moisture differently than the atmosphere over warmer regions.Part of the reason that Antarctica has barely warmed has to do with the ozone hole over the continent. The lack of ozone is chilling the middle and upper atmosphere, altering wind patterns in a way that keeps comparatively warm air from reaching the surface. Unlike the rest of the continent, the Antarctic Peninsula has warmed by several degrees, in part because the winds there are drawing in warmer air from the north. The models generally capture these wind changes, although sometimes incompletely.The study delivered a mixed verdict on Antarctica's potential impact on sea-level rise. The Intergovernmental Panel on Climate Change, which operates under the auspices of the United Nations, has estimated that sea-level rise could amount to 7 to 23 inches (18-59 centimeters) this century, in part because of melting glaciers worldwide. The Geophysical Research Letters paper suggests that warming in Antarctica over the next century could offset that by about 2 inches if the continent warms by 5.4 degrees F (3 degrees C), as computer models have indicated. The reason is that the warmer air over Antarctica would hold more moisture and generate more snowfall, thereby locking up additional water in the continent's ice sheets.But the authors caution that model projections of future Antarctic climate may be unreliable."The research clearly shows that you can actually slow down sea-level rise when you increase temperatures over Antarctica because snowfall increases, but warmer temperatures also have the potential to speed up sea-level rise due to enhanced melting along the edges of Antarctica," says Monaghan, who did some of his research at Ohio State University before coming to NCAR. "Over the next century, whether the ice sheet grows from increased snowfall or shrinks due to more melt will depend on how much temperatures increase in Antarctica, and potentially on erosion at the ice sheet edge by the warmer ocean and rising sea level.""The current generation of climate models has improved over previous generations, but still leaves Antarctic surface temperature projections for the 21st century with a high degree of uncertainty," adds co-author and NCAR scientist David Schneider. "On a positive note, this study points out that water vapor appears to be the key cause of the problematic Antarctic temperature trends in the models, which will guide scientists as they work to improve the climate simulations."The University Corporation for Atmospheric Research manages the National Center for Atmospheric Research under primary sponsorship by the National Science Foundation (NSF). Opinions, findings, conclusions, or recommendations expressed in this document are those of the author(s) and do not necessarily reflect the views of the National Science Foundation, NASA, or other funding agencies.

Ozone Holes

May 7, 2008

https://www.sciencedaily.com/releases/2008/05/080506103036.htm

Stressed Seaweed Contributes To Cloudy Coastal Skies, Study Suggests

Scientists at The University of Manchester have helped to identify that the presence of large amounts of seaweed in coastal areas can influence the climate.

A new international study has found that large brown seaweeds, when under stress, release large quantities of inorganic iodine into the coastal atmosphere, where it may contribute to cloud formation.A scientific paper published online  May 6 2008 in the Proceedings of the National Academy of Science (PNAS) identifies that iodine is stored in the form of iodide -- single, negatively charged ions.When this iodide is released it acts as the first known inorganic -- and the most simple -- antioxidant in any living system."When kelp experience stress, for example when they are exposed to intense light, desiccation or atmospheric ozone during low tides, they very quickly begin to release large quantities of iodide from stores inside the tissues," explains lead author, Dr Frithjof Küpper from the Scottish Association for Marine Science."These ions detoxify ozone and other oxidants that could otherwise damage kelp, and, in the process, produce molecular iodine."Our new data provide a biological explanation why we can measure large amounts of iodine oxide and volatile halocarbons in the atmosphere above kelp beds and forests. These chemicals act as condensation nuclei around which clouds may form."The paper's co-author, Dr Gordon McFiggans, an atmospheric scientist from The University of Manchester's School of Earth, Atmospheric and Environmental Sciences (SEAES) said: "The findings are applicable to any coastal areas where there are extensive kelp beds. In the UK, these are typically place like the Hebrides, Robin Hood's Bay and Anglesey. The kelps need rocky intertidal zones to prosper - sandy beaches aren't very good."The increase in the number of cloud condensation nuclei may lead to 'thicker' clouds. These are optically brighter, reflecting more sunlight upwards and allowing less to reach the ground, and last for longer. In such a cloud there are a higher number of small cloud droplets and rainfall is suppressed, compared with clouds of fewer larger droplets."The increase in cloud condensation nuclei by kelps could lead to more extensive, longer lasting cloud cover in the coastal region -- a much moodier, typically British coastal skyline."The research team also found that large amounts of iodide are released from kelp tissues into sea water as a consequence to the oxidative stress during a defence response against pathogen attack. They say kelps therefore play an important role in the global biogeochemical cycle of iodine and in the removal of ozone close to the Earth's surface.This interdisciplinary and international study -- with contributions from the United Kingdom, the Netherlands, Germany, France, Switzerland, the European Molecular Biology Laboratory (EMBL) and the USA -- comes almost 200 years after the discovery of iodine as a novel element -- in kelp ashes.

Ozone Holes

April 25, 2008

https://www.sciencedaily.com/releases/2008/04/080424140407.htm

Stratospheric Injections To Counter Global Warming Could Damage Ozone Layer

A much-discussed idea to offset global warming by injecting sulfate particles into the stratosphere would have a drastic impact on Earth's protective ozone layer, new research concludes. The study, led by Simone Tilmes of the National Center for Atmospheric Research (NCAR), warns that such an approach might delay the recovery of the Antarctic ozone hole by decades and cause significant ozone loss over the Arctic.

"Our research indicates that trying to artificially cool off the planet could have perilous side effects," Tilmes says. "While climate change is a major threat, more research is required before society attempts global geoengineering solutions."In recent years, climate scientists have studied "geoengineering" proposals to cool the planet and mitigate the most severe impacts of global warming. Such plans could be in addition to efforts to reduce greenhouse gas emissions. One of the most-discussed ideas, analyzed by Nobel laureate Paul Crutzen and other researchers, would be to regularly inject large amounts of Sun-blocking sulfate particles into the stratosphere. The goal would be to cool Earth's surface, much as sulfur particles from major volcanic eruptions in the past have resulted in reduced surface temperatures.Since major volcanic eruptions temporarily thin the ozone layer in the stratosphere, Tilmes and her colleagues looked into the potential impact of geoengineering plans on ozone over the poles. Sulfates from volcanoes provide a surface on which chlorine gases in the cold polar lower stratosphere can become activated and cause chemical reactions that intensify the destruction of ozone molecules, although the sulfates themselves do not directly destroy ozone.The new study concluded that, over the next few decades, hypothetical artificial injections of sulfates likely would destroy between about one-fourth to three-fourths of the ozone layer above the Arctic. This would affect a large part of the Northern Hemisphere because of atmospheric circulation patterns. The impacts would likely be somewhat less during the second half of this century because of international agreements that have essentially banned the production of ozone-depleting chemicals.The sulfates would also delay the expected recovery of the ozone hole over the Antarctic by about 30 to 70 years, or until at least the last decade of this century, the authors conclude.Recovery of the ozone hole has been a major goal of policymakers worldwide. Nations agreed in 1987 to a landmark accord, known as the Montreal protocol, to restrict the production of industrial chemicals, known as CFCs (chlorofluorocarbons), that cause ozone-destroying chemical reactions. The ozone layer is critical for life on Earth because it blocks dangerous ultraviolet radiation from the Sun."This study highlights another connection between global warming and ozone depletion," says co-author Ross Salawitch of the University of Maryland. "These traditionally had been thought of as separate problems but are now increasingly recognized to be coupled in subtle, yet profoundly important, manners."To determine the relationship between sulfates and ozone loss, the authors used a combination of measurements and computer simulations. They then estimated future ozone loss by looking at two geoengineering schemes--one that would use volcanic-sized sulfates and a second that would use much smaller injections.The study found that injections of small particles, over the next 20 years, could reduce the ozone layer by 100 to 230 Dobson Units. This would represent a significant loss of ozone because the average thickness of the ozone layer in the Northern Hemisphere is 300 to 450 Dobson Units. (A Dobson Unit is equivalent to the number of ozone molecules that would create a layer 0.01 millimeters thick under conditions at Earth's surface).With large particles, the Arctic loss would range from 70 to 150 Dobson Units. In each case, the larger figure is correlated with colder winters.The ozone loss would drop in the later part of the century to about 60 to 150 Dobson Units, depending on the size of the sulfates and the severity of winters.In the Antarctic, most of the ozone is already depleted and the sulfate injections would not significantly reduce the thickness of the ozone layer. Instead, they would significantly delay the recovery of the ozone hole.The authors caution that the actual impacts on ozone could be somewhat different than estimated if atmospheric changes led to unusually warm or cold polar winters. They also warn that a geoengineering project could lead to even more severe ozone loss if a major volcanic eruption took place at the same time."Clearly much more research needs to be conducted to determine the full implications of geoengineering before we may seriously consider the injection of sulfate aerosols into the stratosphere," says co-author Rolf Moeller of the Joelich Research Center in Germany.The University Corporation for Atmospheric Research manages the National Center for Atmospheric Research under primary sponsorship by the National Science Foundation (NSF). Opinions, findings, conclusions, or recommendations expressed in this document are those of the author(s) and do not necessarily reflect the views of the National Science Foundation, NASA, or other funding agencies.Journal reference: Simone Tilmes, Rolf Moeller, and Ross Salawitch. The sensitivity of polar ozone depletion to proposed geo-engineering schemes. Science Express, April 24, 2008The study was funded by the National Science Foundation, which is NCAR's principal sponsor, as well as by NASA and European funding agencies.

Ozone Holes

April 24, 2008

https://www.sciencedaily.com/releases/2008/04/080424113454.htm

Ozone Hole Recovery May Reshape Southern Hemisphere Climate Change And Amplify Antarctic Warming

A full recovery of the stratospheric ozone hole could modify climate change in the Southern Hemisphere and even amplify Antarctic warming, according to scientists from the University of Colorado at Boulder, the National Oceanic and Atmospheric Administration and NASA.

While Earth's average surface temperatures have been increasing, the interior of Antarctica has exhibited a unique cooling trend during the austral summer and fall caused by ozone depletion, said Judith Perlwitz of the Cooperative Institute for Research in Environmental Sciences, a joint institute of CU-Boulder and NOAA. "If the successful control of ozone-depleting substances allows for a full recovery of the ozone hole over Antarctica, we may finally see the interior of Antarctica begin to warm with the rest of the world," Perlwitz said.Perlwitz is lead author of a new study on the subject to be published April 26 in Geophysical Research Letters. Co-authors include Steven Pawson and Eric Nielson of NASA's Goddard Space Flight Center in Greenbelt, Md., and Ryan Fogt and William Neff of NOAA's Earth System Research Laboratory in Boulder. The study was supported by NASA's Modeling and Analysis Program.The authors used a NASA supercomputer model that included interactions between the climate and stratospheric ozone chemistry to examine how changes in the ozone hole influence climate and weather near Earth's surface, said Perlwitz.The study authors calculated that when stratospheric ozone levels return to near pre-1969 levels by the end of the 21st century, large-scale atmospheric circulation patterns now shielding the Antarctic interior from warmer air masses to the north will begin to break down during the austral summer. The circulation patterns are collectively known as a positive phase of the Southern Annular Mode, or SAM.The scientists found that as ozone levels recover, the lower stratosphere over the polar region will absorb more harmful ultraviolet radiation from the sun. This could cause air temperatures roughly 6 to 12 miles above Earth's surface to rise by as much as 16 degrees Fahrenheit, reducing the strong north-south temperature gradient that currently favors the positive phase of SAM, said the research team.The supercomputer modeling effort also indicated that ozone hole recovery would weaken the intense westerly winds that currently whip around Antarctica and block air masses from crossing into the continent's interior. As a result, Antarctica would no longer be isolated from the warming patterns affecting the rest of the world.NASA's Pawson said ozone recovery over Antarctica would essentially reverse summertime climate and atmospheric circulation changes that have been caused by the presence of the ozone hole. "It appears that ozone-induced climate change occurred quickly, over 20 to 30 years, in response to the rapid onset of the ozone hole," he said. "These seasonal changes will decay more slowly than they built up, since it takes longer to cleanse the stratosphere of ozone-depleting gases than it took for them to build up."The seasonal shift in large-scale circulation patterns could have repercussions for Australia and South America as well. Other studies have shown that the positive phase of SAM is associated with cooler temperatures over much of Australia and increased rainfall over Australia's southeast coastline.During late spring and early summer, the positive phase of SAM also is associated with drier conditions in South America's productive agricultural areas like Argentina, Brazil, Uruguay and Paraguay, said Perlwitz. If ozone recovery induces a shift away from a positive SAM, Australia could experience warmer and drier conditions while South America could get wetter, she said.But just how influential a full stratospheric ozone recovery will be on Southern Hemisphere climate largely depends on the future rate of greenhouse gas emissions, according to the GRL authors. Projected increases in human-emitted greenhouse gases like carbon dioxide will be the main driver for strengthening the positive phase of SAM."In running our model simulations, we assumed that greenhouse gases like carbon dioxide would double over the next 40 years and then slowly level off," said Perlwitz. "If human activities cause more rapid increases in greenhouse gases, or if we continue to produce these gases for a longer period of time, then the positive SAM may dominate year-round and dwarf any climatic effects caused by ozone recovery."NASA's High-End Computing Program provided the Columbia supercomputer resources at the NASA Ames Research Center in Moffett Field, Calif.

Ozone Holes

April 23, 2008

https://www.sciencedaily.com/releases/2008/04/080422135728.htm

Link Between Ozone Air Pollution And Premature Death Confirmed

Short-term exposure to current levels of ozone in many areas is likely to contribute to premature deaths, says a new National Research Council report, which adds that the evidence is strong enough that the U.S. Environmental Protection Agency should include ozone-related mortality in health-benefit analyses related to future ozone standards.  The committee that wrote the report was not asked to consider how evidence has been used by EPA to set ozone standards, including the new public health standard set by the agency in March. 

Ozone, a key component of smog, can cause respiratory problems and other health effects.  In addition, evidence of a relationship between short-term -- less than 24 hours -- exposure to ozone and mortality has been mounting, but interpretations of the evidence have differed, prompting EPA to request the Research Council report.  In particular, the agency asked the committee to analyze the ozone-mortality link and assess methods for assigning a monetary value to lives saved for the health-benefits assessments. Based on a review of recent research, the committee found that deaths related to ozone exposure are more likely among individuals with pre-existing diseases and other factors that could increase their susceptibility.  However, premature deaths are not limited to people who are already within a few days of dying. In addition, the committee examined research based on large population groups to find how changes in ozone air concentration could affect mortality, specifically to determine the existence of a threshold -- a concentration of ozone below which exposure poses no risk of death.  The committee concluded that if a threshold exists, it is probably at a concentration below the current public health standard.  As people have individual susceptibilities to ozone exposure, not everyone may experience an altered risk of death if ozone air concentration also changes.  Further research should explore how personal thresholds may vary and the extent to which they depend on a person's frailty, the committee said.The research on short-term exposure does not account for all ozone-related mortality, and the estimated risk of death may be greater than if based solely on these studies, the committee noted.  To better understand all the possible connections between ozone and mortality, future research should address whether exposure for more than 24 hours and long-term exposure -- weeks to years -- are associated with mortality, including how ozone exposure could impact life expectancy.  For example, deaths related to short-term exposure may not occur until several days afterward or may be associated with multiple short-term exposures.Additionally, EPA should monitor ozone during the winter months when it is low and in communities with warmer and cooler winters to better understand seasonal and regional differences in risk.  More research could also look at how other pollutants, such as airborne particulate matter, may affect ozone and mortality risk.EPA, like other federal agencies, is required to carry out a cost-benefit analysis on mitigation actions that cost more than $100 million per year.  EPA recently used the results of population studies to estimate the number of premature deaths that would be avoided by expected ozone reductions for different policy choices, and then assigned a monetary value to the avoided deaths by using the value of a statistical life (VSL). The VSL is derived from studies of adults who indicate the "price" that they would be willing to pay -- i.e. what benefits or conveniences someone would be willing to forgo -- to change their risk of death in a given period by a small amount.  The monetary value of the improved health outcome is based on the value the group places on receiving the health benefit; it is not the value selected by policymakers or experts.EPA applies the VSL to all lives saved regardless of the age or health status.  For instance, a person who is 80 years old in poor health is estimated to have the same VSL as a healthy 2-year-old.  To determine if an approach that accounts for differences in remaining life expectancy could be supported scientifically, EPA asked the committee to examine the value of extending life.  For example, EPA could calculate VSL to estimate the value of remaining life, so a 2-year-old would have a higher VSL than an 80-year-old.  It is plausible that people with shorter remaining life expectancy would be willing to devote fewer resources to reducing their risk of premature death than those with longer remaining life expectancy.  In contrast, if the condition causing the shortened life expectancy could be improved and an acceptable quality of life can be preserved or restored, people may put a high value on extending life, even if they have other health impairments or are quite elderly.The committee concluded that EPA should not adjust the VSL because current evidence is not sufficient to determine how the value might change according to differences in remaining life expectancy and health status.  However, the committee did not reject the idea that such adjustments may be appropriate in the future.  To move toward determining a value of remaining life, alternative approaches should be explored in sensitivity analyses, and further research should be conducted to answer the questions raised about the validity of EPA's current approach.  The study was sponsored by the U.S. Environmental Protection Agency.  The National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council make up the National Academies.  They are private, nonprofit institutions that provide science, technology, and health policy advice under a congressional charter.  The Research Council is the principal operating agency of the National Academy of Sciences and the National Academy of Engineering.  

Ozone Holes

April 18, 2008

https://www.sciencedaily.com/releases/2008/04/080414103617.htm

Seven Months On A Drifting Ice Floe

For the first time, a German has taken part in a Russian drift expedition and has explored the atmosphere above the central Arctic during the polar night. Jürgen Graeser, a member of the Potsdam Research Unit of the Alfred-Wegener-Institute for Polar and Marine Research in the Helmholtz Association, has just returned home to Germany. As a member of the Russian expedition NP 35 (35. North Pole Drift Expedition), which consisted of 21 persons, he has spent seven months on a drifting ice floe in the Arctic.

The 49-year-old scientific technician has gained observational data from a region, which is normally inaccessible during the Arctic winter and therefore widely unexplored. Ascends with a tethered balloon up to an altitude of 400 metres as well as balloon borne sensor ascends up to an altitude of 30 kilometres provided data which will contribute to ameliorate existing climate models for the Arctic.In spite of its importance for the global climate system, the Arctic is still a blank on the data map. Up to now, continuous measuring in the atmosphere above the Arctic Ocean is missing. „We are not able to develop any reliable climate scenarios without disposing of data series with high temporal and local resolutions about the Arctic winter. The data which Jürgen Graeser has obtained in the course of the NP 35 expedition are unique, and they are apt to considerably diminish the still existing uncertainties in our climate models“ said Prof. Dr. Klaus Dethloff, project leader at the Alfred Wegener Institute for Polar and Marine Research.Since 1937/38, the Russian Institute for Arctic and Antarctic Research (AARI) has already operated 34 Russian North Pole drift stations. In the course of the International Polar Year 2007/2008, for the first time a foreigner was allowed to take part in a drift expedition (NP 35). Due to their close co-operation with the AARI, the scientists of the Potsdam Research Unit of the Alfred Wegener Institute now could realize a project to research the polar atmosphere in the hardly accessible region of the Arctic Ocean.From September 2007 to April 2008, the scientific technician Jürgen Graeser from the Potsdam Research Unit was a member of the NP 35 team. For seven months, the 49-year-old has lived and worked together with twenty Russian colleagues on an ice flow the size of three times five kilometres. While Graeser concentrated on measuring the Arctic atmosphere, the Russian scientists performed investigations of the ocean top layer, the characteristics of the sea ice, the snow coverage and the energy balance above the ice surface. Moreover, they recorded atmospherical data concerning temperature, moisture, wind and air pressure by means of earth stations as well as with ascends of radio sensors. In the course of the winter the ice floe drifted 850 kilometres in northwestern direction over the Arctic Ocean.In April Jürgen Graser was picked up from the ice floe by Polar 5, the research aircraft of the Alfred-Wegener-Institute. A specialised pilot, Brian Burchartz from Enterprise Airlines Oshawa, Canada, accomplished the difficult landing and take-off operation on the ice. “I experienced my stay on the ice floe as an incredible enrichment, under personal as well as professional aspects,” Jürgen Graeser said. The Russian colleagues will continue their measurements until the planned evacuation of the station in September 2008.During the drift Jürgen Graeser has explored the atmosphere above the Arctic Ocean. In order to measure the meteorological structure of the Arctic boundary layer and its temporal changes, he regularly sent out a tethered balloon filled with helium. The six sensors fixed on the tether registered data for temperature, air pressure, moisture and wind and sent them to Greaser’s computer. The exchange processes of heat, impulses and moisture between the earth surface and the atmosphere, which are important for the climate, take place in the layer between the ground and an altitude of about 400 metres.For the first time now the local and temporal structure of ground-level temperature inversions was measured during the complete polar night. To evaluate and interpret the data, the scientists in Potsdam performed simulations with a regional climate model of the Arctic. Preliminary comparisons of temperature profiles measured on the ice floe with those from the regional climate model underline the importance of the measurements performed by Jürgen Graeser. Considerable deviations are shown between the observed data and model data in the region between the ground and an altitude of about 400 metres. Subsequent research activities in Potsdam focus on the connection of the Arctic boundary layer with the development and the tracks of low-pressure areas.Vertical high-resolution ozone data from the central Arctic are rare. To close this data gap, Jürgen Graeser regularly launched a research balloon equipped with a radiosonde and an ozone sensor. These balloons carry the sensors up to an altitude of about 30 kilometres. In the past winter, the region of the ozone layer in an altitude of about 20 kilometres was exceptionally cold, thus continuing the trend to colder conditions in this altitude that was observed in the past. The cold conditions have fostered considerable destruction of the Arctic ozone layer in the past winter. The unique measurements of NP 35 will significantly contribute to determine precisely how much of the ozone destruction is caused by human activities.„The high amount of work caused by the extensive measuring program let the time on the ice flow go by extremely fast“, Jürgen Graeser said on his return. Daily life was structured by the measurements on the one hand and by the meals with the colleagues on the other. A cook was responsible for the meals of the whole team, but each overwinterer helped him with the kitchen work for one day every three weeks. This kitchen service coincided with the station service controlling the condition of the ice floe and the presence of polar bears near the station. These tasks turned out to be very important, for in the course of the winter the ice floe produced crevices several times, but those crevices closed again. Moreover, frequent visits of polar bears regularly caused for alarm among the participants. Jürgen Graeser had the possibility to communicate with the Potsdam colleagues via satellite telephone and to relay the actual measuring data promptly.The long-term aim is to significantly reduce the great imprecision of present climate models in polar regions. To create models, mathematical descriptions for physical processes taking place under natural conditions are used. These so-called „parameterizations“ are based on measured data, and only an excellent data base can enable them to produce realistic climate simulations. In November 2008, the scientists taking part in the NP-35 project will discuss the results of their expedition in the course of an international workshop in Potsdam. Altogether, the NP-35 project is one more significant milestone for the Potsdam atmospheric researchers. The results deliver an important base for the international focal projects CliC (Climate and Cryosphere) and SPARC (Stratospheric Processes and their Role in Climate Change) by the World Climate Research Programme (WCRP, wcrp.wmo.int/).

Ozone Holes

April 14, 2008

https://www.sciencedaily.com/releases/2008/04/080408163231.htm

Sea Salt Worsens Coastal Air Pollution

Air pollution in the world's busiest ports and shipping regions may be markedly worse than previously suspected, according to a new study showing that industrial and shipping pollution is exacerbated when it combines with sunshine and salty sea air.

In a paper published in the journal Nature Geoscience, a team of researchers that included University of Calgary chemistry professor Hans Osthoff report that the disturbing phenomenon substantially raises the levels of ground-level ozone and other pollutants in coastal areas."We found unexpectedly high levels of certain air pollutants where pollution from cities and ships meets salt in the ocean air along the southeast coast of the United States," said Osthoff, who joined the U of C's Department of Chemistry last August. "It only makes sense that this is a problem everywhere industrial pollution meets the ocean, as is the case in many of the largest cities around the world. It also changes our view of the chemical transformations that occur in ship engine exhaust plumes, and tells us that emissions from marine vessels may be polluting the globe to a greater extent than currently estimated."Dr. Osthoff was part of a National Oceanic and Atmospheric Administration (NOAA) team that spent six weeks monitoring air quality in busy shipping areas off the southeastern coast of the United States between Charleston, South Carolina and Houston, Texas, in the summer of 2006. The researchers found unexpectedly high levels of nitryl chloride (ClNO2), a chemical long suspected to be involved in ground-level ozone production along the coast.They then determined that the compound is efficiently produced at night by the reaction of the nitrogen oxide N2O5 in polluted air with chloride from sea salt. With the help of sunlight, the chemical then splits into radicals that accelerate production of ozone and, potentially, fine particulate matter, which are the main components of air pollution. Their findings also show that up to 30 per cent of the ground-level ozone present in seaside cities such as Houston may be the result of pollution mixing with salt from ocean mist.Dr. Osthoff intends to continue to work on halogen compounds at the University of Calgary."The Texas study covered only a very limited geographic area. We would like to find out to what extent this chemistry affects air quality in other regions, for example, the the Greater Vancouver area, or the Arctic," he said. "Our study indicates that halide salts such as chloride or bromide, which have been thought of as being relatively inert, may be playing a much greater role overall in the lower atmosphere."The paper "High levels of nitryl chloride in the polluted subtropical marine boundary layer" is available in the April 6, 2008 advance online edition of the journal Nature Geoscience. The print version is scheduled to appear on May 1st, 2008.

Ozone Holes

April 8, 2008

https://www.sciencedaily.com/releases/2008/04/080407172710.htm

Regional Nuclear Conflict Would Create Near-global Ozone Hole, Says Study

A limited nuclear weapons exchange between Pakistan and India using their current arsenals could create a near-global ozone hole, triggering human health problems and wreaking environmental havoc for at least a decade, according to a study led by the University of Colorado at Boulder.

The computer-modeling study showed a nuclear war between the two countries involving 50 Hiroshima-sized nuclear devices on each side would cause massive urban fires and loft as much as 5 million metric tons of soot about 50 miles into the stratosphere, said CU-Boulder Research Associate Michael Mills, chief study author. The soot would absorb enough solar radiation to heat surrounding gases, setting in motion a series of chemical reactions that would break down the stratospheric ozone layer protecting Earth from harmful ultraviolet radiation, said Mills."We would see a dramatic drop in ozone levels that would persist for many years," said Mills of CU-Boulder's Laboratory for Atmospheric and Space Physics. "At mid- latitudes the ozone decrease would be up to 40 percent, which could have huge effects on human health and on terrestrial, aquatic and marine ecosystems."A paper on the subject, titled "Massive Global Ozone Loss Predicted Following A Regional Nuclear Conflict," appeared the week of April 7 in the Proceedings of the National Academy of Sciences. Co-authors on the study include CU-Boulder Professor Brian Toon, UCLA Professor Richard Turco and National Center for Atmospheric Research scientists Douglas Kinnison and Rolando Garcia.According to the computer simulations, fires ignited in large cities by nuclear explosions would send several million metric tons of soot into the upper stratosphere, which would be heated by massive smoke injections. Higher temperatures would accelerate catalytic reaction cycles in the stratosphere, particularly reactions of nitrogen oxide gases known collectively as NOx that destroy ozone, Mills said.In addition to ozone losses of 25 percent to 40 percent at mid-latitudes, the models show a 50 percent to 70 percent ozone loss at northern high latitudes, said Mills. "The models show this magnitude of ozone loss would persist for five years, and we would see substantial losses continuing for at least another five years," he said.The ozone losses predicted in the study are much larger than losses estimated in previous "nuclear winter" and "ultraviolet spring" scenario calculations following nuclear conflicts, said Toon, chair of CU-Boulder's oceanic and atmospheric sciences department. A 1985 National Research Council Report predicted a global nuclear exchange involving thousands of megatons of explosions, rather than the 1.5 megatons assumed in the PNAS study, would deplete only 17 percent of the Northern Hemisphere's stratospheric ozone, which would recover by half in three years."The missing piece back then was that the models at the time could not account for the rise of the smoke plume and consequent heating of the stratosphere," said Toon. "The big surprise is that this study demonstrates that a small-scale, regional nuclear conflict is capable of triggering ozone losses even larger than losses that were predicted following a full-scale nuclear war."Human health ailments like cataracts and skin cancer, as well as damage to plants, animals and ecosystems at mid-latitudes would likely rise sharply as ozone levels decreased and allowed more harmful UV light to reach Earth, according to the PNAS study. "By adopting the Montreal Protocol in 1987, society demonstrated it was unwilling to tolerate a small percentage of ozone loss because of serious health risks," said Toon. "But ozone loss from a limited nuclear exchange would be more than an order of magnitude larger than ozone loss from the release of gases like CFCs."UV radiation has been shown to be particularly damaging to inhabitants of aquatic ecosystems, including amphibians, shrimp, fish and phytoplankton, said Mills. "Most organisms can do little to avoid UV exposure, so one of the big unanswered questions is how the biota would respond to these big UV increases triggered by a nuclear exchange."The team used a cluster of computer processors at LASP to run three separate 10-year simulations -- each more than 300 hours long -- linking the urban fire nuclear scenario to climate and atmospheric chemistry processes. The team coupled NCAR's Whole Atmosphere Community Climate Model 3 with the Community Aerosol and Radiation Model for Atmospheres developed by CU-Boulder and NASA Ames.Two 2006 studies led by Toon and involving UCLA and Rutgers University showed that such a small-scale regional nuclear war could produce as many fatalities as all of World War II and disrupt global climate for a decade or more. Of the eight nations known to possess nuclear weapons, even those with the smallest nuclear arsenals, like Pakistan and India, are believed to have 50 or more Hiroshima-sized weapons.In addition, about 40 countries possess enough plutonium, uranium or a combination of both to construct substantial nuclear arsenals, said Toon. A nuclear exchange involving 100 15-kiloton, Hiroshima-type weapons is only 0.03 percent of the total explosive power of the world's nuclear arsenal, he said."We hope other research groups repeat our calculations and undertake their own scientific studies on this issue," said Toon. "The world has become a far more dangerous place when the actions of two countries on the other side of the world could have such a drastic impact on the planet." The study was funded by CU-Boulder.

Ozone Holes

March 25, 2008

https://www.sciencedaily.com/releases/2008/03/080320150032.htm

Chemists Find New Important Contributor To Urban Smog

Chemists at the University of California, San Diego have discovered that a chemical reaction in the atmosphere above major cities long assumed to be unimportant in urban air pollution is in fact a significant contributor to urban ozone -- the main component of smog.

Their finding, detailed in the March 21 issue of the journal Science, should help air quality experts devise better strategies to reduce ozone for the more than 300 counties across the United States with ozone levels that exceed new standards announced recently by the Environmental Protection Agency.It should also benefit cities in the rest of the world such as Mexico City and Beijing that are now grappling with major air quality and urban smog problems. More than 100 million people worldwide currently live in cities that fail to meet international standards for air quality."This study provides us with additional insight into the chemistry of urban ozone production," said Amitabha Sinha, a professor of chemistry and biochemistry at UC San Diego who headed the research team. "It shows us that the chemistry of urban ozone is even more complicated than we initially assumed. With improved knowledge of how ozone is produced, we should be in a better position to control the air quality of large urban areas across the United States as well as around the world."Urban ozone levels peak in the afternoon hours of large cities after being generated through a complex series of chemical reactions involving the interaction of sunlight with hydrocarbons and nitrogen oxides from automobile exhaust. Ozone production is initiated when hydroxyl radicals, OH, are produced from water vapor. Atmospheric chemists had long assumed that the lion's share of the OH involved in urban ozone production is generated when ultraviolet radiation with wavelengths less than 320 nanometers dissociates ambient ozone to form excited oxygen atoms, which, in turn, react with water vapor to produce hydroxyl radicals. These OH radicals subsequently attack hydrocarbons and the resulting products combine through a series of chemical reactions with nitric oxide, NO, to produce nitrogen dioxide, NOSinha's team found in laboratory experiments that another chemical reaction also plays a significant role in urban OH radical production--perhaps comparable to that from the reaction of excited oxygen atoms with water vapor under certain conditions. This new mechanism involves reactions between water vapor and NOGerman scientists first proposed this method of producing OH radicals in 1997. Their measurements, however, did not detect any OH radicals being formed and, as a result, they suggested that the reaction would play a fairly insignificant role in the atmosphere.The more recent measurements by the UC San Diego team suggest that this method of OH radical production occurs at a rate that is ten times faster than previously estimated. And because radiation in the 450 to 650 nanometers wavelength range is not filtered out as effectively in the lowest portion of the atmosphere as the ultraviolet radiation in the vicinity of 320 nanometers that generate OH radicals from water vapor and ozone, Sinha and other atmospheric scientists believe it's likely to have a major role in the formation of smog."Identifying the sources of atmospheric OH radical production is important to understanding how to control the ozone problem, since it is the reaction of OH radicals with hydrocarbons that ultimately leads to urban ozone," Sinha said. "The chemistry of urban ozone production is complicated and it just got bit more complicated with the addition of this new source of OH radicals."Sinha's team--which included postdoctoral fellow Shuping Li and graduate student Jamie Matthews--was able to make the most precise measurement to date of the rate of this reaction with an innovative laser technique that allowed the team to directly monitor the OH radicals with significantly higher sensitivity then previously used to study this reaction."It's a relatively slow reaction with a rate that is at least a thousand times slower than that for producing OH from the reaction of excited oxygen atoms with water molecules," said Sinha. "However, there is a lot of solar radiation coming down over the visible wavelength region, so even a slow reaction can become important. The upshot is that atmospheric models have ignored this reaction altogether, assuming that because nothing can be seen using conventional techniques, nothing must be happening."The research was supported in part by the Petroleum Research Fund of the American Chemical Society and the National Science Foundation.

Ozone Holes

March 11, 2008

https://www.sciencedaily.com/releases/2008/03/080307224040.htm

Stratospheric Ozone Chemistry Plays An Important Role For Atmospheric Airflow Patterns

Interactions between the stratospheric ozone chemistry and atmospheric air flow lead to significant changes of airflow patterns from the ground up to the stratosphere. Scientists at the Research Unit Potsdam of the Alfred Wegener Institute for Polar and Marine Research have investigated this fundamental process for climate interactions in the Arctic, and for the first time, incorporated it into climate models. Until now, it was not known what caused the natural variations of atmospheric air flow patterns which have played  an important role for climate changes in the last decades.

Atmospheric airflows follow certain preferred patterns. The most important pattern for the northern hemisphere is the Arctic Oscillation. It's a spacious oscillation of the atmosphere that is characterized by opposing anomalies in air pressure in the central Arctic region and in parts of the mid- and subtropical latitudes. This oscillation of the atmosphere lasts for decades although it can be more or less pronounced.In the positive phase of the Arctic Oscillation, which has been predominant since 1970, the polar vortex during the winter is stable and the exchange of air masses between the mid- and higher latitudes is limited. In mid-latitudes strong westerly winds bring warm air from the Atlantic Ocean to North and Central Europe and Siberia during the winter. In the negative phase of the Arctic Oscillation cold polar air can penetrate further south which leads to harsh winters in Europe.So far feedback between the chemical processes in the stratosphere and the circulation in the troposphere and stratosphere (height between 0 and 10 kilometers or 10 and about 50 kilometers) have not been included in complex global climate models linking atmosphere and ocean. For the first time, scientists from the Alfred Wegener Institute have included a module of stratospheric ozone chemistry into a coupled global climate model. The scientists show that ozone chemistry significantly influences the Arctic Oscillation by comparing simulations of the standard model with results from the model extended by the new ozone chemistry module. Changes of atmospheric air flows and temperature distribution lead to an increase of the negative phase of the Arctic Oscillation during the winter seasons."Our research is an important contribution to reduce the uncertainty in the simulation of today's climate. Today's climate models carry, contrary to many claims, still a high level of uncertainty. Only by understanding the basic processes in the Arctic, can we quantify these deviations and eliminate them," said Sascha Brand of the Alfred Wegener Institute, main author of the published study. The results indicate that if interactions between atmospheric air flow and stratospheric ozone chemistry are being taken into account, they will also have an influence on the stability of the polar vortex in the simulation of future climate developments and should therefore be included in climate models. In a follow-up project, the new model will be used for the calculation of future climate developments.This research has just been published in the journal Geophysical Research Letters (Brand et al, Geophys. Res. Lett.).

Ozone Holes

March 4, 2008

https://www.sciencedaily.com/releases/2008/02/080226135421.htm

Carbon Dioxide Tied To Air Pollution Mortality

Rising carbon dioxide (CO

Yet because it does not affect respiration directly, COThis can harm lung function and irritate the respiratory system. Using a high-resolution model that correlates pollution levels to human health, the author finds that each one degree Celsius rise in temperature may increase U.S. annual air pollution deaths by about 1000.About 40 percent of these deaths may result from elevated ground-level ozone concentrations. The rest are likely from particles, which would increase due to COThe author notes that many of these deaths would occur in urban populations subject to smog, as are residents of some areas of California. Extrapolating U.S. deaths to global population yields about 22,000 excess deaths expected worldwide each year.Journal reference: Mark Z. Jacobson (Stanford University). On the causal link between carbon dioxide and air pollution mortality. Geophysical Research Letters (GRL) paper doi. 10.1029/2007GL031101, 2008 

Ozone Holes

February 29, 2008

https://www.sciencedaily.com/releases/2008/02/080227102848.htm

Gene That Controls Ozone Resistance Of Plants Could Lead To Drought-resistant Crops

Biologists at the University of California, San Diego, working with collaborators at the University of Helsinki in Finland and two other European institutions, have elucidated the mechanism of a plant gene that controls the amount of atmospheric ozone entering a plant’s leaves.

Their finding helps explain why rising concentrations of carbon dioxide in the atmosphere may not necessarily lead to greater photosynthetic activity and carbon sequestration by plants as atmospheric ozone pollutants increase. And it provides a new tool for geneticists to design plants with an ability to resist droughts by regulating the opening and closing of their stomata—the tiny breathing pores in leaves through which gases and water vapor flow during photosynthesis and respiration.“Droughts, elevated ozone levels and other environmental stresses can impact crop yields,” said Jean Chin, who oversees membrane protein grants at the National Institute of General Medical Sciences, which partially funded the research. “This work gives us a clearer picture of how plants respond to these kinds of stresses and could lead to new ways to increase their resistance.”The discovery is detailed in the advance online publication of the journal Nature by biologists at UCSD, University of Helsinki in Finland, University of Tartu in Estonia and the University of the West of England. Last year, the journal published another study by British researchers that found that ozone generated from the nitrogen oxides of vehicle emissions would significantly reduce the ability of plants to increase photosynthesis and store the excess carbon in the atmosphere projected from rising levels of carbon dioxide.“When ozone enters the leaf through the stomatal pores, it damages the plants photosynthetic machinery and basically causes green leaves to lose their color, a process called chlorosis,” said Julian Schroeder, a professor of biological sciences at UC San Diego and one of the principal authors of the recent study. “Plants have a way to protect themselves and they do that by closing the stomatal pores when concentrations of ozone increase.”While this protective mechanism minimizes the damage to plants, he adds, it also minimizes their ability to photosynthesize when ozone levels are high, because the stomatal pores are also the breathing holes in leaves through which carbon dioxide enters leaves. The result is diminished plant growth or at least less than one might expect given the rising levels of carbon dioxide.Some scientists assessing the impacts of rising greenhouse gases had initially estimated that increased plant growth generated from extra carbon dioxide in the atmosphere could sequester much of the excess atmospheric carbon in plant material. But in a paper published last July in Nature, researchers from Britain’s Hadley Centre for Climate Prediction and Research concluded that the damage done to plants by increasing ozone pollution would actually reduce the ability of plants to soak up carbon from the atmosphere by 15 percent which corresponds to about 30 billion tons of carbon per year on a global scale---a dire prediction given that humans are already putting more carbon into the atmosphere than plants can soak up.The discovery of the ozone-responsive plant gene was made when Jaakko Kangasjarvi and his collaborators at the University of Helsinki in Finland found a mutant form of the common mustard plant, Arabidopsis, that was extremely sensitive to ozone. They next found that this mutant does not close its stomatal pores in response to ozone stress.“When the mutant plant is exposed to ozone, the leaves lose their dark green color and eventually become white,” said Kangasjarvi, who is also one of the principal authors of the study. “This is because the stomatal pores in the leaves stay open even in the presence of high ozone and are unable to protect the plant.”The scientists found that the gene responsible for the mutation is essential for the function of what they called a “slow or S-type anion channel.” Anions are negatively charged ions and these particular anion channels are located within specialized cells called guard cells that surround the stomatal pores. The gene was therefore named SLAC1 for “slow anion channel 1.”Guard cells close stomatal pores in the event of excess ozone or drought. When this gene is absent or defective, the mutant plant fails to close its stomatal pores.In 1989, Schroeder discovered these slow anion channels in guard cells by electrical recordings from guard cells using tiny micro-electrodes. He predicted that these anion channels would be important for closing the stomatal breathing pores in leaves under drought stress.“The model we proposed back then was that the anion channels are a kind of electrical tire valve in guard cells, because our studies suggested that closing stomatal pores requires a type of electrically controlled deflation of the guard cells,” he said. “But finding the gene responsible for the anion channels has eluded many researchers since then.”The latest study shows that the SLAC1 gene encodes a membrane protein that is essential for the function of these anion channels.  “We analyzed a lot of mechanisms in the guard cells and, in the end, the slow anion channels were what was missing in the mutant,” said Yongfei Wang, a post doctoral associate in Schroeder’s lab and co-first author of the paper.The scientists showed that the SLAC1 gene is required for stomatal closing to various stresses, including ozone and the plant hormone abscisic acid, which controls stomatal closing in response to drought stress. Elevated carbon dioxide in the atmosphere also causes a partial closing of stomatal pores in leaves. By contrast, the scientists found, the mutant gene does not close the plants’ stomatal pores when carbon dioxide levels are elevated.“We now finally have genetic evidence for the electric tire valve model and the gene to work with,” said Schroeder.Because the opening and closing of stomatal pores also regulates water loss from plants, Schroeder said, understanding the genetic and biochemical mechanisms that control the guard cells during closing of the stomatal pores in response to stress can have important applications for agricultural scientists seeking to genetically engineer crops and other plants capable of withstanding severe droughts.“Plants under drought stress will lose 95 percent of their water through evaporation through stomatal pores, and the anion channel is a central control mechanism that mediates stomatal closing, which reduces plant water loss,” he said.The study was financed by grants from the National Science Foundation and the National Institute of General Medical Sciences.

Ozone Holes

January 28, 2008

https://www.sciencedaily.com/releases/2008/01/080125154628.htm

American Geophysical Union Revises Position On Climate Change

A statement released on January 24 by the world's largest scientific society of Earth and space scientists--the American Geophysical Union, or AGU--updates the organization's position on climate change: the evidence for it, potential consequences from it, and how to respond to it.

The statement, Human Impacts on Climate, presented below, is the first revision since 2003 of the climate-change position of the AGU, which has a membership of 50,000 researchers, teachers, and students in 137 countries. The society adopted the statement at a meeting of AGU's leadership body, the AGU Council, in San Francisco, California, on 14 December 2007.The Earth's climate is now clearly out of balance and is warming. Many components of the climate system--including the temperatures of the atmosphere, land and ocean, the extent of sea ice and mountain glaciers, the sea level, the distribution of precipitation, and the length of seasons--are now changing at rates and in patterns that are not natural and are best explained by the increased atmospheric abundances of greenhouse gases and aerosols generated by human activity during the 20th century. Global average surface temperatures increased on average by about 0.6°C over the period 1956--2006.As of 2006, eleven of the previous twelve years were warmer than any others since 1850. The observed rapid retreat of Arctic sea ice is expected to continue and lead to the disappearance of summertime ice within this century. Evidence from most oceans and all continents except Antarctica shows warming attributable to human activities. Recent changes in many physical and biological systems are linked with this regional climate change. A sustained research effort, involving many AGU members and summarized in the 2007 assessments of the Intergovernmental Panel on Climate Change, continues to improve our scientific understanding of the climate.During recent millennia of relatively stable climate, civilization became established and populations have grown rapidly. In the next 50 years, even the lower limit of impending climate change--an additional global mean warming of 1°C above the last decade--is far beyond the range of climate variability experienced during the past thousand years and poses global problems in planning for and adapting to it. Warming greater than 2°C above 19th century levels is projected to be disruptive, reducing global agricultural productivity, causing widespread loss of biodiversity, and--if sustained over centuries--melting much of the Greenland ice sheet with ensuing rise in sea level of several meters. If this 2°C warming is to be avoided, then our net annual emissions of COWith climate change, as with ozone depletion, the human footprint on Earth is apparent. The cause of disruptive climate change, unlike ozone depletion, is tied to energy use and runs through modern society. Solutions will necessarily involve all aspects of society. Mitigation strategies and adaptation responses will call for collaborations across science, technology, industry, and government. Members of the AGU, as part of the scientific community, collectively have special responsibilities: to pursue research needed to understand it; to educate the public on the causes, risks, and hazards; and to communicate clearly and objectively with those who can implement policies to shape future climate.Adopted by AGU Council, December, 2003Revised and Reaffirmed, December, 2007

Ozone Holes

January 23, 2008

https://www.sciencedaily.com/releases/2008/01/080121181408.htm

Rich Nations' Environmental Footprints Tread Heavily On Poor Countries

The environmental damage caused by rich nations disproportionately impacts poor nations and costs them more than their combined foreign debt, according to a first-ever global accounting of the dollar costs of countries' ecological footprints.

The study, led by former University of California, Berkeley, research fellow Thara Srinivasan, assessed the impacts of agricultural intensification and expansion, deforestation, overfishing, loss of mangrove swamps and forests, ozone depletion and climate change during a 40-year period, from 1961 to 2000. In the case of climate change and ozone depletion, the researchers also estimated the impacts that may be felt through the end of this century."At least to some extent, the rich nations have developed at the expense of the poor and, in effect, there is a debt to the poor," said coauthor Richard B. Norgaard, an ecological economist and UC Berkeley professor of energy and resources. "That, perhaps, is one reason that they are poor. You don't see it until you do the kind of accounting that we do here."The calculation of the ecological footprints of the world's low-, middle- and high-income nations drew upon more than a decade of assessments by environmental economists who have tried to attach monetary figures to environmental damage, plus data from the recent United Nations Millennium Ecosystem Assessment and World Bank reports.Because of the monumental nature of such an accounting, the UC Berkeley researchers limited their study to six areas of human activity. Impacts of activities that are difficult to assess, such as loss of habitat and biodiversity and the effects of industrial pollution, were ignored. Because of this, the researchers said that the estimated financial costs in the report are a minimum."We think the measured impact is conservative. And given that it's conservative, the numbers are very striking," said Srinivasan, who is now at the Pacific Ecoinformatics and Computational Ecology (PEaCE) Lab in Berkeley. "To our knowledge, our study is the first to really examine where nations' ecological footprints are falling, and it is an interesting contrast to the wealth of nations."Srinivasan, Norgaard and their colleagues reported their results this week in the early online edition of the journal Proceedings of the National Academy of Sciences."In the past half century, humanity has transformed our natural environment at an unprecedented speed and scale," Srinivasan said, noting that the Earth's population doubled in the past 50 years to 6.5 billion as the average per-capita gross world product also doubled. "What we don't know is which nations around the world are really driving the ecological damages and which are paying the price."Norgaard said that the largest environmental impact by far is from climate change, which has been assessed in previous studies. The current study broadens the assessment to include other significant human activities with environmental costs and thus provides a context for the earlier studies.The study makes clear, for example, that while deforestation and agricultural intensification primarily impact the host country, the impacts from climate change and ozone depletion are spread widely over all nations."Low-income countries will bear significant burdens from climate change and ozone depletion. But these environmental problems have been overwhelmingly driven by emission of greenhouse gases and ozone-depleting chemicals by the rest of the world," Srinivasan said.Climate change is expected to increase the severity of storms and extreme weather, including prolonged droughts and flooding, with an increase in infectious diseases. Ozone depletion mostly impacts health, with increases expected in cancer rates, cataracts and blindness All of these will affect vulnerable low-income countries disproportionately.In addition to climate change and ozone depletion, overfishing and conversion of mangrove swamps to shrimp farming are areas in which rich nations burden poor countries."Seafood derived from depleted fish stocks in low-income country waters ultimately ends up on the plates of consumers in middle-income and rich countries," Srinivasan said. "The situation is similar for farmed shrimp. For such a small, rare habitat, mangroves, when cut down, exact a surprisingly large cost borne primarily by the poor- and middle-income countries."The primary cost is loss of storm protection, which some say was a major factor in the huge loss of life from 2005's tsunami in Southeast Asia.Deforestation, on the other hand, can exacerbate flooding and soil erosion, affect the water cycle and offshore fisheries and lead to the loss of recreation and of non-timber products such as latex and food sources. Agricultural intensification can lead to drinking water contamination by pesticides and fertilizers, pollution of streams, salinization of croplands and biodiversity loss, among other impacts.When all these impacts are added up, the portion of the footprint of high-income nations that is falling on the low-income countries is greater than the financial debt recognized for low income countries, which has a net present value of 1.8 trillion in 2005 international dollars, Srinivasan said. (International dollars are U.S. dollars adjusted to account for the different purchasing power of different currencies.) "The ecological debt could more than offset the financial debt of low-income nations," she said.Interestingly, middle-income nations may have an impact on poor nations that is equivalent to the impact of rich nations, the study shows. While poor nations impact other income tiers also, their effect on rich nations is less than a third of the impact that the rich have on the poor.Norgaard admits that "there will be a lot of controversy about whether you can even do this kind of study and whether we did it right. A lot of that will just be trying to blindside the study, to not think about it. What we really want to do is challenge people to think about it. And if anything, if you don't believe it, do it yourself and do it better."Srinivasan led the three-year study in collaboration with Norgaard, who provided economic expertise; John Harte, professor of energy and resources at UC Berkeley, who initiated the idea and the basic framework for the study; post-doctoral fellow Susan Carey of the UC Berkeley Department of Environmental Science, Policy and Management; Reg Watson, a senior research fellow at the Fisheries Centre at the University of British Columbia; UC Berkeley Energy and Resources Group graduate students Adam B Smith, Amber C. Kerr, Laura E. Koteen and Eric Hallstein; and former UC Berkeley post-doctoral fellow Paul A. T. Higgins, who is now at the American Meteorological Society in Washington, D.C.

Ozone Holes

January 4, 2008

https://www.sciencedaily.com/releases/2008/01/080103135757.htm

Carbon Dioxide Emissions Linked To Human Mortality

A Stanford scientist has spelled out for the first time the direct links between increased levels of carbon dioxide in the atmosphere and increases in human mortality, using a state-of-the-art computer model of the atmosphere that incorporates scores of physical and chemical environmental processes. The new findings  come to light just after the Environmental Protection Agency's recent ruling against states setting specific emission standards for this greenhouse gas based in part on the lack of data showing the link between carbon dioxide emissions and their health effects.

While it has long been known that carbon dioxide emissions contribute to climate change, the new study details how for each increase of one degree Celsius caused by carbon dioxide, the resulting air pollution would lead annually to about a thousand additional deaths and many more cases of respiratory illness and asthma in the United States, according to the paper by Mark Jacobson, a professor of civil and environmental engineering at Stanford. Worldwide, upward of 20,000 air-pollution-related deaths per year per degree Celsius may be due to this greenhouse gas."This is a cause and effect relationship, not just a correlation," said Jacobson of his study, which on Dec. 24 was accepted for publication in Geophysical Research Letters. "The study is the first specifically to isolate carbon dioxide's effect from that of other global-warming agents and to find quantitatively that chemical and meteorological changes due to carbon dioxide itself increase mortality due to increased ozone, particles and carcinogens in the air."Jacobson said that the research has particular implications for California. This study finds that the effects of carbon dioxide's warming are most significant where the pollution is already severe. Given that California is home to six of the 10 U.S. cities with the worst air quality, the state is likely to bear an increasingly disproportionate burden of death if no new restrictions are placed on carbon dioxide emissions.On Dec. 19, the Environmental Protection Agency denied California and 16 other states a waiver that would have allowed the states to set their own emission standards for carbon dioxide, which are not currently regulated. The EPA denied the waiver partly on the grounds that no special circumstances existed to warrant an exception for the states.Stephen L. Johnson, the EPA administrator, was widely quoted as saying that California's petition was denied because the state had failed to prove the "extraordinary and compelling conditions" required to qualify for a waiver. While previous published research has focused on the global effect on pollution--but not health--of all the greenhouse gases combined, the EPA noted that, under the Clean Air Act, it has to be shown that there is a reasonable anticipation of a specific pollutant endangering public health in the United States for the agency to regulate that pollutant.Jacobson's paper offers concrete evidence that California is facing a particularly dire situation if carbon dioxide emissions increase. "With six of the 10 most polluted cities in the nation being in California, that alone creates a special circumstance for the state," he said, explaining that the health-related effects of carbon dioxide emissions are most pronounced in areas that already have significant pollution. As such, increased warming due to carbon dioxide will worsen people's health in those cities at a much faster clip than elsewhere in the nation.According to Jacobson, more than 30 percent of the 1,000 excess deaths (mean death rate value) due to each degree Celsius increase caused by carbon dioxide occurred in California, which has a population of about 12 percent of the United States. This indicates a much higher effect of carbon dioxide-induced warming on California health than that of the nation as a whole.Jacobson added that much of the population of the United States already has been directly affected by climate change through the air they have inhaled over the last few decades and that, of course, the health effects would grow worse if temperatures continue to rise.Jacobson's work stands apart from previous research in that it uses a computer model of the atmosphere that takes into account many feedbacks between climate change and air pollution not considered in previous studies. Developed by Jacobson over the last 18 years, it is considered by many to be the most complex and complete atmospheric model worldwide. It incorporates principles of gas and particle emissions and transport, gas chemistry, particle production and evolution, ocean processes, soil processes, and the atmospheric effects of rain, winds, sunlight, heat and clouds, among other factors.For this study, Jacobson used the computer model to determine the amounts of ozone and airborne particles that result from temperature increases, caused by increases in carbon dioxide emissions. Ozone causes and worsens respiratory and cardiovascular illnesses, emphysema and asthma, and many published studies have associated increased ozone with higher mortality. "[Ozone] is a very corrosive gas, it erodes rubber and statues," Jacobson said. "It cracks tires. So you can imagine what it does to your lungs in high enough concentrations." Particles are responsible for cardiovascular and respiratory illness and asthma.Jacobson arrived at his results of the impact of carbon dioxide globally and, at higher resolution, over the United States by modeling the changes that would occur when all current human and natural gas and particle emissions were considered versus considering all such emissions except human-emitted carbon dioxide.Jacobson simultaneously calculated the effects of increasing temperatures on pollution. He observed two important effects:Interestingly, neither effect was so important under the low pollution conditions typical of rural regions, though other factors, such as higher organic gas emissions from vegetation, affected ozone in low-pollution areas. Higher emissions of organic gases also increased the quantity of particles in the air, as organic gases can chemically react to form particles.And in general, where there was an increase in water vapor, particles that were present became more deadly, as they swelled from absorption of water. "That added moisture allows other gases to dissolve in the particles--certain acid gases, like nitric acid, sulfuric acid and hydrochloric acid," Jacobson said. That increases the toxicity of the particles, which are already a harmful component of air pollution.Jacobson also found that air temperatures rose more rapidly due to carbon dioxide than did ground temperatures, changing the vertical temperature profile, which decreased pollution dispersion, thereby concentrating particles near where they formed.In the final stage of the study, Jacobson used the computer model to factor in the spatially varying population of the United States with the health effects that have been demonstrated to be associated with the aforementioned pollutants."The simulations accounted for the changes in ozone and particles through chemistry, transport, clouds, emissions and other processes that affect pollution," Jacobson said. "Carbon dioxide definitely caused these changes, because that was the only input that was varied.""Ultimately, you inhale a greater abundance of deleterious chemicals due to carbon dioxide and the climate change associated with it, and the link appears quite solid," he said. "The logical next step is to reduce carbon dioxide: That would reduce its warming effect and improve the health of people in the U.S. and around the world who are currently suffering from air pollution health problems associated with it."

Ozone Holes

December 19, 2007

https://www.sciencedaily.com/releases/2007/12/071217141419.htm

Catching Polluters Made Easier With NASA Satellite Data

Detecting pollution, like catching criminals, requires evidence and witnesses; but on the scale of countries, continents and oceans, having enough detectors is easier said than done.

A team of air quality modelers, climatologists and air policy specialists at Arizona State University may soon change that. Under a grant from the Environmental Protection Agency, they have developed a new way to close the gaps in the global pollution dragnet by using NASA satellite data to detect precursors to ozone pollution, also known as smog. The technique, devised with the aid of health specialists from University of California at Berkeley, uses satellite data to improve ASU's existing computer models of ozone events -- filling in the blanks while expanding coverage to much larger areas. "The satellite data provides information about remote locations," said Rick Van Schoik, director of ASU's North American Center for Transborder Studies. "It gives us data from oceans and about events from other countries with less advanced monitoring capabilities, such as Mexico."Such information can have vital implications for health, especially in southern Arizona. According to Joe Fernando, a professor in ASU's department of mechanical and aerospace engineering and the environmental fluid dynamics program, who worked on the project, ozone is a key ingredient in urban smog, which affects even healthy adults and presents a special health risk to small children, the elderly and those with lung ailments. It can cause shortness of breath, chest pains, increased risk of infection, aggravation of asthma and significant decreases in lung function. Some studies have linked ozone exposure with death by stroke, premature death among people with severe asthma, cardiac birth defects and reduced lung-function growth in children.This new satellite-assisted model could allow researchers to see an ozone plume forming and work with communities to head off health effects in advance."Before, if there were precursors of an ozone event, we couldn't see them -- we just got hit by the pollution," Van Schoik said. "Now, we can watch the event build."Improved oceanic coverage could also help with monitoring one of the largest sources of pollution along the coasts: oceanic ships, which are covered only by international treaties and are not regulated by the EPA.Ozone forms when nitrogen oxides and volatile organic hydrocarbons -- byproducts of fossil fuel pollution -- react with one another in the presence of sunlight and warm temperatures, resulting in a chain reaction. This chain reaction can mean that large amounts of ozone can bloom from even moderate amounts of nitrogen oxides. Scientists can detect ozone by detecting the absorption of specific wavelengths of light, but they have had to rely on ground data and radiosondes -- atmospheric instrumentation bundles sent up on weather balloons -- to surmount the large uncertainties associated with the technique. "This is the reason comparisons were made between low-level ozone direct measurements with those obtained from satellites," said Fernando. "The importance is that the satellite data were used to improve model performance -- that this work will lead to better model predictions and hence superior forecasting of ozone and improved health warnings."The satellites currently provide data every 16 days. Each square, or pixel, of the grid they cover is five by eight kilometers, but Van Schoik said that the resolution would continue to improve. "NASA has developed tools that are starting to fulfill much of the promise that we hoped for when NASA began engaging in global environmental monitoring," he said. "With each member of our team adding their own expertise, we are seeing just how powerful that can be."

Ozone Holes

December 12, 2007

https://www.sciencedaily.com/releases/2007/12/071210103955.htm

Nitrous Oxide From Ocean Microbes Could Be Adding To Global Warming

A large amount of the greenhouse gas nitrous oxide is produced by bacteria in the oxygen poor parts of the ocean using nitrites according to Dr Mark Trimmer of Queen Mary, University of London.

Dr Trimmer looked at nitrous oxide production in the Arabian Sea, which accounts for up to 18 % of global ocean emissions. He found that the gas is primarily produced by bacteria trying to make nitrogen gas."A third of the 'denitrification' that happens in the world's oceans occurs in the Arabian Sea (an area equivalent to France and Germany combined)" said Dr Trimmer. "Oxygen levels decrease as you go deeper into the sea. At around 130 metres there is what we call an oxygen minimum zone where oxygen is low or non-existent. Bacteria that produce nitrous oxide do well at this depth."Gas produced at this depth could escape to the atmosphere. Nitrous oxide is a powerful greenhouse gas some 300 times more so than carbon dioxide, it also attacks the ozone layer and causes acid rain."Recent reports suggest increased export of organic material from the surface layers of the ocean under increased atmospheric carbon dioxide levels. This could cause an expansion of the oxygen minimum zones of the world triggering ever greater emissions of nitrous oxide."

Ozone Holes

November 7, 2007

https://www.sciencedaily.com/releases/2007/11/071105103936.htm

Hidden Details of Earth's Atmosphere Revealed By Orbiting Spacecraft

Watching the stars set from the surface of the Earth may be a romantic pastime but when a spacecraft does it from orbit, it can reveal hidden details about a planet’s atmosphere.

The technique is known as stellar occultation. Jean-Loup Bertaux, Service d'Aeronomie du CNRS, France was the first to suggest its use on an ESA mission. It works by watching stars from space, while they drop behind the atmosphere of a planet under investigation, before disappearing from view below the planet’s horizon.When the stars are shining above the atmosphere, they give off radiation across a wide spread of wavelengths. As the orbit of the spacecraft carries it around the planet, the star appears to sink down, behind the atmosphere of the planet. The atmosphere acts as a filter, blocking out certain wavelengths of the star’s radiation. The key to this technique is that the blocked wavelengths are representative of the molecules and atoms in the planet’s atmosphere.ESA currently has three spacecraft around three different planets that are using the technique to investigate those atmospheres. Each one is returning unique insights. Around Earth, ESA’s Envisat mission carries an instrument called GOMOS (Global Ozone Monitoring by Occultation of Stars). As its name suggests, it is designed to study whether the quantity of ozone is increasing now that the use of harmful chemicals has been banned. Since 2002, it has been watching about 400 stars set behind the Earth every day in order to build up a map of the ozone in the Earth’s atmosphere for all latitudes and longitudes.“It’s still too early to say whether the ozone is recovering or not,” says Bertaux. Nevertheless, as data accumulates, so the instrument is discovering other phenomena that contribute to the amount of ozone in the atmosphere. In January and February of 2004, GOMOS saw a large build up of nitrogen dioxide at an altitude of 65 km.Nitrogen dioxide is an important gas to trace in the atmosphere because it can destroy ozone. Over the next two months, GOMOS watched as the layer sank to 45 km, clearly destroying ozone as it descended, providing scientists with another piece in the ozone puzzle.A simplified stellar occultation instrument is onboard ESA’s Mars Express. Since the spacecraft arrived at the Red Planet in 2003, SPICAM (Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars) has observed more than 1000 stellar occultations. This work provides the most detailed description yet of Mars’s upper atmosphere, and reveals persistent haze layers.Apart from delivering pure science, the data provides practical benefits for future exploration missions. “Atmospheric profiles of Mars are important for designing parachutes for landing craft,” says Bertaux.The latest addition to this family of instruments is SPICAV (Spectroscopy for Investigation of Characteristics of the Atmosphere of Venus) on Venus Express. Venus has a different atmosphere again from Earth or Mars. It is much denser and SPICAV is revealing the temperature and density profiles of the atmosphere to waiting scientists on Earth, who expect to publish their results soon.“I think the stellar occultation technique is now ‘combat proven’ and should be useful for further long-term studies,” says Bertaux.The article reflects results from two publications. 'Stellar Occultations at UV wavelengths by the SPICAM instrument: Retrieval and analysis of Martian haze profile' by F. Montmessin, J.L. Bertaux and P. Rannou was published in the Journal of Geophysical Research in 2006. The second article 'Large increase of NO

Ozone Holes

October 29, 2007

https://www.sciencedaily.com/releases/2007/10/071027203000.htm

Human-generated Ozone Will Damage Crops, Reduce Production

A novel MIT study concludes that increasing levels of ozone due to the growing use of fossil fuels will damage global vegetation, resulting in serious costs to the world's economy.

The analysis, reported in the November issue of Energy Policy, focused on how three environmental changes (increases in temperature, carbon dioxide and ozone) associated with human activity will affect crops, pastures and forests. The research shows that increases in temperature and in carbon dioxide may actually benefit vegetation, especially in northern temperate regions. However, those benefits may be more than offset by the detrimental effects of increases in ozone, notably on crops. Ozone is a form of oxygen that is an atmospheric pollutant at ground level.The economic cost of the damage will be moderated by changes in land use and by agricultural trade, with some regions more able to adapt than others. But the overall economic consequences will be considerable. According to the analysis, if nothing is done, by 2100 the global value of crop production will fall by 10 to 12 percent."Even assuming that best-practice technology for controlling ozone is adopted worldwide, we see rapidly rising ozone concentrations in the coming decades," said John M. Reilly, associate director of the MIT Joint Program on the Science and Policy of Global Change. "That result is both surprising and worrisome."While others have looked at how changes in climate and in carbon dioxide concentrations may affect vegetation, Reilly and colleagues added to that mix changes in tropospheric ozone. Moreover, they looked at the combined impact of all three environmental "stressors" at once. (Changes in ecosystems and human health and other impacts of potential concern are outside the scope of this study.)They performed their analysis using the MIT Integrated Global Systems Model, which combines linked state-of-the-art economic, climate and agricultural computer models to project emissions of greenhouse gases and ozone precursors based on human activity and natural systems. Results for the impacts of climate change and rising carbon dioxide concentrations (assuming business as usual, with no emissions restrictions) brought few surprises. For example, the estimated carbon dioxide and temperature increases would benefit vegetation in much of the world. The effects of ozone are decidedly different.Without emissions restrictions, growing fuel combustion worldwide will push global average ozone up 50 percent by 2100. That increase will have a disproportionately large impact on vegetation because ozone concentrations in many locations will rise above the critical level where adverse effects are observed in plants and ecosystems.Crops are hardest hit. Model predictions show that ozone levels tend to be highest in regions where crops are grown. In addition, crops are particularly sensitive to ozone, in part because they are fertilized. "When crops are fertilized, their stomata open up, and they suck in more air. And the more air they suck in, the more ozone damage occurs," said Reilly. "It's a little like going out and exercising really hard on a high-ozone day." What is the net effect of the three environmental changes? Without emissions restrictions, yields from forests and pastures decline slightly or even increase because of the climate and carbon dioxide effects. But crop yields fall by nearly 40 percent worldwide.However, those yield losses do not translate directly into economic losses. According to the economic model, the world adapts by allocating more land to crops. That adaptation, however, comes at a cost. The use of additional resources brings a global economic loss of 10-12 percent of the total value of crop production.Global estimates do not tell the whole story, however, as regional impacts vary significantly. For example, northern temperate regions generally benefit from climate change because higher temperatures extend their growing season. However, the crop losses associated with high ozone concentrations will be significant. In contrast, the tropics, already warm, do not benefit from further warming, but they are not as hard hit by ozone damage because ozone-precursor emissions are lower in the tropics. The net result: regions such as the United States, China and Europe would need to import food, and supplying those imports would be a benefit to tropical countries.Reilly warns that the study's climate projections may be overly optimistic. The researchers are now incorporating a more realistic climate simulation into their analysis.Reilly's colleagues are from MIT and the Marine Biological Laboratory. The research was supported by the Department of Energy, the Environmental Protection Agency, the National Science Foundation, NASA, the National Oceanographic and Atmospheric Administration and the MIT Joint Program on the Science and Policy of Global Change.

Ozone Holes

October 23, 2007

https://www.sciencedaily.com/releases/2007/10/071022094516.htm

Space Sensors Reveal Air Pollution Sources

Air pollution is becoming one of the biggest dangers for the future of the planet, causing premature deaths of humans and damaging flora and fauna. With their vantage point from space, satellites are the only way to carry out effective global measurements of air-polluting emissions and their transboundary movement.

Scientists and researchers from around the world gathered at ESRIN, ESA’s Earth Observation Centre in Frascati, Italy, recently to discuss the contribution of satellite data in monitoring nitrogen dioxide in the atmosphere and to present the latest results of their ongoing atmospheric research that includes identifying hotspots, analysing trends and monitoring the effectiveness of mitigation efforts.All of the satellite data used by the participants was acquired through the TEMIS project, part of ESA’s Data User Programme (DUP). The TEMIS Internet-based service offers near-real time data products, long-term data sets and forecasts from various satellite instruments related to tropospheric trace gas concentrations, aerosol and Ultra Violet radiation. Emissions of gaseous pollutants have increased in India over the past two decades. According to Dr Sachin Ghude of the Indian Institute of Tropical Meteorology (IITM), rapid industrialisation, urbanisation and traffic growth are most likely responsible for the increase. Because of varying consumption patterns and growth rates, the distribution of emissions vary widely across India. In order to mitigate the causes of pollution, policy makers need to know the hardest hit regions.Using nitrogen dioxide (NO "Nitrous oxide emissions over India is growing at an annual rate of 5.5 percent/year and the location of emission hot spots correlates well with the location of mega thermal power plants, mega cities, urban and industrial regions," Ghude said. "Data from the 11-year time series of GOME and SCIAMACHY provide valuable information to improve estimates of nitrogen dioxide emissions as well as to identify the source regions and to study the regional ozone chemistry in light of seasonal meteorology." Because of the near-real time aspect of the TEMIS service, Yuxuan Wang, lecturer and research assistant at Harvard University, was able to obtain accurate measurements of the air quality over China during a traffic restriction using data from the Ozone Monitoring Instrument (OMI) instrument on NASA’s Aura satellite. Between 4 and 6 November 2006, 30 percent – or 800 000 – of Beijing's 2.82 million private vehicles were taken off the streets to facilitate organisation for the China-African summit and to perform a trial for the 2008 Olympic Games. By comparing the satellite observations with ground measurements and a global chemical transport model, Wang and her colleagues learned that the model did not capture the full amount of decrease in NO "Because the satellites witnessed this event, we could draw a quantitative analysis of how much reduction happened by using this independent dataset. We saw a 40 percent reduction in nitrogen dioxide emissions," Wang said. "TEMIS offers near real time data, allowing me to see daily measurements over Beijing with about a 2-hour time lag. When our group knows about traffic restrictions, we just go to the TEMIS website, download the data from that day and see whether there is a reduction in emissions picked up by satellites," she continued. "TEMIS, which allows very easy and open data access, is a big contribution of ESA to the whole community, not only for the European users but across the world, especially for places without in situ measurements."Simon Hales, Senior Research Fellow at the University of Otaga in New Zealand, is using satellite data from TEMIS to look at seasonal patterns of heart disease in New Zealand for the National Heart Foundation and to assess the global burden of disease related to air pollution. "The big advantage of using satellite data from the point of view of public health is that it gives us spatially extensive coverage that we do not get any other way," he explained. "Because newer instruments like SCIAMACHY and OMI are able to approximate some of the vertical profiles of NOBy using NO The service providers are currently planning to expand the existing TEMIS service to monitor the transboundary and hemispheric movement of air pollution.

Ozone Holes

October 22, 2007

https://www.sciencedaily.com/releases/2007/10/071021114804.htm

Antarctic Ozone Hole Shrinking Because Of Mild Weather, Not Recovery

Although the ozone layer over the Antarctic this year is relatively small, this is due to mild temperatures in the region’s stratosphere this winter and is not a sign of recovery, the United Nations World Meteorological Organization (WMO) has said.

Since 1998, only the ozone holes of 2002 and 2004 have been smaller than this year’s – both in terms of area and amount of destroyed ozone – and this is not indicative of ozone recuperation, the agency said.Instead, it is due to mild temperatures in the stratosphere, which still contains sufficient chlorine and bromine to completely destroy ozone in the 14-21 kilometer altitude range. The amount of gases which diminish ozone in the Antarctic stratosphere peaked around the year 2000. However, despite the decline in the amount by 1 per cent annually, enough chlorine and bromine will be in the stratosphere for another decade or two, which could result in severe ozone holes, WMO said. The size of the ozone hole will also be determined by the stratosphere’s meteorological conditions during the Antarctic winter. As greenhouse gases accumulate in the atmosphere, temperatures will fall in the stratosphere, increasing the threat of severe ozone holes in the future.

Ozone Holes

October 4, 2007

https://www.sciencedaily.com/releases/2007/10/071003100537.htm

2007 Ozone Hole 'Smaller Than Usual'

The ozone hole over Antarctica has shrunk 30 percent as compared to last year's record size. According to measurements made by ESA’s Envisat satellite, this year’s ozone loss peaked at 27.7 million tonnes, compared to the 2006 record ozone loss of 40 million tonnes.

Ozone loss is derived by measuring the area and the depth of the ozone hole. The area of this year’s ozone hole – where the ozone measures less than 220 Dobson Units – is 24.7 million sq km, roughly the size of North America, and the minimum value of the ozone layer is around 120 Dobson Units. A Dobson Unit is a unit of measurement that describes the thickness of the ozone layer in a column directly above the location being measured. For instance, if an ozone column of 300 Dobson Units is compressed to 0º C and 1 atmosphere (the pressure at the Earth’s surface) and spread out evenly over the area, it would form a slab of ozone approximately 3mm thick. Scientists say this year’s smaller hole – a thinning in the ozone layer over the South Pole – is due to natural variations in temperature and atmospheric dynamics (illustrated in the time series to the right) and is not indicative of a long-term trend. "Although the hole is somewhat smaller than usual, we cannot conclude from this that the ozone layer is recovering already,” Ronald van der A, a senior project scientist at Royal Dutch Meteorological Institute (KNMI), said. "This year's ozone hole was less centred on the South Pole as in other years, which allowed it to mix with warmer air, reducing the growth of the hole because ozone is depleted at temperatures less than -78 degrees Celsius." During the southern hemisphere winter, the atmospheric mass above the Antarctic continent is kept cut off from exchanges with mid-latitude air by prevailing winds known as the polar vortex. This leads to very low temperatures, and in the cold and continuous darkness of this season, polar stratospheric clouds are formed that contain chlorine. As the polar spring arrives, the combination of returning sunlight and the presence of polar stratospheric clouds leads to splitting of chlorine compounds into highly ozone-reactive radicals that break ozone down into individual oxygen molecules. A single molecule of chlorine has the potential to break down thousands of molecules of ozone. The ozone hole, first recognised in 1985, typically persists until November or December, when the winds surrounding the South Pole (polar vortex) weaken, and ozone-poor air inside the vortex is mixed with ozone-rich air outside it. KNMI uses data from Envisat's Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) instrument to generate daily global ozone analyses and nine-day ozone forecasts.Ozone is a protective layer found about 25 km above us mostly in the stratospheric stratum of the atmosphere that acts as a sunlight filter shielding life on Earth from harmful ultraviolet rays. Over the last decade the ozone layer has thinned by about 0.3% per year on a global scale, increasing the risk of skin cancer, cataracts and harm to marine life. The thinning of the ozone is caused by the presence of ozone destructing gases in the atmosphere such as chlorine and bromine, originating from man-made products like chlorofluorocarbons (CFCs), which have still not vanished from the air but are on the decline as they are banned under the Montreal Protocol, which was signed on 16 September 1987. Envisat can localise ozone depletion and track its changes, enabling the rapid estimation of UV radiation as well as providing forecasting. The three atmospheric instruments aboard Envisat are SCIAMACHY, the global ozone monitoring by occultation of stars (GOMOS) sensor and the Michelson interferometer for passive atmospheric sounding (MIPAS). ESA data form the basis of an operational near-real time ozone monitoring and forecasting service forming part of the PROMOTE (PROtocol MOniToring for the GMES (Global Monitoring for Environment and Security) Service Element) consortium, made up of more than 30 partners from 11 countries, including KNMI. As part of the PROMOTE and TEMIS service, the satellite results are combined with meteorological data and wind field models so that robust ozone and UV index forecasts can be made. GMES responds to Europe’s needs for geo-spatial information services by bringing together the capacity of Europe to collect and manage data and information on the environment and civil security, for the benefit of European citizens. The GMES Service Element (GSE) has been preparing user organisations in Europe and worldwide for GMES by enabling them to receive and evaluate information services derived from existing Earth Observation satellites since 2002.

Ozone Holes

October 3, 2007

https://www.sciencedaily.com/releases/2007/09/070930083243.htm

Ozone Shuts Down Early Immune Response In Lungs And Body

As policy makers debate what levels of ozone in the air are safe for humans to breathe, studies in mice are revealing that the inhaled pollutant impairs the body's first line of defense, making it more susceptible to subsequent foreign invaders, such as bacteria.

While it has long been known that exposure to ozone, a major component of urban air pollution, is associated with increased cardiovascular and pulmonary hospitalizations and deaths, the actual mechanisms involved remain unclear. New studies by Duke University Medical Center pulmonary researchers on the effects of ozone on the innate immune system, the body's "tripwire" for foreign invaders, may provide part of the answer.The Duke-led team found that ozone exposure in mice at levels approximating unhealthy levels for humans appears to enhance lung injury in response to bacterial toxins, but more importantly, it also appears to enhance programmed cell death in critical innate immune system cells that gobble up foreign invaders, keeping the airways clear."Small amounts of inhaled foreign material can be relatively harmless, since they stimulate an appropriate innate immune response that protects the lungs," said John Hollingsworth, M.D., pulmonologist and lead author of study whose results appear Oct. 1 in the Journal of Immunology. "However, it appears that ozone causes the innate immune system to overreact, killing key immune system cells, and possibly making the lung more susceptible to subsequent invaders, such as bacteria."The innate immune system is the most primitive aspect of the body's defenses. Its cells react indiscriminately to any invader. One of the key cells in the innate immune system is known as a macrophage, Greek for "big eater."For their experiments, the researchers had mice breathe either room air or air with levels of ozone meant to mirror what an exercising human would experience on a high, or unhealthy, ozone level day. After exposing all mice to the active portion of E. coli bacteria in aerosol form, the researchers studied how the innate immune system responded."In the mice exposed to ozone, the airways of the lungs were hyperactive and we found higher concentrations of inflammatory cells," Hollingsworth said. "But more significantly, ozone pre-exposure reduced the number of macrophages in the lung after secondary exposure to inhaled bacterial endotoxin. Exposure to ozone in this context had stimulated them to undergo programmed cell death, or apoptosis."The researchers also found that the effect of the inhaled ozone was not limited to just the lungs. Mice exposed to ozone were also found to have lower levels of immune system cells circulating in the blood.The Duke team plans further studies on the mechanisms behind ozone's ability to induce cell death in macrophages in the lungs. They will also focus on the pollutant's ability to interfere with system-wide immune responses.The Environmental Protection Agency is in the final phases of reviewing and possibly updating the standards for allowable levels of ozone in the air. The current standard says that any amount greater than 85 parts per billion can be unhealthy for those at risk. Many medical groups, including the American Thoracic Society, recommend setting a stricter standard of 60 parts per billion, citing studies showing ozone's adverse effects on health, especially in children and those with compromised health.Hollingsworth's research was supported by the National Institutes of Health. Duke members of the team included Zhuowei Li, Erin Potts, and W. Michael Foster. Other members were Alan Fong of the University of North Carolina -- Chapel Hill and National Institute of Environmental Health Sciences researchers Shuichiro Maruoka, Stavros Garantziotis, David Brass and David Schwartz.

Ozone Holes

September 24, 2007

https://www.sciencedaily.com/releases/2007/09/070919101715.htm

Scientists In First Global Study Of 'Poison' Gas In The Atmosphere

An international team used the Canadian Atmospheric Chemistry Experiment satellite to carry out the first global study of the atmospheric distribution of poisonous phosgene gas.

Phosgene gas was used as a chemical weapon in the trenches in the First World War, but nearly a century later, new research has discovered that phosgene is present in significant quantities in the atmosphere. Phosgene was still stockpiled in military arsenals well after the Second World War, but its continued presence in the atmosphere today is due to man-made chlorinated hydrocarbons used in the chemical industry. A team, including Professor Peter Bernath, of the Department of Chemistry at the University of York, has carried out the first study of the global distribution of the gas. The team also involved scientists from the Universities of Waterloo and Toronto in Canada, NASA’s Jet Propulsion Laboratory and the New Mexico Institute of Mining and Technology in the USA. Between February 2004 and May 2006, they used the Canadian Atmospheric Chemistry Experiment (ACE) satellite to measure the incidence of the gas. The research, which was financed by the Canada Space Agency (CSA) and the Natural Sciences and Engineering Research Council of Canada, is published in the latest edition of Geophysical Research Letters. The scientists discovered that the main atmospheric concentration of the gas was above the Equator, though it was present in some quantity in all latitudes. They found that levels of phosgene in the atmosphere had reduced since previous studies in the 1980s and 1990s, though its continued presence is a contributor to ozone depletion. Phosgene plays a major role in the preparation of pharmaceuticals, herbicides, insecticides, synthetic foams, resins and polymers, though its use is being reduced. Professor Bernath said: "There is a small, but not negligible, concentration of phosgene in the troposphere. Chlorinated hydrocarbons don't occur in nature but as chlorinated solvents they are used by industry. They are short-lived and they decay rapidly, but they decay into phosgene. "It's very toxic and pretty nasty stuff - its reputation is well deserved. Considering the health hazards associated with phosgene, the chemical industry is trying to find substitutes to eliminate its use. But the use of chlorinated hydrocarbons is being reduced because of the legal restrictions of the Montreal Protocol, so phosgene is also decreasing." Higher up in the atmosphere phosgene can be slowly oxidized by ultraviolet rays, and so it continues to play a role in the depletion of the ozone layer.

Ozone Holes

September 18, 2007

https://www.sciencedaily.com/releases/2007/09/070913181730.htm

NASA Keeps Eye On Ozone Layer Amid Montreal Protocol's Success

NASA scientists will join researchers from around the world to celebrate the 20th anniversary of the Montreal Protocol, an international treaty designed to reduce the hole in Earth's protective ozone layer.

The United Nations Environment Program will host the meeting from Sept. 23-26 in Athens, Greece. NASA scientists study climate change and research the timing of the recovery of the ozone layer."The Montreal Protocol has been a resounding success," said Richard Stolarski, a speaker at the symposium from NASA's Goddard Space Flight Center, Greenbelt, Md. "The effect can be seen in the leveling off of chlorine compounds in the atmosphere and the beginning of their decline."Since the Montreal Protocol was signed on Sept. 16, 1987, more than 100 nations have agreed to limit the production and release of compounds, notably human-produced chlorofluorocarbons, known as CFCs. CFCs and a list of other compounds are known to degrade the layer of ozone in the stratosphere that shields life from the sun's ultraviolet radiation. That process gives rise to the ozone hole above Antarctica.Today, space-based instruments aboard NASA's Aura satellite monitor the chemical make-up of the atmosphere and collect data that will help researchers better understand ozone chemistry through computer models. While the data show that average chlorine levels are beginning to decline, springtime ozone depletion in the polar regions continues to be a prominent atmospheric feature."The goal now is to ensure that CFCs and other emissions continue to fall to below the levels that produce an ozone hole," said Goddard's Anne Douglass, the deputy project scientist for Aura. "This won't happen until about 2070."NASA and National Oceanic and Atmospheric Administration scientists announced in 2006 that the hole was the largest ever observed, at 10.6 million square miles. The size of the hole will approach its annual peak in late September. Researchers at the symposium will discuss 20 years of scientific progress, as well as how best to monitor the atmosphere to ensure the goals of the treaty are realized. In addition to the current satellite measurements, NASA research efforts use data collected on the ground, in the air and from previous missions.Data from past satellite observations have been essential to understanding ozone depletion. NASA's Total Ozone Mapping Spectrometer, or TOMS, was one of NASA's signature ozone research achievements. TOMS launched in 1978 and was decommissioned in May 2007."The TOMS images of the Antarctic ozone hole caused worldwide alarm and thus played a key role in the Montreal Protocol and other international agreements to phase out the offending chemicals from our environment," said Goddard's Pawan Bhartia, project scientist for the mission. In addition, measurements from the Stratospheric Aerosol and Gas Experiment, along with the Microwave Limb Sounder and the Halogen Occultation Experiment aboard the Upper Atmospheric Research Satellite, were important to scientists' understanding of ozone. Scientists collect atmospheric composition data from ground-based monitoring stations around the world. Researchers have collected measurements since 1978 for nearly all compounds identified in the Montreal Protocol. The data come from coastal monitoring stations used in previous missions and as part of the NASA-sponsored Advanced Global Atmospheric Gases Experiment.Airborne instruments have been a critical piece of the scientific search to find the cause of ozone depletion, and they remain central to NASA's research efforts today. Data from NASA's Airborne Antarctic Ozone Experiment in 1987 "provided the smoking gun measurements that nailed down the cause of the ozone hole being the increase of CFCs combined with the unique meteorology of the Antarctic," Stolarski said. Since then, NASA has sponsored several airborne field campaigns that have furthered understanding of the chemical processes controlling ozone.These measurements are key for researchers working to predict the future of the global ozone layer. The differences between loss and recovery of ozone at the poles and in non-polar regions are complex. "Such complexity has led to heated debates over the timing and extent of recovery," said Ross Salawitch, an atmospheric chemist at the Jet Propulsion Laboratory, Pasadena, Calif. The modern focus in ozone research also has shifted to include the effects of climate change. "Twenty years ago we went out of our way to separate ozone depletion from climate change," Salawitch said. "After a decade of looking at data, the community realizes they are linked in subtle but profoundly important ways."

Ozone Holes

August 21, 2007

https://www.sciencedaily.com/releases/2007/08/070820175419.htm

Air Quality Study: Mercury and Formaldehyde Found In Houston, Texas Air

As a frequent addition to the list of America’s most polluted cities, Houston is no stranger to having more than just oxygen and carbon dioxide in the air. But a University of Houston study found a few surprising results in the air Houstonians breathe day in, day out: mercury and formaldehyde.

Although Houston’s air quality has improved from previous years, the Texas Air Quality Study-II, a 45-day study conducted in 2006, is the first to provide solid mercury measurements in Houston, according to Barry Lefer and Bernhard Rappenglueck, UH professors of atmospheric science.“Formaldehyde has been measured before in Houston’s air, but, to the best of my knowledge, mercury has not been measured in Houston,” Rappenglueck said. “There is now a significant amount of formaldehyde and mercury in the air here at times.”Scientists know mercury is emitted mostly from coal-burning power plants, such as the one in Sugar Land, but there is additional mercury coming from the area around the Houston Ship Channel and the nearby refineries and petrochemical plants, according to the study. The more than 100 scientists from UH and research institutions across the country who pored over the air quality data are still analyzing the information to identify what industrial processes are producing the mercury. Most of the data was collected from the UH Moody Tower Atmospheric Chemistry Facility, an 18-story building that is operational 24 hours a day, seven days a week, and from data collected from various aircrafts and a National Oceanic Atmospheric Administration ship in the Houston Ship Channel.The Moody Tower facility measured three different types of mercury: gaseous elemental mercury, reactive gaseous mercury and fine particulate mercury. Although traces of mercury have been found all over the country, the amounts detected varied from double to more than six times what is typically found in other parts of the United States, Lefer said.“Mercury is toxic and is most detrimental to children and pregnant women and causes developmental abnormalities,” Lefer said. “Mercury emissions from coal and other sources are going to be more problematic to reduce, but using cleaner fuels and alternative energy for electricity will reduce the mercury levels in the environment.”The base for embalming fluid, formaldehyde is believed to be the catalyst in the production of ozone, a harmful pollutant that may be primarily emitted from traffic and poorly maintained diesel cars, and secondarily by chemical reactions in the atmosphere.“Primary formaldehyde means it is directly emitted to the atmosphere,” Rappenglueck said. “Secondary formaldehyde means that it is chemically formed in the atmosphere from other chemicals.” Formaldehyde emissions from automobile exhaust are directly emitted into the atmosphere, but their contribution is small, Rappenglueck said. Instead, the air quality data suggests there may be a “new” source of primary formaldehyde emissions in Houston. “Once the source of the formaldehyde is identified, it should be possible to figure out how to reduce these emissions,” Lefer said. “Formaldehyde is not toxic at these levels, but it is very efficient at producing ozone pollution. We think this is one of the ‘missing’ links in understanding Houston’s ozone pollution.”The UH Atmospheric Science group is working on calculations to assess the impact of primary formaldehyde emissions in producing ozone in Houston. They hope to have the results in time for conferences in December and January.The Texas Air Quality Study-II wasn’t all doom and gloom for Houston, though. Houston does have a serious ozone problem, but efforts to fix it are headed in the right direction.“The bad news is that Houston’s ozone levels are above the Environmental Protection Agency’s (EPA) standards for 30 to 40 days each year,” Lefer said. “The EPA allows a city to have one to three ‘bad’ ozone days per year. So we are well above this average. But, the good news is that the number of ‘bad’ ozone days each year in Houston is decreasing. In addition, the peak ozone values observed in Houston have also been on a down trend the past six years. We still have a long way to go, though.”

Ozone Holes

August 16, 2007

https://www.sciencedaily.com/releases/2007/08/070815085429.htm

Air Pollution Linked To Cardiovascular Risk Indices In Healthy Young Adults

Researchers in Taiwan have demonstrated for the first time that urban air pollution simultaneously affects key indicators of cardiovascular risk in young adults: inflammation, oxidative stress, coagulation and autonomic dysfunction.

The study, which appeared in the second issue for August of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society, investigated the effect of common urban air pollutants on biological markers for inflammation, oxidative stress, coagulation and autonomic dysfunction in 76 healthy Taiwanese college students. The researchers collected blood samples and performed electrocardiograms on each subject approximately every 30 days for the months of April, May and June in either 2004 or 2005. They then correlated the sample dates and time with monitoring data from a fixed-site air monitoring station on the students' campus. The concentrations of common urban air pollutants were averaged over 24, 48 and 72 hours. They found significant increases in all indices of cardiovascular risk were associated with increased exposure to common pollutants. "This study provides evidence that urban air pollution is associated with systemic inflammation/oxidative stress, impairment of the fibrinogenic system, activation of blood coagulation and alterations in the autonomic nervous system in young, healthy humans," wrote the study's lead author Chang-Chuan Chan, Sc.D., of National Taiwan University's College of Public Health."Most pollution literature has shown affects in elderly people, and although there have been experiments in young subjects, epidemiological research has not found such significant effects in young people as with these students in Taiwan," said Benoit Nemery, M.D., Ph.D., professor in the division of pneumonology at the Catholic University of Leuvin in Belgium, who was not involved in the research.Specifically, the investigators found that increases in high-sensitivity C-reactive protein (hs-CRP) (an indicator of risk for a cardiovascular event), 8-hydroxy-2'-deoxyguanosine (8-OHdG) (a marker of oxidative stress), fibrinogen (a coagulation factor), plasminogen activator fibrinogen inhibitor-1 (PAI-1) (a marker of inflammation) and decreases in heart rate variability (HRV) (a predictor of increased cardiovascular risk) were associated with increases in particulate matter, sulfate, nitrate, and ozone when they analyzed pollutants singly, and that increases in 8-OHdG, fibrinogen, and PAI-1 and decreases HRV were correlated to increased ozone and sulfate levels over three day averages in multi-pollutant models.The precise biological mechanisms involved were not able to be determined with this study's design. "Further studies with more detailed measurements of cardiovascular endpoints over time are still needed to elucidate the time sequence of pollution effects on cardiovascular endpoints in humans," wrote Dr. Chang-Chuan Chan. "Many questions remain to be answered," wrote Joel Kaufman, M.D., M.P. H., in the accompanying editorial, "[But] these questions should by no means slow the important efforts to reduce exposures and benefit global public health."

Ozone Holes

July 27, 2007

https://www.sciencedaily.com/releases/2007/07/070726104756.htm

New Clues To Ozone Depletion

Large quantities of ozone-depleting chemicals have been discovered in the Antarctic atmosphere by researchers from the University of Leeds, the University of East Anglia, and the British Antarctic Survey.

The team of atmospheric chemists carried out an 18-month study of the make-up of the lowest part of the earth's atmosphere on the Brunt Ice Shelf, about 20 km from the Weddell Sea. They found high concentrations of halogens - bromine and iodine oxides -- which persist throughout the period when there is sunlight in Antarctica (August through May). A big surprise to the science team was the large quantities of iodine oxide, since this chemical has not been detected in the Arctic.The source of the halogens is natural -- sea-salt in the case of bromine, and in the case of iodine, almost certainly bright orange algae that coat the underside of the sea ice around the continent. These halogens cause a substantial depletion in ozone above the ice surface. This affects the so-called oxidising capacity of the atmosphere - its ability to "clean itself" by removing certain - often man-made - chemical compounds. The iodine oxides also form tiny particles (a few nanometres in size), which can grow to form ice clouds, with a consequent impact on the local climate.Scientists now plan to carry out further research to assess what impact this may be having on the local environment. Very recent satellite observations by one of the team, Dr Alfonso Saiz-Lopez, have confirmed that iodine oxides are widespread throughout coastal Antarctica.John Plane, professor of atmospheric chemistry at the University of Leeds, says: "Halogens in the lowest part of the atmosphere have important impacts on ozone depletion, the ability of the atmosphere to remove potentially harmful compounds, and aerosol formation. All these atmospheric phenomena are linked to climate change. We still have to work out what the ramifications of this discovery are. These exciting results also show how important it is to keep exploring the atmosphere - there seems to be plenty more to find out."Using high-tech measuring equipment, a beam of light was projected across the ice shelf and the spectrum of the reflected light analysed and chemical levels measured. The work was carried out in a new atmospheric observatory at Halley Station, operated by the British Antarctic Survey, and was supported by funding from the U.K.'s Natural Environment Research Council.The research was published by Science. 

Ozone Holes

July 27, 2007

https://www.sciencedaily.com/releases/2007/07/070725143612.htm

Rising Surface Ozone Reduces Plant Growth And Adds To Global Warming

Scientists from three leading UK research institutes have just released new findings that could have major implications for food production and global warming in the 21st century.

Experts from the Met Office, the University of Exeter and the Centre for Ecology & Hydrology, have found that projections of increasing ozone near the Earth's surface could lead to significant reductions in regional plant production and crop yields. Surface ozone also damages plants, affecting their ability to soak up carbon dioxide from the atmosphere and accelerating global warming. Near-surface ozone has doubled since 1850 due to chemical emissions from vehicles, industrial processes, and the burning of forests. Dr Stephen Sitch, a climate impacts scientist at the Met Office Hadley Centre and lead author of the article, said: "Climate models have largely ignored atmospheric chemistry but in this research we have identified a cause of potentially increased warming with elevated levels of surface ozone likely to suppress plant growth."Plants and soil are currently slowing--down global warming by storing about a quarter of human carbon dioxide emissions, but the new study suggests that this could be undermined by further increases in near-surface ozone. As a result more carbon dioxide would accumulate in the atmosphere and add to global warming. Co-author, Professor Peter Cox of the University of Exeter, explains: "We estimate that ozone effects on plants could double the importance of ozone increases in the lower atmosphere as a driver of climate change, so policies to limit increases in near-surface ozone must be seen as an even higher priority." The research is published online in Nature July  25, 2007.

Ozone Holes

July 24, 2007

https://www.sciencedaily.com/releases/2007/07/070720095943.htm

Drifting By Ice Floe To The North Pole

An eight-month voyage through the Arctic Ocean, without ship or travel route: the North Pole drifting station NP-35 represents an unusual project of the International Polar Year.

At the end of August the expedition, under Russian leadership, will leave for the Arctic Ocean. One of the participants is Jürgen Graeser of the Alfred Wegener Institute for Polar and Marine Research, one of the research centres of the Helmholtz Association. For the first time in the history of Russian research using drifting stations, a German researcher will take part in the North Pole drifting station NP-35. With his data recordings of the atmosphere, Graeser will supplement measurements carried out by the Russian project partners, who will be focusing their investigations on sea ice, primarily performing measurements close to the ice. Through this collaboration, the project partners intend to advance the currently patchy data situation in the Arctic and hope to gain a better understanding of these key regions for global climate change.  The planned project will be carried out in conjunction with the Arctic and Antarctic Research Institute (AARI) in St Petersburg. On August 29, 2007, a total of 36 expedition participants will board the Russian research vessel 'Akademik Fedorov' in the Siberian harbour of Tiksi. In the vicinity of Wrangel Island, i.e. between 80 and 85 degrees northern latitude and between 170 degrees eastern and 170 degrees western longitude, a stable ice floe will be chosen as the base for the drifting station 'North Pole 35' (NP-35). The selection will be based on long-term satellite observations of the ice and will be verified by helicopter from the research vessel. During the course of winter, the ice floe will drift in the Arctic Ocean and across the North Pole. During the drift, a variety of measurements carried out at the station will provide information about current climate change. The 'Akademik Fedorov' is scheduled to evacuate the station after approximately one year. With regard to over-wintering personnel, it is planned to use 'Polar 5', the research aircraft of the Alfred Wegener Institute, to fly out Jürgen Graeser and five Russian colleagues after approximately eight months, in April 2008. For this purpose, a landing strip will be constructed on the ice.The Russian colleagues will be investigating the upper ocean layer and sea ice, as well as snow cover. Atmospheric measurements of meteorological parameters such as temperature, wind, humidity and air pressure, will be added through recordings of trace gases such as carbon dioxide and ozone. Jürgen Graeser will examine two topics. On the one hand, he will use a captive balloon system to measure meteorological parameters in the so-called planetary boundary layer, which is the lowest layer of the atmosphere extending to approximately 1500 metres. In addition, he will use ozone sensors to measure the ozone layer in the stratosphere up to approximately 30 kilometres altitude.Jürgen Graeser has been a technician at the research unit Potsdam of the Alfred Wegener Institute and has many years of experience with Arctic and Antarctic expeditions. His special areas of interest are aerology and meteorology. His expertise includes balloon-based, radiation and meteorological measurements.The Arctic represents a key region for global climate change. Measurements of sea ice and atmospheric parameters in the Arctic Ocean are still incomplete. Through the current project, researchers intend to identify key processes in the atmosphere and alterations of the sea ice cover in order to examine the coupling of sea ice and atmosphere. The project is one of many during the International Polar Year. More than 50,000 scientists and technical staff from over 60 countries are joining force to explore the polar regions. Their goal is to study the role of the Arctic and Antarctic in shaping the climate and the earth's ecosystems.The planetary boundary layer (PBL) identifies the lowest atmospheric layer, extending from the surface to approximately 1500 metres altitude. In the Arctic, this layer is characterised by frequent temperature inversions, i.e. by very stable atmospheric stratification which suppresses vertical movements of the air. A realistic representation of the planetary boundary layer is crucial for the construction of climate models, as it is this layer that determines the lower marginal conditions for all calculations. Particularly, the investigation of processes influenced directly by the boundary layer, requires exact knowledge of the state of the PBL. AWI scientists in Potsdam use the regional climate model HIRHAM to construct mesoscale fields of pressure, temperature and wind in which cyclones (low pressure regions) and their trajectories are identified. Specifically, they are examining the relationship between cyclone development and various surface conditions (e.g. sea ice cover). Elucidating the connection between the Arctic planetary boundary layer and mesoscale cyclones and their trajectories is the goal of these investigations.Discovery of the Antarctic ozone hole in 1985 triggered intensive exploration efforts of the polar ozone layer. This layer is located between 15 and 25 kilometres altitude in the stratosphere. Many chemical processes of ozone depletion in the Antarctic have since been explained, and the connection of ozone destruction with anthropogenic emissions of chlorofluorocarbons (CFCs) and halons has been proven beyond doubt. During specific winters, severe ozone losses over the Arctic, and hence much closer to home, have already contributed to a reduction in ozone layer thickness over Europe -- leading to an increase of harmful ultraviolet radiation on the earth's surface. However, to date the ozone depletion in the Arctic is not as pronounced as over the Antarctic. Compared to the Arctic, ozone layer thickness in the Antarctic is much more variable, with only about half of the observed inter-annual variability explained by known chemical mechanisms. Hence, dynamic processes which remain only partly understood are equally important in determining thickness of the ozone layer over the Arctic as the chemical decomposition of ozone. At the Arctic station of the Alfred Wegener Institute in Ny Ålesund on Spitsbergen (79°N), for instance, a strong annual ozone variation of 30 percent was detected at an altitude of 25 to 30 kilometres. Apparently, it is synchronised with variability of the sun, but cannot be explained by known chemical or other dynamic processes. Investigating the cause of this variability will be the focus of ozone measurements at NP-35. Data records from the drifting station will, for the first time, produce high resolution vertical profiles of ozone distribution in the central Arctic, north of 82 degrees latitude -- currently a blank spot on the global ozone distribution map. These unique data will be combined with existing ozone profiles from the Arctic and Sub-Arctic. Calculations of air movement in conjunction with chemical models will contribute to an understanding of seasonal and annual variability of stratospheric ozone in the Arctic.

Ozone Holes

July 1, 2007

https://www.sciencedaily.com/releases/2007/06/070627161739.htm

NASA Expedition Will Examine Climate Change, Ozone In Tropics

A high-flying NASA mission over Costa Rica and Panama in July and August should help scientists better understand how tropical storms influence global warming and stratospheric ozone depletion, says a University of Colorado at Boulder professor who is one of two mission scientists for the massive field campaign.

Brian Toon, chair of CU-Boulder's atmospheric and oceanic sciences department, said the $12 million effort will mobilize in San Jose, Costa Rica, and involve about 400 scientists, students and support staff operating three NASA aircraft, seven satellites and a suite of other instruments. The team is targeting the gases and particles that flow out of the top of the vigorous storm systems that form over the warm tropical ocean, said Toon. The warm summer waters of the Pacific Ocean in Central and South America are a breeding ground for heat-driven convective storms targeted by the mission, said NASA officials. Such tropical systems are the major mechanism for Earth's system to loft air into the upper troposphere and stratosphere and are characterized primarily by cumulus clouds with large dense anvils and wispy cirrus clouds. Known as the Tropical Composition, Cloud and Climate Coupling mission, or TC4, The expedition runs from July 16 through Aug. 8 and is NASA's largest field campaign in several years. The tropical storm systems under study pump air more than 40,000 feet above the surface, where they can influence the make-up of the stratosphere, home of Earth's protective ozone layer. "This is a very little-studied region of the atmosphere, but it is crucial to understanding global climate change and changes in stratospheric ozone," Toon said. One mission goal is to understand how transport of chemical compounds - both natural and man-made - occurs from the surface to the lower stratosphere, which is roughly 10 miles in altitude. Another goal is to understand the properties of high-altitude clouds and how they impact Earth' s radiation budget, Toon said. As a TC4 mission scientist, Toon will be coordinating daily flights of three NASA aircraft filled with scientific instruments that will collect data in concert with NASA satellites. The aircraft include the ER-2 -- NASA's modern version of the Air Force U2-S reconnaissance aircraft -- which can reach an altitude of 70,000 feet and which will fly above the clouds and act as a "surrogate satellite," he said. The mission also includes a broad-winged WB-57 research plane that will fly into the cirrus clouds at 60,000 feet and sample cloud particles and the make-up of chemicals flowing from massive tropical storm systems. The third plane, a converted DC-8, will fly at about 35,000 feet to probe the region between Earth' s troposphere and stratosphere and sample cloud particles and air chemistry. "The critical lever in greenhouse warming is water in the upper troposphere," said Toon. "Added water, or more extensive clouds as a result of global warming, would significantly amplify the greenhouse effect from human made pollutants such as carbon dioxide." Conversely, more extensive convection due to rising sea-surface temperatures could lead to more precipitation and less cloud cover, acting to "retard" greenhouse warming, he said. Toon and his graduate students will be studying the size and role of ice particles in clouds to better understand how Earth might respond to warming temperatures. "We'd really like to understand the processes that control water as it is going into the stratosphere, which should help improve climate models," he said. Toon, who spent several years helping to design the NASA mission and chaired the committee that organized the effort, also will be working with CU-Boulder graduate student Charles Bardeen in San Jose on daily weather forecasts, which will help dictate when planes can safely sample in targeted atmospheric regions. Other participants from CU's oceanic and atmospheric sciences department, or ATOC, include Associate Professor Linnea Avallone, who will work with graduate students to sample water condensed in clouds. Associate Professor Peter Pilewskie and his students will study reflected sunlight from bright clouds to better understand Earth's energy budget in relation to climate change, while Research Associate Frank Evans will study ice cloud properties using radiometry. Scientists from CU-Boulder's Cooperative Institute for Research in Environmental Sciences -- a joint venture of CU-Boulder and the National Oceanic and Atmospheric Administration -- also will participate in the mission. CIRES and NOAA have 14 researchers involved in the TC4 mission from Boulder. Observations from a suite of NASA satellites flying in formation, known as the "A-Train," will complement the aircraft measurements. The satellites will measure ozone, water vapor, carbon monoxide and map clouds, charting the aerosol particles inside that affect their formation. "The potential economic repercussions of global warming are almost unimaginable," said Toon. "We could lose large fractions of entire states over the next century or so if there are significant increases in sea level. "This mission will help us understand Earth's systems and what happens when we modify the planet." Toon said NASA has a made a huge investment in its satellite fleet over the years and in finally implementing the TC4 mission. "NASA has a commitment to better understand these complex issues," he said. "And our graduate students will probably be writing theses on data from the TC4 mission for the next decade."

Ozone Holes

June 26, 2007

https://www.sciencedaily.com/releases/2007/06/070625131625.htm

Gender May Play Role In Recovery From Pneumonia After Ozone Exposure

Does air pollution have a bigger effect on the immune system of females than males? It did among mice exposed to ozone -- a major component in air pollution that is known to negatively affect lung function -- and then infected with pneumonia, as significantly more females died from the infection than males.

It is known that some immune functions differ in males and females, in humans as well as in rodents. Generally, scientists use male animals in their research to avoid the complicating influence of female hormones on study data. Hypotheses based on single-sex results, however, may miss critical pieces of information. The researchers believe this study, for example, suggests that air pollutants, such as ozone, have a significantly higher negative effect on females than on males and that consideration of the role of environmental pollutants on health should take gender into account."If we could extrapolate what we found to the human population, it would mean women with lung infections may be at higher risk for negative outcomes if they are exposed to high amounts of air pollution, and in particular, ozone," said Joanna Floros, Ph.D., Penn State College of Medicine professor of cellular and molecular physiology, pediatrics and obstetrics and gynecology, and the lead investigator on the study.More than 100 million people in the United States live in areas with ozone levels higher than recommended by the U.S. Environmental Protection Agency's air quality standards. Though ozone occurs naturally in the stratosphere and provides a protective layer high above the earth, it is the prime ingredient of smog at ground level. Smog is known to exacerbate respiratory problems.In the study, mice were exposed for three hours either to filtered air or to air with high levels of ozone. They then were infected with a pneumonia bacteria at a dosage that assured all mice would become sick with the disease. Researchers monitored the mice for two weeks and calculated survival rates.There were three obvious findings. First, the mice exposed to ozone before infection died more often than did mice that had breathed only filtered air.Second, ozone was even more damaging to one type of mouse, which was genetically engineered without the gene responsible for producing a "protective" or host defense protein called SP-A and had even higher mortality from pneumonia than did ordinary (wild-type) mice, after both groups were exposed to ozone. SP-A is a molecule that provides first-line defense in the lung against various inhaled irritants, bacteria, viruses, and pollen, and it is a component of a complex substance (called surfactant) that coats the tiny air sacs in the lung and prevents the lungs from collapsing.Third, ozone exposure significantly decreased the likelihood of surviving pneumonia exposure for the female mice compared to males. In both the wild-type mice and in the genetically altered mice, being female increased the risk of death.This research study, led by senior postdoctoral fellow Anatoly Mikerov, Ph.D., is ongoing. Some results were presented at the recent Experimental Biology Meeting. Support for this work came from the National Institute of Environmental Health Sciences.

Ozone Holes

June 22, 2007

https://www.sciencedaily.com/releases/2007/06/070621143648.htm

EPA Ozone Pollution Standards 'Unhealthy For America,' Says American Thoracic Society President

David H. Ingbar MD, president of the American Thoracic Society, today called the proposed standards issued by the Environmental Protection Agency for ozone pollution--commonly known as smog-"unhealthy for America's kids, unhealthy for America's seniors, and unhealthy for America."

"The science is clear," Dr. Ingbar said, "ozone pollution is causing unnecessary, illnesses and death in America. The proposed EPA standards fall short of providing the protection needed to keep Americans safe from ozone air pollution." In announcing the proposed standard today, EPA is calling for a modest tightening of the current standard of 0.08 ppm/8-hours. EPA is proposing a revised standard in the range of 0.075 ppm/8-hours to 0.070 ppm/8-hours. While suggesting a stricter standard, EPA is still considering retaining the current standard. The range proposed by the EPA falls far short of the standard of 0.060 ppm/8-hours supported by the American Thoracic Society and others in the scientific community.By failing to adopt a more stringent ozone standard, EPA is ignoring the strong scientific evidence that shows real harm being caused by ozone pollution at the current standard. "In issuing the standard today, EPA is ignoring the advice of their own staff, the advice of EPA advisory committees, the opinion of the medical and scientific community," says Dr. Ingbar. "More importantly, EPA is ignoring the all the kids who will be spending part of their summer in the hospital emergency room from asthma attacks caused by ozone pollution." To assist the EPA in analyzing and interpreting the scientific data, the EPA convened a panel of experts called the Clean Air Scientific Advisory Committee. CASAC, which included members with academic and industry backgrounds, analyzed the available data. They unanimously concluded the current standard does not protect public health and recommended a standard between 0.060 and 0.070 ppm/-8-hours. Since the ozone standard was last reviewed in 1997, researchers have published a growing body of evidence documenting the adverse health effects of ozone exposure, including increased respiratory disease and higher mortality rates, at levels below that being considered by the EPA in their proposed rule.

Ozone Holes

June 19, 2007

https://www.sciencedaily.com/releases/2007/06/070615084250.htm

Scientists Study Sun's Radiation To Track Pollution Sources

Colorado State University scientists are studying the reduction of solar ultraviolet radiation by atmospheric particles to learn how the various sources of pollution - biomass burning, auto exhaust and oil refining - affect the atmospheric chemistry and air quality of Mexico City. This particular technique will be used along with data retrieval from satellites around the world to study the influence of pollution on global warming and climate change.

This research allows Colorado State scientists to trace the location of where the air people breathe originally came from by studying the optical properties of aerosols along with computer forecast models. Aerosols are tiny airborne solid particles consisting of acids, water, black carbon or dust. The aerosols change the amount of solar radiation reaching the earth's surface as well as modify the heating and circulation in the atmosphere. Scientists emphasize the importance of distinguishing naturally occurring aerosols from volcanoes, dust storms, sea salt spray and forest fires as opposed to aerosols induced by human activity such as burning fossil fuels."Aerosols contribute to human health problems such as emphysema and respiratory problems," said Jim Slusser, Colorado State senior scientist and director of the UVB Monitoring and Research Program. "It is only when strict mitigation, regulatory standards and stiff fines for non-compliance were pushed through Congress that U.S. cities began to reduce harmful sulfur and black carbon aerosols. The data from our research will help decision makers in Mexico choose between various mitigation and adaptation strategies in regards to the dense pollution."Since 1992, Colorado State scientists have created research stations in 26 states to measure ultraviolet radiation and to determine its effects on agriculture and human health. The U.S. Department of Agriculture funds the $1.85 million UVB Monitoring and Research Program, or UVMRP, in Colorado State's Natural Resource Ecology Laboratory, based in the Warner College of Natural Resources. Solar measurements from the UV to the near infrared are made every three minutes at 36 climate stations established by Colorado State. This critical information - unavailable from any other source - is used by researchers at USDA, NASA, NOAA and EPA.In early March 2006, scientists from all over the world and more than 80 academic institutions and federal agencies made measurements to quantify the various chemical, radiative and dynamical factors associated with air quality in Mexico City. The project is funded by a National Science Foundation grant. As a nation, Mexico has very little regulation on emissions from oil refineries, transportation, biomass burning and power generation. As a result, Mexico City often is engulfed in ozone and aerosol pollution. At times, even surrounding rural areas are extremely hazy due to biomass burns. Ozone results when solar UV rays are absorbed by hydrocarbons and nitrogen oxides. Slusser and Andres Hernandez, a graduate student in Mexico City, collected measurements of the optical properties of aerosols from three sites within 50 kilometers of Mexico City. The unique instrumentation of the UVMRP allows separate measurement of the direct sun beam as well as scattered radiation from the rest of the sky. These capabilities allow scientists to deduce the optical properties of aerosols and in many cases identify the point sources of air pollution. "Aerosols can either cool or warm the planet depending largely on the amount and proportion of radiation that they scatter rather than absorb. With sufficient sites, we can use our instrumentation, combined with satellite retrievals, to make measurements to validate global models on mitigation strategies for reducing the greenhouse warming aerosols around the world. As in the case of ozone depletion, this effort will require participation with scientists, government and industry."Less absorbing aerosols will result in more damaging UV and greater production of tropospheric ozone. The Mexicans are in a dilemma in that even if they cleaned up the soot and black carbon from the diesel exhaust, the now scattering aerosol will result in more potential damaging UVB and ozone," Slusser said. In the next 10 years, scientists hope to apply this technique to a broad global network of major cities and provide information to policy makers and other scientists about human-induced climate change. "The aerosol work that we performed in Mexico City is relevant to climate modelers who need to understand the influence of mega cities in developing countries such as Mexico on climate change. Climate modelers will need our UVB and visible solar radiation data to validate their computer models. Most models predict greater and greater extremes in weather - precipitation, wind, storms and temperature."The UVMRP produces the world's most extensive time series of solar radiation. This record becomes ever more useful as it is extended. Eventually we will be able to separate cyclical influences such as El Nino and the solar cycle from trends and year-to-year variability," Slusser said. In November 2006, Slusser and Barry Lefer from the University of Houston were awarded a grant from the EPA to study Houston's pollution using the pollution aerosols technique.UVB is a narrow range of the sun's energy that is only partially absorbed by the ozone layer and can damage biological organisms. Ultraviolet light is a more energetic portion of the spectrum than light that is visible to the naked eye. It is separated into three groups: UVA, which is not damaging to organisms; UVB, which is known to damage DNA and result in mutations; and UVC. Unlike UVB, harmful UVC rays are absorbed entirely by the ozone.

Ozone Holes

May 19, 2007

https://www.sciencedaily.com/releases/2007/05/070517142558.htm

Southern Ocean Carbon Sink Weakened

Scientists have observed the first evidence that the Southern Ocean’s ability to absorb the major greenhouse gas, carbon dioxide, has weakened by about 15 per cent per decade since 1981.

In research published in Science, an international research team – including CSIRO’s Dr Ray Langenfelds – concludes that the Southern Ocean carbon dioxide sink has weakened over the past 25 years and will be less efficient in the future. Such weakening of one of the Earth’s major carbon dioxide sinks will lead to higher levels of atmospheric carbon dioxide in the long-term.Dr Paul Fraser, who leads research into atmospheric greenhouse gases at CSIRO Marine and Atmospheric Research, says the international team’s four-year study concludes that the weakening is due to human activities.“The researchers found that the Southern Ocean is becoming less efficient at absorbing carbon dioxide due to an increase in wind strength over the Ocean, resulting from human-induced climate change,” Dr Fraser says.“The increase in wind strength is due to a combination of higher levels of greenhouse gases in the atmosphere and long-term ozone depletion in the stratosphere, which previous CSIRO research has shown intensifies storms over the Southern Ocean.”The increased winds influence the processes of mixing and upwelling in the ocean, which in turn cause an increased release of carbon dioxide into the atmosphere, reducing the net absorption of carbon dioxide into the ocean.“Combined, the Earth’s land and ocean sinks absorb about half of all carbon dioxide emissions from human activities,” Dr Fraser says. “The Southern Ocean takes up 15 per cent of these emissions, hence a reduction in its efficiency will have serious implications for atmospheric carbon dioxide concentrations over coming decades.”Dr Fraser points to one piece of good news: that ozone levels in the stratosphere have stopped declining and should recover slowly in coming decades. “Thus the impact of ozone depletion on the Southern Ocean carbon dioxide sink will lessen in the future, but the impact of increasing levels of greenhouse gases will continue unabated.”The international team comprised researchers from CSIRO in Australia, the Max-Planck Institute in Germany, the University of East Anglia and British Antarctic Survey in England, the Climate Monitoring and Diagnostics Laboratory in the US, NIWA in New Zealand, the South African Weather Service, LSCE/IPSL and CNRS in France, and the Centre for Atmospheric and Oceanic Studies in Japan.The team used observations from 40 stations around the world, including Cape Grim in north-west Tasmania. The Cape Grim station, operated by the Australian Bureau of Meteorology, monitors and studies changes in global atmospheric composition in a program led by CSIRO and the Bureau.Meanwhile, research to increase understanding and improve management of the oceans will increase following the announcement today by WA Premier, the Hon Alan Carpenter. The Western Australian Marine Science Institution (WAMSI) is a new $A21 million, five-year research collaboration focussing on the marine environment to Australia’s west.

Ozone Holes

May 15, 2007

https://www.sciencedaily.com/releases/2007/05/070514145322.htm

Summer Temperatures And Ozone Levels Expected To Increase, With Significant Health Effects

In a first of its kind study, a research team based at Columbia's Mailman School of Public Health found that changes in urban sprawl and climate that are projected to occur in the New York City metropolitan area by the 2050s could significantly affect air quality and health in the region. Findings suggest that urban sprawl alone could result in a 1°F rise in average summer temperatures and a 16 percent increase in unhealthy levels of ozone during episodes.

This is the first successful attempt to simulate both weather and air quality due to climate and land use changes at a scale that is relevant to local and regional policy makers. Using a unique modeling system, the researchers were able to link climate change, land use change, and air quality, to predict sprawling development over this region in the year 2050 compared to present-day conditions. This new system makes it possible for the first time to examine the separate and joint influences of land use, climate and emissions changes on future environmental conditions -- and resulting health implications such as asthma attacks and difficulty in breathing, ER visits and hospitalizations, and even increased risk of death for vulnerable persons. With a population exceeding 21 million people in the greater NYC metropolitan area, ongoing urbanization puts a significant strain on natural resources and impacts air pollution levels and regional climate. The study highlights the value of modeling systems that quantitatively assess the potential impacts of changes in climate, emissions and land use on environmental health in the region. "As more land in this region is expected to be converted to human-dominated uses over the coming decades, it is of critical importance to evaluate the potential effects on public health and welfare," says Patrick Kinney,ScD, associate professor of Environmental Health Sciences at the Mailman School of Public Health and principal investigator of this project. "Furthermore, utilizing the system described here for sensitivity simulations even for relatively small areas may be of interest to planning organizations that focus on the state, county, or municipal level."While this study was focused mainly on land-use change, earlier research by the team examined the potential impacts of climate change on air quality and heat across the metropolitan area, as well as potential effects on summertime ozone-related deaths. For example, ozone-related deaths in a typical summer could increase by 55 deaths across the 31 counties of the New York City Metro area due to climate change alone. County-specific increases ranged from zero to six deaths/summer, with the largest increases occurring in the New York City. In a related study also just released, Dr. Kinney collaborated with other scientists, including Michelle Bell of Yale University, to extend his results to 50 large cities in the eastern U.S. They found that changes in ozone levels could detrimentally affect air quality and thereby harm human health through increases in total, cardiovascular, and respiratory mortality; hospital admissions for asthma; and hospital admissions for respiratory causes for older populations. The largest increases in ozone levels were predicted to occur in cities that already have high pollution levels, meaning that these locations may need to increase their emission control efforts to counteract any adverse impact of climate change on ozone concentrations. "These adverse health impacts highlight the need for diligence over policies that control greenhouse gas emissions and that improve regional air quality," said Dr. Kinney. "In addition to their effects on long-term climate change and health, such policies can lead to even short-term local benefits to air quality and thereby, human health."

Ozone Holes

May 1, 2007

https://www.sciencedaily.com/releases/2007/05/070501081737.htm

Los Angeles Most Polluted US City, According To American Lung Association Report

For the first time since the American Lung Association began issuing its annual air quality report card, data reveal a split picture along either side of the Mississippi River, as particle pollution (soot)—the most dangerous pollutant—increased in the East but decreased in the West, while ozone (smog) decreased nationwide from peaks reported in 2002. The number of counties scoring an A grade for ozone levels increased from 82 in 2000 to 145 this year, but particle pollution levels show an ominous trend, with F grades nearly doubling in just one year, according to American Lung Association State of the Air: 2007. 

“The increased particle pollution in the East is a particularly troubling trend, because exposure to particle pollution can not only take years off your life, it can  threaten your life immediately,” said Terri E. Weaver, PhD, RN, American Lung Association Chair. “Even in many areas EPA currently considers safe, the science clearly shows that the air is too often dangerous to breathe, particularly for those with lung disease.  Protecting Americans from potentially deadly air pollution means we need more protective federal standards, so that every community in the United States can have truly clean air.”Higher soot levels in the East are linked to an increase in electricity generated by heavy polluting power plants. In the West, by contrast, soot levels continue to drop even in areas that rank historically high in particle pollution. California showed the most improvement with 32 counties dropping their year-round particle pollution levels.Ozone pollution dropped thanks to a late 1990s requirement to clean up emissions of the raw ingredients of smog, as well as cooler summers in 2003 and 2004. Reductions in the nitrogen oxide emissions from coal-fired power plants that were in place by 2004 kept smog levels down, even when the heat returned in summer 2005 in much of the East. In the West, particularly in California, aggressive measures to reduce emissions from a wide range of air pollution sources (cars, trucks, and other mobile sources) contributed to fewer high ozone days.“The good news is that there’s less ozone everywhere. Yet, we remain concerned because the science shows that millions are still at risk from ozone that exceeds acceptable levels,” Dr. Weaver said. “Breathing ozone smog threatens serious health risks, including new evidence that links it to premature death.” she said. “We’re calling on EPA to set new standards for ozone at levels that would protect public health as the Clean Air Act requires.”The American Lung Association State of the Air: 2007 ranks cities and counties most polluted by ozone, 24-hour particle pollution, and annual particle pollution, and reports county-by-county populations at risk from unhealthful levels of the most dangerous forms of air pollution. Particle pollution is reported for both short-term (24-hour) periods and annual averages.According to the report, 46 percent (136 million people) of the U.S. population lives in 251 counties where they are exposed to unhealthful levels of air pollution in the form of either ozone or short-term or year-round levels of particles. About 38.3 million Americans – nearly one in 8 people – live in 32 counties with unhealthful levels of all three: ozone and short-term and year-round particle pollution. One-third of the U.S. population lives in areas with unhealthful levels of ozone, a significant reduction since the last report when nearly half did, yet 99 million Americans still live in counties with F grades for ozone.Roughly one in three (more than 93.7 million) people in the United States lives in an area with unhealthful short-term levels of particle pollution, a significant increase since the last report, which  is only partially due to the new, slightly lower threshold of unhealthful air recognized in this report (based on the newly adopted national standards). Nearly one in five (more than 54 million) people in the United States lives in an area with unhealthful year-round levels of particle pollution.Los Angeles ranked as the most polluted city in the nation for all categories in the report, even though LA’s pollution levels have dropped.  Other cities ranking among the worst for ozone include several in southern California, as well as large cities in Texas and on the east coast, including Houston, Dallas, New York, Washington, DC, and Philadelphia. Other cities on the lists of the worst for particle pollution include many in the Midwest and Mid-Atlantic states, including Pittsburgh, Detroit, Chicago, Cleveland, Washington, DC-Baltimore, Philadelphia, and New York. With ozone pollution dropping in the eastern US, several cities returned to the list of most polluted cities despite improved ozone levels, including Atlanta, Phoenix, and Baton Rouge. They reappeared because of greater improvements by other cities.  Some cities moved up to the worst cities for ozone list for the first time, including Las Vegas, Milwaukee and Kansas City.“The American Lung Association is fighting for tougher federal standards because they protect Americans from dangerous levels of air pollution,” Dr. Weaver said. “Air pollution shortens lifespan, it lands our children and elderly in emergency rooms, and it can make children and teens more vulnerable to lung disease for the rest of their lives.”To see how your community ranks in the American Lung Association State of the Air: 2007 report and learn how you can protect yourself and your family from air pollution, go to

Ozone Holes

April 18, 2007

https://www.sciencedaily.com/releases/2007/04/070418072616.htm

Ethanol Vehicles Pose Significant Risk To Health, New Study Finds

Ethanol is widely touted as an eco-friendly, clean-burning fuel. But if every vehicle in the United States ran on fuel made primarily from ethanol instead of pure gasoline, the number of respiratory-related deaths and hospitalizations likely would increase, according to a new study by Stanford University atmospheric scientist Mark Z. Jacobson. His findings are published in the April 18 online edition of the journal Environmental Science & Technology (ES&T).

"Ethanol is being promoted as a clean and renewable fuel that will reduce global warming and air pollution," said Jacobson, associate professor of civil and environmental engineering. "But our results show that a high blend of ethanol poses an equal or greater risk to public health than gasoline, which already causes significant health damage." For the study, Jacobson used a sophisticated computer model to simulate air quality in the year 2020, when ethanol-fueled vehicles are expected to be widely available in the United States. "The chemicals that come out of a tailpipe are affected by a variety of factors, including chemical reactions, temperatures, sunlight, clouds, wind and precipitation," he explained. "In addition, overall health effects depend on exposure to these airborne chemicals, which varies from region to region. Ours is the first ethanol study that takes into account population distribution and the complex environmental interactions." In the experiment, Jacobson ran a series of computer tests simulating atmospheric conditions throughout the United States in 2020, with a special focus on Los Angeles. "Since Los Angeles has historically been the most polluted airshed in the U.S., the testbed for nearly all U.S. air pollution regulation and home to about 6 percent of the U.S. population, it is also ideal for a more detailed study," he wrote. Jacobson programmed the computer to run air quality simulations comparing two future scenarios: A vehicle fleet (that is, all cars, trucks, motorcycles, etc., in the United States) fueled by gasoline, versus A fleet powered by E85, a popular blend of 85 percent ethanol and 15 percent gasoline. The results of the computer simulations were striking. "We found that E85 vehicles reduce atmospheric levels of two carcinogens, benzene and butadiene, but increase two others—formaldehyde and acetaldehyde," Jacobson said. "As a result, cancer rates for E85 are likely to be similar to those for gasoline. However, in some parts of the country, E85 significantly increased ozone, a prime ingredient of smog." Inhaling ozone—even at low levels—can decrease lung capacity, inflame lung tissue, worsen asthma and impair the body's immune system, according to the Environmental Protection Agency. The World Health Organization estimates that 800,000 people die each year from ozone and other chemicals in smog. "In our study, E85 increased ozone-related mortalities in the United States by about 200 deaths per year compared to gasoline, with about 120 of those deaths occurring in Los Angeles," Jacobson said. "These mortality rates represent an increase of about 4 percent in the U.S. and 9 percent in Los Angeles above the projected ozone-related death rates for gasoline-fueled vehicles in 2020." The study showed that ozone increases in Los Angeles and the northeastern United States will be partially offset by decreases in the southeast. "However, we found that nationwide, E85 is likely to increase the annual number of asthma-related emergency room visits by 770 and the number of respiratory-related hospitalizations by 990," Jacobson said. "Los Angeles can expect 650 more hospitalizations in 2020, along with 1,200 additional asthma-related emergency visits." The deleterious health effects of E85 will be the same, whether the ethanol is made from corn, switchgrass or other plant products, Jacobson noted. "Today, there is a lot of investment in ethanol," he said. "But we found that using E85 will cause at least as much health damage as gasoline, which already causes about 10,000 U.S. premature deaths annually from ozone and particulate matter. The question is, if we're not getting any health benefits, then why continue to promote ethanol and other biofuels? "There are alternatives, such as battery-electric, plug-in-hybrid and hydrogen-fuel cell vehicles, whose energy can be derived from wind or solar power," he added. "These vehicles produce virtually no toxic emissions or greenhouse gases and cause very little disruption to the land—unlike ethanol made from corn or switchgrass, which will require millions of acres of farmland to mass-produce. It would seem prudent, therefore, to address climate, health and energy with technologies that have known benefits." This ES&T study was partially supported by NASA.

Ozone Holes

April 16, 2007

https://www.sciencedaily.com/releases/2007/04/070415122833.htm

NOAA, NASA To Restore A Key Climate Sensor

NOAA and NASA announced a plan to restore a key climate sensor, designed to give climate researchers a more precise depiction of the structure of the Earth's ozone layer, to the National Polar-orbiting Operational Environmental Satellite System Preparatory Project. The sensor, called the Ozone Mapping and Profiler Suite Limb, will be returned to the NPP satellite, set to launch in 2009.

The NPOESS Integrated Program Office will give Northrop Grumman Space Technology, the NPOESS prime contractor, conditional authority to proceed with the effort, with final approval contingent upon successful negotiations between the contractor and the IPO of the full cost proposal."Having the OMPS Limb will give scientists a more complete picture of the content and distribution of gases in the atmosphere," said retired Navy Vice Admiral Conrad C. Lautenbacher, Ph.D, undersecretary of commerce for oceans and atmosphere and NOAA administrator. "NOAA is committed to working with the scientific community to address their climate and other satellite observation requirements. This is a great step in that direction."NPOESS is a tri-agency environmental monitoring program directed by the Department of Commerce (NOAA's parent agency), the Department of Defense and NASA. With the launch of the first spacecraft planned for 2013, NPOESS will bring improved data and imagery that will allow better weather forecasts, severe-weather monitoring and detection of climate change. A recent restructuring of the NPOESS program had removed the OMPS Limb sensor from NPP.The NPP mission will provide continuity of observations that were begun by NASA's Earth Observing System satellites Aqua and Terra. NPP also will provide risk reduction for three of the NPOESS critical sensors, as well as the data processing and ground systems. NOAA and NASA have agreed to split equally the cost to restore the OMPS Limb onto the NPP spacecraft. The OMPS Limb, which measures the vertical distribution of ozone, complements existing NPOESS systems and will give scientists a better understanding of the structure of the atmosphere. Restoring the OMPS Limb sensor directly addresses one of the recommendations of the recently released National Research Council's "Earth Science Applications from Space: National Imperative for the Next Decade and Beyond.""This sensor will allow us to move forward with the next generation of technology for weather and climate prediction," said NASA Administrator Michael Griffin.

Ozone Holes

March 30, 2007

https://www.sciencedaily.com/releases/2007/03/070329075220.htm

New Asthma Inhaler Propellant Effective, But Costlier

A common asthma inhaler powered by a new propellant is safe and effective but could come at nearly triple the cost to consumers until a generic version hits the market, according to a review in the New England Journal of Medicine.

Conducted by two university professors and a director for the Food and Drug Administration, the review examines the consequences of switching to hydrofluoroalkane, which is replacing chlorofluorocarbon, or CFC, as a key ingredient in albuterol inhalers designed to relieve asthma. The FDA has ruled that U.S. sales of CFC albuterol inhalers be prohibited after 2008.About 52 million prescriptions are filled for albuterol each year in the United States, with most containing a generic version of CFC. But because of rising global concerns about CFC's ozone-depleting effects, "medically essential" inhalers are finally joining a list of banned products that started in 1978.The researchers say their analyses show that inhalers with CFC and the new brands that contain hydrofluoroalkane, or HFA, are equally effective at treating asthma. "Hopefully, by communicating with health-care professionals, we'll be able to reassure patients," said Leslie Hendeles, the University of Florida professor of pharmacy and pediatrics who spearheaded the review. He worked with Dr. Gene L. Colice, a professor of medicine at The George Washington University School of Medicine, and Dr. Robert J. Meyer, who directs the Office of Drug Evaluation II at the FDA.Albuterol, one of the medicines that relieves asthma attacks, is the seventh most commonly prescribed drug in the United States. Because it's so widely used, the report predicts Americans will spend an additional $1.2 billion a year on three patented inhaler brands containing the new propellant (Ventolin, ProAir and Proventil) until generic versions reach pharmacies, probably after 2012. Patients who pay for their own medications will probably be hit hardest by new costs -- paying on average $26 more per prescription, or $312 more per year -- but people with prescription benefit plans will likely face higher co-pays as well, according to the review.Additionally, while the new inhalers are just as effective as their traditional CFC counterparts, a few differences have been reported. One brand, for example, comes sealed in a protective pouch. After that pouch is opened, the drug carries a shelf life of just two months, while most inhalers can typically be stored for 15 to 24 months, Hendeles said.Consumers will also notice that only the Ventolin brand of HFA inhaler comes with a counter to track how much medicine is left. For that reason, Hendeles suggests keeping a backup inhaler handy if physicians prescribe a device without a counter."There isn't any reliable way of estimating when they're going to run out," said Hendeles, who also serves as a consultant to the FDA.The review also reports that some HFA inhalers tend to clog more easily. To prevent clogging in HFA inhalers, Hendeles advised, patients should remove the devices' metal canister once a week and clean the plastic actuators with warm water.Not all of the new HFA inhaler products are ideal for everyone and health-care providers and their patients should be aware of important differences. Two brands of HFA inhalers contain ethanol. It may not be an appropriate therapy choice depending on the patient's religious beliefs, and can temporarily cause a false reading on breath alcohol tests performed by law enforcement agencies, Hendeles said.Hendeles noted that CFC inhalers release negligible amounts of the propellant, and do not pose a threat to ozone depletion. However, the United States joined more than 185 other countries in signing the Montreal Protocol, an international treaty requiring complete withdrawal of all CFC products. The inhaler, deemed medically necessary, was exempt until new market replacements using HFA became available.Hendeles said he hopes the review will dispel myths about HFA for doctors and patients. Still, even though HFA inhalers are safe for the environment and effective at treating asthma, some people may feel uncomfortable when making the switch. HFA inhalers spew slower and warmer plumes of medicine than their CFC counterparts, so asthma patients may fear their new inhalers aren't strong enough."There undoubtedly will be some people who are absolutely certain it doesn't work as well," Hendeles said, adding that patient education is the key to proper care.Dr. Rachel L. Miller, an assistant professor of clinical medicine and public health at Columbia University, said she would urge asthma patients to consult their pharmacist or health-care provider if they're nervous about using the new inhalers."It's really the same drug," said Miller, who has worked with both CFC and HFA inhalers. "I have found both of them, in my personal experience, seem to work fine."

Ozone Holes

March 29, 2007

https://www.sciencedaily.com/releases/2007/03/070322105700.htm

Solar Blast From The Past Dwarfed Modern Ozone Destruction

A burst of protons from the Sun in 1859 destroyed several times more ozone in Earth's atmosphere than did a 1989 solar flare that was the strongest ever monitored by satellite, a new analysis finds.

When energetic protons from the Sun penetrate Earth's stratosphere, they ionize and dissociate nitrogen and oxygen molecules, which then form ozone-depleting nitrogen oxides.Thomas et al. developed a scale factor between known nitrate enhancements from recent solar proton events. By using data on nitrate enhancements in Greenland ice cores following the September 1859 burst, they used the scale factor to determine that the total energy released by that solar proton event was 6.5 times larger than the amount released in the 1989 event. Models using this energy total showed that 3.5 times more ozone was destroyed in the 1859 episode than in that of 1989.Because ozone regulates the amount of harmful ultraviolet radiation reaching Earth, the authors emphasized that understanding intense solar proton events will be important to predicting potential damage to the biosphere.Title: Modeling atmospheric effects of the September 1859 solar flareAuthors: B. C. Thomas: Department of Physics and Astronomy, Washburn University, Topeka, Kansas, U.S.A.; C. H. Jackman: Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, Maryland, U.S.A.; A. L. Melott: Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas, U.S.A.Source: Geophysical Research Letters (GRL) paper 10.1029/2006GL029174, 2007

Ozone Holes

March 24, 2007

https://www.sciencedaily.com/releases/2007/03/070323134845.htm

Is Solar UV Frying Fish?

Marine and freshwater organisms could be facing damage due to increasing levels of ultraviolet (UV) radiation, according to a United Nations (UN) commissioned review.

Aquatic ecosystems produce over half the biomass of the Earth and are an integral part of the planet’s biosphere. The international team behind the review is worried that the depleted ozone layer has exposed these ecosystems to harmful levels of UV radiation, particularly in polar regions where the ozone layer is the thinnest.There could also be wider implications for climate change, since if UV damage cuts marine ecosystem productivity, the oceans’ capacity to mop up the greenhouse gas carbon dioxide would fall. This extra atmospheric CO2 could then add to global warming.Additionally, the annual phytoplankton boom, which supports the entire Antarctic aquatic food chain, is currently protected from UV damage by a layer of sea-ice.Warmer climates would mean sea-ice melts earlier, increasing UV exposure. These plankton are particularly vulnerable to UV damage as the low temperatures slow their repair mechanisms.A team of scientists from Germany, India and America compiled the review. It comprised hundreds of separate studies into to the effects of UV radiation, covering organisms from plankton to frogs and fish.The findings highlight that while the effects of UV radiation on entire ecosystems are difficult to measure and model, the impact on individual species can be dramatic.Numbers of frogs, toads and other amphibians have fallen across the world over the last 10 years. And while the exact cause is a complex combination of factors, the review highlights more than 50 research papers implicating UV radiation. The study is part of a wider United Nations Environmental Programme (UNEP) report on interactions between ozone depletion and climate change.Every few years, UNEP produces a report for parties to the Montreal Protocol – the 1987 international agreement to phase out production of most ozone depleting compounds, such as CFCs, by 2000. The report is subsequently published in Photochemical & Photobiological Sciences, to make it available to the entire scientific community.Janet Bornman, co-chair of the Environmental Effects Assessment Panel of the UNEP and co-ordinator of the report, said: “It is hoped that the publication will stimulate the scientific community to continue working on the gaps in knowledge that still exist.“We hope that it will help keep scientists aware of their involvement in the protection of the environment for all forms of life on Earth”. The news is reported in the latest edition of the Royal Society of Chemistry journal Photochemical & Photobiological Sciences.

Ozone Holes

March 15, 2007

https://www.sciencedaily.com/releases/2007/03/070314110559.htm

First Ozone And Nitrogen Dioxide Measurements From The Global Ozone Monitoring Experiment

The Global Ozone Monitoring Experiment-2 (GOME-2) on board MetOp-A launched in October 2006 and currently undergoing commissioning has delivered the first geophysical products for monitoring the Earth's ozone layer, and European and global air quality.

This marks the start of a long-term European commitment to monitor the recovery of the ozone layer and to support the monitoring and forecasting of air quality, both for European citizens and at a global level. The products have been developed by the German Aerospace Center (DLR) in partnership with EUMETSAT’s Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M SAF), which is coordinated by the Finnish Meteorological Institute (FMI). The O3M SAF generates, validates, archives and distributes atmospheric ozone, trace gases, aerosols and surface-ultraviolet radiation data products using measurements from MetOp-A.  GOME-2, a scanning spectrometer, follows on from successful GOME flown on ESA’s ERS-2 satellite launched in April 1995, and provides near-global coverage on a daily basis. The instrument measures profiles of atmospheric ozone and the distribution of other trace gases in the atmosphere. The instrument measures profiles of atmospheric ozone and the distribution of other trace gases in the atmosphere that are related to the depletion of ozone in the stratosphere, and to natural and anthropogenic sources of pollution. The amount of surface ultraviolet radiation is also derived from GOME-2 measurements. The ozone layer at an altitude of 20-30 kilometres shields the Earth from harmful ultra-violet radiation. However, the depletion of this protective ozone layer, which is most noticeable over the Arctic and Antarctic regions, is of particular environmental concern. The resulting increased levels of ultraviolet radiation reaching the surface of the Earth can cause serious damage to human health, agriculture, forests and water ecosystems. High levels of atmospheric pollutants such as nitrogen dioxide produced by fossil fuel combustion, can damage respiratory health and contribute to acid deposition which harms soil and vegetation.

Ozone Holes

March 12, 2007

https://www.sciencedaily.com/releases/2007/03/070309092330.htm

Airborne Pollutants Know No Borders

Mounting evidence suggests that gas and aerosol pollutants are routinely transported by winds across and between continents and can affect the air and climate of areas far from their source.

Scientists studying atmospheric changes have observed smoke plumes from wildfires in the boreal forests of Alaska and Canada that were carried as far as parts of Europe, Africa and the Arctic. Satellite imagery was used to guide field research that used weather instruments aboard five different aircraft and the ship Ronald H. Brown to sample the air above North America and the Atlantic Ocean. "Our findings are the most extensive characterization of the North American troposphere to date," said Hanwant Singh, project scientist at NASA Ames Research Center, in California's Silicon Valley. “We investigated the transport and transformation of gases and aerosols on intercontinental scales. Pollution plumes from Asia and North America were intercepted and analyzed as they were transported over the North American continent and the Atlantic.” Singh led the Intercontinental Chemical Transport Experiment – North America (INTEX-A) campaign that studied the chemical composition and processes of atmospheric changes over North America.Changes in atmospheric composition and climate have been attributed to rapid industrialization and the related energy consumption. Fossil fuels are the main source of energy. Studies have shown that air pollutants from carbon-based fuels include such contaminants as carbon monoxide, nitrogen oxides and other harmful gases and particles.Any substance introduced into the atmosphere has the potential to circle the Earth. In the last decade, field experiments have documented the flow of air pollutants from the Asian continent to the Pacific Ocean. Typically, the transport of Asian pollution to North America peaks in spring. However, five major Asian plumes were observed at lower atmospheric levels crossing North America in the summer. When plumes were sampled and analyzed, findings showed fewer human-produced pollutants (such as carbon dioxide) and more biogenic trace gases, which occur naturally from microbial activity in soil (such as nitrous oxide and nitric oxide) and wetlands, swamps and rice paddies (such as methane.) “We found that air quality across the North American continent was greatly polluted by major fires over Alaska and Canada and strong winds from Asia,” explained Singh.While scientists witnessed air pollutants flow into North America from Asia, they also observed air pollution flow from North America. Summertime was selected to do field research because of greater sunlight, plant emissions, and the possibility wildfires all contributing to increased smog. To sample air coming across the Atlantic, four aircraft, each carrying different weather instruments, were strategically based in New Hampshire (USA), Faial (Azores) and Creil (France). Smoke plumes from these wildfires were detected by several satellites and affected areas thousands of miles away. Smoke reached Europe without significant removal of particles. Receptor sites along the pathway showed an increase in ozone and decrease in carbon monoxide in the upper troposphere over the Atlantic. Data also showed relatively little direct Asian influence on ozone over the United States, but a sizable U.S. influence on Europe’s ozone.Ozone can be both beneficial and harmful to life on Earth. In the stratosphere, it prevents most of the harmful ultraviolet rays from reaching the Earth’s surface. But in the troposphere, near the Earth’s surface, the ozone is a pollutant. Surface ozone forms when nitrogen oxides and volatile organic compounds react in the presence of sunlight.Just as Asia’s pollution influences the air quality over North America, and North America’s pollution affects European air, studies also show that ozone and other oxidants travel to Asia from Europe.These and related studies appeared in the American Geophysical Union issues of the Journal of the Geophysical Research, 2006.For further information, please visit:

Ozone Holes

March 3, 2007

https://www.sciencedaily.com/releases/2007/03/070302130935.htm

Computer-designed Molecule To Clean Up Fluorocarbons?

The chemical bond between carbon and fluorine is one of the strongest in nature, and has been both a blessing and a curse in the complex history of fluorocarbons. Now, in a powerful demonstration of the relatively new field of "computational chemistry," researchers at the National Institute of Standards and Technology (NIST) and the Interdisciplinary Network of Emerging Science and Technology group (INEST, sponsored by Philip Morris USA) have designed--in a computer--a wholly theoretical molecule to pull the fluorine out of fluorocarbons.*

At sea level, the strong C-F bond makes fluorocarbons thermally and chemically stable. As a result, fluorocarbons have been used in many commercial applications including refrigerants, pesticides and non-stick coatings. In the upper atmosphere, however, high-energy photons and highly reactive ozone molecules can break apart fluorocarbons, with the well-known consequence of a depleted ozone layer and increased ultraviolet radiation at ground level. A determined chemist can break down fluorocarbons at ground level with certain organometallic compounds, but the reactions take a long time at very high temperatures. Other known reagents are both highly toxic and inefficient, so chemists have been searching for an economical and environmentally friendly method to dispose of fluorocarbons.Reasoning that the problem already may have been solved by nature, the NIST/Philip Morris team looked to an enzyme called fluoroacetate dehalogenase used by a South African bacterium, Burkholderia sp. The enzyme enables the bacterium to pull the fluoride ion out of sodium fluoroacetate (disrupting a poisonous compound) at room temperature and without problematic metal ions. Enzymes are giant molecules, evolved to survive and work in the complex environment of a living organism; they can be difficult and expensive to adapt to an industrial process. Instead, the research team applied basic quantum mechanical theory of electron structures in molecules, together with the example of a known molecule that binds to and extracts chlorine ions, to calculate the make-up and geometry of the critical "active site" in the enzyme that does the work. They then designed in software a large ring-shaped molecule to hold those components in just the right orientation to break the C-F bond in methyl fluoride, a simple fluorocarbon.Researchers at the University of Texas now are synthesizing the new molecule to test its effectiveness. If it matches theoretical predictions, it will be the first example of a simple organic molecular system able to break C-F bonds without extreme temperature and pressure conditions, and a demonstration of a novel technique for designing man-made molecules that can mimic the extraordinary selectivity and chemical activity of natural enzymes. Notes lead researcher Carlos Gonzalez, "All of these useful things are in nature, you just have to find them and make them more efficient."* F. Hæffner, M. Marquez and C. Gonzalez. Theoretical evidence for C-F bond activation by a fluoro-calix[4]pyrrole-tert-amine macrocycle. J. Phys. Chem. A 2007, 111, 268-272.

Ozone Holes

February 24, 2007

https://www.sciencedaily.com/releases/2007/02/070222102714.htm

In Presence Of Fragrant Cleaning Products, Air Purifiers That Emit Ozone Can Dirty The Air

Indoor air purifiers that produce even small quantities of ozone may actually make the air dirtier when used at the same time as household cleaning products, scientists at UC Irvine have discovered.

Ozone emitted by purifiers reacts in the air with unsaturated volatile organic compounds such as limonene – a chemical added to cleaning supplies that gives them a lemon fragrance – to create additional microscopic particles, scientists found. Certain ionic purifiers emit ozone as a byproduct of ionization used for charging airborne particles and electrostatically attracting them to metal electrodes. Ozonolysis purifiers emit ozone at higher levels on purpose with the ostensible goal of oxidizing volatile organic compounds in the air.This research appeared online this morning in Environmental Science and Technology.“The public needs to be aware that every air purification approach has its limitation, and ionization air purifiers are no exception,” said Sergey Nizkorodov, assistant professor of chemistry at UCI and co-author of the study. “These air purifiers can not only elevate the level of ozone, a formidable air pollutant in itself, but also increase the amount of harmful particulate matter in indoor air.”High levels of airborne particles can aggravate asthma and cardiovascular problems, and have been linked to higher death and lung cancer rates. Excess ozone can damage the lungs, causing chest pain, coughing, shortness of breath and throat irritation.Nizkorodov and students Ahmad Alshawa and Ashley Russell conducted their experiment in a sparsely furnished office with a floor area of about 11 square meters. They placed an ozone-emitting air purifier in the middle of the room along with a large fan to better mix the air. At timed intervals, limonene vapor was injected in the room. Samples of the air were taken about one meter from the purifier and analyzed for ozone and particulate matter levels.The researchers tested two types of air purifiers – a commercial ionic purifier that emits about 2 milligrams of ozone per hour, and an ozonolysis purifier that emits approximately 100 milligrams of ozone per hour.Continuous operation of the ionic purifier without limonene resulted in a slight reduction in the average particle concentration, while operation of the ozonolysis purifier resulted in no detectable effect on the particle level. When limonene was added to the room, the particle concentration shot up in both cases, on some occasions up to 100 times the original level. Adding limonene to the room when a purifier was not operating produced little change in the overall particle level.The scientists also developed a mathematical model that precisely matched their experimental observations. This model can be used to predict whether a given air purifier will make the air dirtier in a given indoor environment.Scientific data on indoor air purifiers will be important as officials begin the process of regulating air purifiers that emit ozone. In September 2006, California Gov. Arnold Schwarzenegger signed into law Assembly Bill 2276, requiring the California Air Resources Board to develop regulations that will set emission standards and procedures for certifying and labeling the devices.“State regulators should set a strict limit on the amount of ozone produced by air purifiers to protect the public from exposure to unhealthy ozone and particulate matter levels,” Nizkorodov said.The National Science Foundation funded this study.

Ozone Holes

February 17, 2007

https://www.sciencedaily.com/releases/2007/02/070215144314.htm

Antarctic Temperatures Disagree With Climate Model Predictions

A new report on climate over the world's southernmost continent shows that temperatures during the late 20th century did not climb as had been predicted by many global climate models.

This comes soon after the latest report by the Intergovernmental Panel on Climate Change that strongly supports the conclusion that the Earth's climate as a whole is warming, largely due to human activity. It also follows a similar finding from last summer by the same research group that showed no increase in precipitation over Antarctica in the last 50 years. Most models predict that both precipitation and temperature will increase over Antarctica with a warming of the planet. David Bromwich, professor of professor of atmospheric sciences in the Department of Geography, and researcher with the Byrd Polar Research Center at Ohio State University, reported on this work at the annual meeting of the American Association for the Advancement of Science at San Francisco. "It's hard to see a global warming signal from the mainland of Antarctica right now," he said. "Part of the reason is that there is a lot of variability there. It's very hard in these polar latitudes to demonstrate a global warming signal. This is in marked contrast to the northern tip of the Antarctic Peninsula that is one of the most rapidly warming parts of the Earth." Bromwich says that the problem rises from several complications. The continent is vast, as large as the United States and Mexico combined. Only a small amount of detailed data is available -- there are perhaps only 100 weather stations on that continent compared to the thousands spread across the U.S. and Europe . And the records that we have only date back a half-century. "The best we can say right now is that the climate models are somewhat inconsistent with the evidence that we have for the last 50 years from continental Antarctica . "We're looking for a small signal that represents the impact of human activity and it is hard to find it at the moment," he said. Last year, Bromwich's research group reported in the journal Science that Antarctic snowfall hadn't increased in the last 50 years. "What we see now is that the temperature regime is broadly similar to what we saw before with snowfall. In the last decade or so, both have gone down," he said. In addition to the new temperature records and earlier precipitation records, Bromwich's team also looked at the behavior of the circumpolar westerlies, the broad system of winds that surround the Antarctic continent. "The westerlies have intensified over the last four decades of so, increasing in strength by as much as perhaps 10 to 20 percent," he said. "This is a huge amount of ocean north of Antarctica and we're only now understanding just how important the winds are for things like mixing in the Southern Ocean." The ocean mixing both dissipates heat and absorbs carbon dioxide, one of the key greenhouse gases linked to global warming. Some researchers are suggesting that the strengthening of the westerlies may be playing a role in the collapse of ice shelves along the Antarctic Peninsula. "The peninsula is the most northern point of Antarctica and it sticks out into the westerlies," Bromwich says. "If there is an increase in the westerly winds, it will have a warming impact on that part of the continent, thus helping to break up the ice shelves, he said. "Farther south, the impact would be modest, or even non-existent." Bromwich said that the increase in the ozone hole above the central Antarctic continent may also be affecting temperatures on the mainland. "If you have less ozone, there's less absorption of the ultraviolet light and the stratosphere doesn't warm as much." That would mean that winter-like conditions would remain later in the spring than normal, lowering temperatures. "In some sense, we might have competing effects going on in Antarctica where there is low-level CO2 warming but that may be swamped by the effects of ozone depletion," he said. "The year 2006 was the all-time maximum for ozone depletion over the Antarctic." Bromwich said the disagreement between climate model predictions and the snowfall and temperature records doesn't necessarily mean that the models are wrong. "It isn't surprising that these models are not doing as well in these remote parts of the world. These are global models and shouldn't be expected to be equally exact for all locations," he said.

Ozone Holes

February 3, 2007

https://www.sciencedaily.com/releases/2007/02/070201144849.htm

Cloning The Smell Of The Seaside

Scientists from the University of East Anglia have discovered exactly what makes the seaside smell like the seaside -- and bottled it!

The age-old mystery was unlocked thanks to some novel bacteria plucked from the North Norfolk coast.Prof Andrew Johnston and his team at UEA isolated this microbe from the mud at Stiffkey saltmarsh to identify and extract the single gene responsible for the emission of the strong-smelling gas, dimethyl sulphide (DMS). "On bracing childhood visits to the seaside we were always told to 'breathe in that ozone, it's good for you'," said Prof Johnston. "But we were misled, twice over. Firstly because that distinctive smell is not ozone, it is dimethyl sulphide. And secondly, because inhaling it is not necessarily good for you."DMS is a little known but important gas. Across the world's oceans, seas and coasts, tens of millions of tonnes of it are released by microbes that live near plankton and marine plants, including seaweeds and some salt-marsh plants. The gas plays an important role in the formation of cloud cover over the oceans, with major effects on climate. Indeed, the phenomenon was used by James Lovelock as a plank to underpin his 'Gaia hypothesis'. DMS is also a remarkably effective food marker for ocean-going birds such as shearwaters and petrels. It acts as a homing scent -- like Brussels sprouts at the Christmas dinner table! - and the birds sniff out their plankton food in the lonely oceans at astonishingly low concentrations.Scientists have known about DMS for many years but the genes responsible for its production have never before been identified. The new findings will be published in the journal Science on Friday February 2."By isolating a single gene from a bacterium collected from the mud of Stiffkey marshes, we deduced that the mechanisms involved in DMS production differ markedly from those that had been predicted," said Prof Johnston. "And we discovered that other, wholly unexpected bacteria could also make that seaside smell."The discovery adds to the diverse list of Stiffkey's claims to fame. The small coastal village is renowned for its 'Stewkey Blue' cockles and was also the home of Henry Williamson, author of 'Tarka the Otter'.A more controversial figure from Siffkey's past was its rector, Rev Harold Davidson, who was defrocked in 1932 after allegedly 'cavorting with' London prostitutes. He later joined a circus and died after being mauled to death by a lion in Skegness. The UEA scientists are hoping to avoid such a fate, said Prof Johnston.

Ozone Holes

December 14, 2006

https://www.sciencedaily.com/releases/2006/12/061212091901.htm

Pollution Knows No Borders

Plumes of ozone-producing pollution routinely cross political boundaries, influence local regulatory efforts and impact health and the environment, according to a team of atmospheric chemists trying to trace ozone in the lower atmosphere.

"There is a connection between pollution in Mexico City and in Houston, Texas," says Dr. Anne M. Thompson, professor of meteorology, Penn State. "The spring, which is the end of the dry season, is the beginning of field burning. That is when the winds move toward the U.S. so that Houston gets an added boost of ozone into their cycle." Thompson and a large team of researchers carries out a program launching ozonesondes in experiments that measure ozone and other variables in the atmosphere. The ozonesonde instrument packages are carried into the air by weather balloons. Recently, Thompson's team tested the air in the Mexico City area and Houston, Texas, and in Richland, Wash. Pollution in Mexico City affects U.S. Gulf Coast areas including Houston. Richland is affected by pollution coming across the Pacific Ocean from Asia. The airborne instruments measure temperature, relative humidity, elevation, location -- if a geographic positioning system instrument is aboard -- and ozone. The balloons reach an altitude of between 22 and 25 miles before they explode due to decreased pressure and the instrument package falls to Earth and shatters. Ozone is manufactured in the atmosphere by sunlight working on a combination of hydrocarbons, carbon monoxide and nitrogen oxides, all chemicals created by burning organic fuels. Ozone can be either a good chemical or a pollutant, depending on where it occurs in the atmosphere. In the upper atmosphere, ozone provides a shield against the suns ultra violet radiation, but in the lower atmosphere, it is a pollutant that causes health problems and can damage crops. "In August, over Mexico City, we recorded a level of 150 parts per billion of ozone," Thompson told attendees at the fall meeting of the American Geophysical Union in San Francisco, today (Dec. 11). "In the U.S., the standard is 80 parts per billion averaged over eight hours." With the Mexican/Houston experiment, the researchers did find a link between ozone levels in the Mexico City area and levels a few days later in Houston on a number of occasions. The effect was strongest in March when Mexico City air was stagnant and the normal air flow is northeast toward Houston. The researchers have not completed analysis of the Richland experiment. Tracking ozone transport and pollution are not as simple as finding a pollution source and tracking it. Natural factors play into the equation. "Summer rains are supposed to wash pollution out of the air," says Thompson. "But, because of lightning and pollution pumped up by thunderstorms, measurements over Mexico were still high in August." Lightning occurs more frequently in the tropics than in other areas of the globe. The high amounts of energy released by a lightning strike or a cloud-to-cloud lightning flash produces nitric oxide, a chemical that leads to ozone formation. The amount of ozone produced can be significant and is related to the level of lightning activity. Information from only a few locations will not supply sufficient data to understand global ozone production. "Each time we send a balloon up, we lose the package," says the Penn State scientist. "Each package is $1,000."To gather as much information as possible, the IONS-06 (INTEX Ozonesonde Network Study) project -- part of the broader Intercontinental Transport Experiment (INTEX) that includes aircraft and measures other atmospheric chemicals -- followed on the IONS-04 project. IONS-06 incorporates data from across North America with a variety of researchers and research sites from Rhode Island to California and from Mexico to Ontario, Canada. The project also includes a variety of government agencies -- NASA, Jet Propulsion Laboratory, National Oceanic and Atmospheric Administration, Los Alamos National Laboratory and Environment Canada/Meteorologic Service of Canada -- as well as the universities. Beside Thompson, other Penn State researchers were S.K. Miller, research associate; J.E. Yorks and R. B. Long, graduate students; and M.J. Madigan, undergraduate student. Researchers from other institutions included J.C. Witte and T.L Kucsera, NASA Goddard Space Flight Center; B. Leer, University of Houston; and G. Morris, Valparaiso University. NASA funded Thompson's portion of the IONS-06 project.

Ozone Holes

November 28, 2006

https://www.sciencedaily.com/releases/2006/11/061128083906.htm

Nitrogen Oxide Pollutants Have Declined Over The Eastern United States Since 1999

Nitrogen oxides (known as NOx) emitted by fossil fuel combustion play a crucial role in producing ground level ozone, a pollutant hazardous to human health that contributes to smog over urban areas.

In 1999, coal-burning power plants represented about 25 percent of U.S. manmade NOx emissions, and recent pollution control measures by utility companies have sought to reduce NOx emissions.Kim et al. analyzed satellite data and air quality model simulations to document regional trends in emissions. They found a declining regional trend in NOx emissions in the eastern United States. Over the Ohio River Valley, where power plants dominate NOx emissions, NOx pollution has decreased by 40 percent since 1999.This decrease is larger than that seen in the northeast urban corridor. The researchers' model simulations predict lower ground-level ozone concentrations as a result of these NOx emission reductions. They suggest that further substantive reductions in eastern U.S. NOx levels will require decreases in mobile sources of Nox emissions, such as car exhaust.Title: Satellite-observed US power plant NOx emission reductions and their impact on air qualityAuthors: S.-W. Kim, S. A. McKeen, G. J. Frost, and E.-Y. Hsie: Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, U.S.A.; also at Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, U.S.A.; A. Heckel, A. Richter, J. P. Burrows: Institute of Environmental Physics and Institute of Remote Sensing, University of Bremen, Germany; M. K. Trainer: Chemical Sciences Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, U.S.A; S. E. Peckham and G. A. Grell: Global Systems Division, Earth System Research Laboratory, National Oceanic and Atmospheric Administration, Boulder, Colorado, U.S.A.; also at Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, Colorado, U.S.A.Source: Geophysical Research Letters (GRL) paper 10.1029/2006GL027749, 2006

Ozone Holes

November 22, 2006

https://www.sciencedaily.com/releases/2006/11/061120182053.htm

Level Of Important Greenhouse Gas Has Stopped Growing: Seven-year Stabilization Of Methane May Slow Global Warming

Scientists at UC Irvine have determined that levels of atmospheric methane – an influential greenhouse gas – have stayed nearly flat for the past seven years, which follows a rise that spanned at least two decades.

This finding indicates that methane may no longer be as large a global warming threat as previously thought, and it provides evidence that methane levels can be controlled. Scientists also found that pulses of increased methane were paralleled by increases of ethane, a gas known to be emitted during fires. This is further indication that methane is formed during biomass burning, and that large-scale fires can be a big source of atmospheric methane.Professors F. Sherwood Rowland and Donald R. Blake, along with researchers Isobel J. Simpson and Simone Meinardi, believe one reason for the slowdown in methane concentration growth may be leak-preventing repairs made to oil and gas lines and storage facilities, which can release methane into the atmosphere. Other reasons may include a slower growth or decrease in methane emissions from coal mining, rice paddies and natural gas production.“If one really tightens emissions, the amount of methane in the atmosphere 10 years from now could be less than it is today. We will gain some ground on global warming if methane is not as large a contributor in the future as it has been in the past century,” said Rowland, Donald Bren Research Professor of Chemistry and Earth System Science, and co-recipient of the 1995 Nobel Prize for discovering that chlorofluorocarbons in products such as aerosol sprays and coolants were damaging the Earth’s protective ozone layer.The methane research will be published in the Nov. 23 online edition of Geophysical Research Letters.Methane, the major ingredient in natural gas, warms the atmosphere through the greenhouse effect and helps form ozone, an ingredient in smog. Since the Industrial Revolution in the late 1700s, atmospheric methane has more than doubled. About two-thirds of methane emissions can be traced to human activities such as fossil-fuel extraction, rice paddies, landfills and cattle. Methane also is produced by termites and wetlands.Scientists in the Rowland-Blake lab use canisters to collect sea-level air in locations from northern Alaska to southern New Zealand. Then, they measure the amount of methane in each canister and calculate a global average.From December 1998 to December 2005, the samples showed a near-zero growth of methane, ranging from a 0.2 percent decrease per year to a 0.3 percent gain. From 1978 to 1987, the amount of methane in the global troposphere increased by 11 percent – a more than 1 percent increase each year. In the late 1980s, the growth rate slowed to between 0.3 percent and 0.6 percent per year. It continued to decline into the 1990s, but with a few sharp upward fluctuations, which scientists have linked to non-cyclical events such as the eruption of Mt. Pinatubo in 1991 and the Indonesian and boreal wildfires in 1997 and 1998.Along with methane, the UCI scientists also measured levels of other gases, including ethane, a by-product of petroleum refining that also is formed during biomass burning, and perchloroethylene, a chlorinated solvent often used in the dry cleaning process. Ethane levels followed the peaks and valleys of methane over time, but perchloroethylene had a different pattern. This finding provides evidence that biomass burning on occasion, as in Indonesia in 1997 and Russia in 1998, can be a large source of atmospheric methane.The researchers say there is no reason to believe that methane levels will remain stable in the future, but the fact that leveling off is occurring now indicates that society can do something about global warming. Methane has an atmospheric lifetime of about eight years. Carbon dioxide – the main greenhouse gas that is produced by burning fossil fuels for power generation and transportation – can last a century and has been accumulating steadily in the atmosphere.“If carbon dioxide levels were the same today as they were in 2000, the global warming discussion would leave the front page. But to stabilize this greenhouse gas, we would have to cut way back on emissions,” Rowland said. “Methane is not as significant a greenhouse gas as carbon dioxide, but its effects are important. The world needs to work hard to reduce emissions of all greenhouse gases.”NASA and the Gary Comer Abrupt Climate Change Fellowship supported this research.

Ozone Holes

November 8, 2006

https://www.sciencedaily.com/releases/2006/11/061108100414.htm

Volcanic Aerosol Clouds And Gases Lead To Ozone Destruction

Volcanic eruptions destroy ozone and create 'mini-ozone holes', according to two new studies by researchers at the Universities of Cambridge and Oxford.

The new research, spearheaded by Dr Genevieve Millard at the Department of Earth Sciences, University of Cambridge, discovered that volcanic gases released during eruptions accelerate reactions that lead to ozone destruction. The researchers found that even relatively small volcanic eruptions can destroy ozone and create localised 'holes' in the stratosphere. Previously, scientists had concentrated on the climatic effects of the tiny particles of volcanic sulphate created from the sulphur dioxide gas emitted during an eruption. For the first time, analysing data from a 2000 eruption of the Hekla volcano, Iceland, the researchers discovered that volcanic gases may also lead to the formation of ice and nitric acid particles. This is a critical finding as these particles 'switch on' volcanic chorine gases, accelerating reactions that lead to ozone destruction.Dr Millard said, "We have shown for the first time that volcanic eruptions which penetrate the stratosphere can lead to the formation of the type of clouds that promote reactions with volcanic chlorine gases - gases that destroy stratospheric ozone and lead to the formation of 'mini-ozone holes'." The ozone losses due to the small eruption at Hekla lasted for about two weeks, and eventually returned to normal levels. This is the first time that people have observed the complete removal of local ozone following a volcanic eruption. "Now we want to find out what might happen to the ozone layer after a much larger eruption," said Dr David Pyle, University of Oxford, project coordinator. "For example, is there significant loss of ozone and increased ultra-violet radiation at low latitudes following large explosive eruptions? We want to understand this, so that we can have a better picture both of what might have happened in the past, and of what may happen in the future".

Ozone Holes

October 20, 2006

https://www.sciencedaily.com/releases/2006/10/061019162053.htm

Antarctic Ozone Hole Is A Double Record Breaker

NASA and National Oceanic and Atmospheric Administration (NOAA) scientists report this year's ozone hole in the polar region of the Southern Hemisphere has broken records for area and depth.

The ozone layer acts to protect life on Earth by blocking harmful ultraviolet rays from the sun. The "ozone hole" is a severe depletion of the ozone layer high above Antarctica. It is primarily caused by human-produced compounds that release chlorine and bromine gases in the stratosphere. "From September 21 to 30, the average area of the ozone hole was the largest ever observed, at 10.6 million square miles," said Paul Newman, atmospheric scientist at NASA's Goddard Space Flight Center, Greenbelt, Md. If the stratospheric weather conditions had been normal, the ozone hole would be expected to reach a size of about 8.9 to 9.3 million square miles, about the surface area of North America. The Ozone Monitoring Instrument on NASA's Aura satellite measures the total amount of ozone from the ground to the upper atmosphere over the entire Antarctic continent. This instrument observed a low value of 85 Dobson Units (DU) on Oct. 8, in a region over the East Antarctic ice sheet. Dobson Units are a measure of ozone amounts above a fixed point in the atmosphere. The Ozone Monitoring Instrument was developed by the Netherlands' Agency for Aerospace Programs, Delft, The Netherlands, and the Finnish Meteorological Institute, Helsinki, Finland. Scientists from NOAA's Earth System Research Laboratory in Boulder, Colo., use balloon-borne instruments to measure ozone directly over the South Pole. By Oct. 9, the total column ozone had plunged to 93 DU from approximately 300 DU in mid-July. More importantly, nearly all of the ozone in the layer between eight and 13 miles above the Earth's surface had been destroyed. In this critical layer, the instrument measured a record low of only 1.2 DU., having rapidly plunged from an average non-hole reading of 125 DU in July and August. "These numbers mean the ozone is virtually gone in this layer of the atmosphere," said David Hofmann, director of the Global Monitoring Division at the NOAA Earth System Research Laboratory. "The depleted layer has an unusual vertical extent this year, so it appears that the 2006 ozone hole will go down as a record-setter." Observations by Aura's Microwave Limb Sounder show extremely high levels of ozone destroying chlorine chemicals in the lower stratosphere (approximately 12.4 miles high). These high chlorine values covered the entire Antarctic region in mid to late September. The high chlorine levels were accompanied by extremely low values of ozone. The temperature of the Antarctic stratosphere causes the severity of the ozone hole to vary from year to year. Colder than average temperatures result in larger and deeper ozone holes, while warmer temperatures lead to smaller ones. The NOAA National Centers for Environmental Prediction (NCEP) provided analyses of satellite and balloon stratospheric temperature observations. The temperature readings from NOAA satellites and balloons during late-September 2006 showed the lower stratosphere at the rim of Antarctica was approximately nine degrees Fahrenheit colder than average, increasing the size of this year's ozone hole by 1.2 to 1.5 million square miles. The Antarctic stratosphere warms by the return of sunlight at the end of the polar winter and by large-scale weather systems (planetary-scale waves) that form in the troposphere and move upward into the stratosphere. During the 2006 Antarctic winter and spring, these planetary-scale wave systems were relatively weak, causing the stratosphere to be colder than average. As a result of the Montreal Protocol and its amendments, the concentrations of ozone-depleting substances in the lower atmosphere (troposphere) peaked around 1995 and are decreasing in both the troposphere and stratosphere. It is estimated these gases reached peak levels in the Antarctica stratosphere in 2001. However, these ozone-depleting substances typically have very long lifetimes in the atmosphere (more than 40 years). As a result of this slow decline, the ozone hole is estimated to annually very slowly decrease in area by about 0.1 to 0.2 percent for the next five to 10 years. This slow decrease is masked by large year-to-year variations caused by Antarctic stratosphere weather fluctuations. The recently completed 2006 World Meteorological Organization/United Nations Environment Programme Scientific Assessment of Ozone Depletion concluded the ozone hole recovery would be masked by annual variability for the near future and the ozone hole would fully recover in approximately 2065. "We now have the largest ozone hole on record," said Craig Long of NCEP. As the sun rises higher in the sky during October and November, this unusually large and persistent area may allow much more ultraviolet light than usual to reach Earth's surface in the southern latitudes.

Ozone Holes

October 16, 2006

https://www.sciencedaily.com/releases/2006/10/061016122030.htm

Identifying A New Generation Of Byproducts From Water Disinfection

California scientists have identified a "new generation" of by-products of the disinfection processes used to purify drinking water at municipal water treatment plants. Such compounds, which wind up in drinking water, are termed disinfection byproducts (DBPs). The U. S. Environmental Protection Agency currently regulates some as potential health risks.

Stuart W. Krasner and colleagues tested water from 12 treatment plants specifically chosen for waters high in DBP precursors and natural organic matter in order to facilitate detection of DBPs. They tested the water for levels of regulated DBPs and 50 unregulated DBPs regarded as posing the greatest health risks. Their report is scheduled for the Dec. 1 issue of the semi-monthly ACS journal, Environmental Science & Technology.Some treatment plants have switched from chlorine to alternative disinfectants such as ozone, chlorine dioxide and chloramines to minimize formation of DBPs. The alternative disinfectants minimized formation of some regulated DBPs. However, researchers found higher levels of other regulated and unregulated DBPs in water from plants using alternative disinfectants.The researchers also found 28 previously unreported DBPs. Toxicity studies are needed to help determine the health implications of these emerging DBPs, researchers indicated.

Ozone Holes

October 6, 2006

https://www.sciencedaily.com/releases/2006/09/060929093908.htm

Strong Winds Trigger Increases In Ozone Destroying Gases In Upper Stratosphere

A surprising new University of Colorado at Boulder study indicates winds circling high above the far Northern Hemisphere have a much greater impact on upper stratospheric ozone levels than scientists had thought.

According to Associate Professor Cora Randall of CU-Boulder's Laboratory for Atmospheric and Space Physics, the winds allowed near-record amounts of ozone-destroying nitrogen oxide gases, collectively known as NOx, to descend some 30 miles to the top of Earth's stratosphere in March 2006. Because NOx destroys ozone, which heats up the stratosphere by absorbing ultraviolet radiation, the naturally occurring gases could trigger atmospheric changes that could have unanticipated climate consequences, she said. In February 2006, winds in the polar upper stratospheric vortex -- a massive winter low-pressure system that confines air over the Arctic region -- sped up to rival the strongest such winds on record, said Randall. The only time more NOx was observed in the upper stratosphere was in the winter of 2003-04, when huge solar storms bombarded the region with energetic particles, triggering up to a 60 percent reduction in ozone molecules, said Randall. "We knew strong winds would lead to more NOx in the stratosphere if there were solar storms," said Randall, who also is associated with CU-Boulder's atmospheric and oceanic sciences department. "But seeing that much NOx come down into the stratosphere when the sun was essentially quiet was amazing." Randall is the chief author of a paper on the subject being published in the Sept. 27 online issue of Geophysical Research Letters, published by the American Geophysical Union. Researchers from the University of Waterloo in Ontario, Canada, and the University of Michigan also contributed to the study. The upper stratosphere lies several miles higher than the ozone hole region, which forms in the lower stratosphere and is caused by emissions of man-made gases like chlorine and bromine over the decades that are still gobbling up ozone molecules, she said. Because there is significantly less ozone in the upper stratosphere, the ozone-destroying NOx gases are unlikely to cause immediate health threats, such as increases in skin cancer, she said. But the destructive NOx gases -- created above the stratosphere when sunlight or energetic particles break apart oxygen and nitrogen molecules -- appear to be important players in controlling the temperature of Earth's middle atmosphere, according to Randall. "If human-induced climate change leads to changes in the strength of the polar vortex, which is what scientists predict, we'll likely see changes in the amount of NOx descending into the stratosphere," said Randall. "If that happens, more stratospheric NOx might become the rule rather than the exception. "The atmosphere is part of a coupled system, and what affects one layer of the atmosphere can influence other layers in surprising ways," she said. "We will only be able to predict and understand the consequences of human activities if we study the entire system as a whole, and not just in parts." The 2006 increases of NOx in the upper stratosphere occurred over the Arctic and the northern areas of North America and Europe, according to the paper authors. The work was funded by NASA and the Canadian Space Agency. The research team used data from Canadian and United States satellites, including the Canadian Atmospheric Chemistry Experiment. Co-authors on the paper included CU-Boulder researchers Lynn Harvey and Cynthia Singleton, Peter Bernath and Chris Boone from the University of Waterloo and Janet Kozyra from the University of Michigan.

Ozone Holes

October 3, 2006

https://www.sciencedaily.com/releases/2006/10/061002215000.htm

Record Ozone Loss During 2006 Over South Pole

Ozone measurements made by ESA’s Envisat satellite have revealed the ozone loss of 40 million tonnes on 2 October 2006 has exceeded the record ozone loss of about 39 million tonnes for 2000.

Ozone loss is derived by measuring the area and the depth of the ozone hole. The size of this year’s ozone hole is 28 million square km, nearly as large as the record ozone hole extension during 2000, and the depth of the ozone hole is around 100 Dobson Units, rivalling the record low ozone values in 1998. This year’s record ozone loss was reached because these two measurements occurred during the same time period. (A Dobson unit is a unit of measurement that describes the thickness of the ozone layer in a column directly above the location being measured.)  "Such significant ozone loss requires very low temperatures in the stratosphere combined with sunlight. This year’s extreme loss of ozone can be explained by the temperatures above Antarctica reaching the lowest recorded in the area since 1979," ESA Atmospheric Engineer Claus Zehner said. Ozone is a protective layer found about 25 kilometres above us mostly in the stratospheric stratum of the atmosphere that acts as a sunlight filter shielding life on Earth from harmful ultraviolet rays. Over the last decade the ozone level has lowered by about 0.3% per year on a global scale, increasing the risk of skin cancer, cataracts and harm to marine life. The thinning of the ozone is caused by the presence of pollutants in the atmosphere such as chlorine, originating from man-made pollutants like chlorofluorocarbons (CFCs), which have still not vanished from the air despite being banned under the Montreal Protocol (1987). During the southern hemisphere winter, the atmospheric mass above the Antarctic continent is kept cut off from exchanges with mid-latitude air by prevailing winds known as the polar vortex. This leads to very low temperatures, and in the cold and continuous darkness of this season, polar stratospheric clouds are formed that contain chlorine. As the polar spring arrives, the combination of returning sunlight and the presence of polar stratospheric clouds leads to splitting of chlorine compounds into highly ozone-reactive radicals that break ozone down into individual oxygen molecules. A single molecule of chlorine has the potential to break down thousands of molecules of ozone. The ozone hole, first recognised in 1985, typically persists until November or December, when the winds surrounding the South Pole (polar vortex) weaken, and ozone-poor air inside the vortex is mixed with ozone-rich air outside it. Envisat, the largest Earth observation satellite ever built, can localise ozone depletion and track its changes, enabling the rapid estimation of UV radiation as well as providing forecasting. The three atmospheric instruments aboard Envisat are the Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY), the global ozone monitoring by occultation of stars (GOMOS) sensor and the Michelson interferometer for passive atmospheric sounding (MIPAS). In the framework of GMES (Global Monitoring of the Environment and Security), ESA has backed a project named TEMIS (Tropospheric Emission Monitoring Internet Service) that provides operational ozone and UV radiation monitoring based on SCIAMACHY and GOME-1 data. The ozone-monitoring data provided by these instruments span a time period of 11 years, which will be extended by the upcoming MetOp satellite series.The first MetOp satellite in the series of three is scheduled to be launched in 2006 and will assist climate researchers in monitoring ozone levels and other atmospheric parameters. MetOp – Europe’s first polar-orbiting satellite and a mission dedicated to operational meteorology – will include a next-generation ozone-monitoring instrument called GOME-2, intended to guarantee continuity of observation of this vital environmental factor well into the following decades. "Long-term measurements of ozone levels are of key importance for being able to monitor the ozone’s predicted recovery, which is currently estimated to take place by around 2060," Zehner said.

Ozone Holes

September 28, 2006

https://www.sciencedaily.com/releases/2006/09/060928095349.htm

As Ozone Hole Approaches Annual Peak, NASA Scientists Reveal Latest Information And Images

In 1987, the United States joined several other nations in signing the Montreal Protocol, an international treaty designed to protect the Earth's ozone layer by phasing out the production of a number of substances believed to be responsible for ozone depletion.

NASA's sub-orbital measurements, captured by aircraft- and ground-based sensors, provided much of our basic initial understanding of the cause and effect between anthropogenic, or man-made, chlorofluorocarbons (CFCs), and the Antarctic ozone hole. Now, as the Antarctic ozone hole approaches its annual peak nineteen years later, NASA scientists are using the latest tools to determine what effect the ban on CFCs and related chemicals has had and how long we will have to wait for a full ozone layer recovery. The agency is sharing the latest information and satellite images of the ozone hole with the public on its Ozone Watch Web site (CFCs are non-toxic and non-flammable, and were used for popular household products such as air conditioner and refrigerator coolant, aerosol hairsprays, and cleaning solvents. Researchers confirmed in the 1970s that CFCs were escaping high in the air into the stratosphere (6-30 miles above the Earth's surface) where they destroy "good" ozone, a colorless gas that protects us from the most harmful forms of solar radiation. This realization eventually led to the global ban on these pollutants.Each fall, the area of the Antarctic atmosphere called the "ozone hole" opens up in mid-August during the onset of spring in the Southern Hemisphere and peaks in late September or early October. The ozone "hole" is not a hole in the literal sense where no ozone exists, but a region above the Antarctic where significant amounts of ozone are destroyed based on the temperature and amount of ozone-depleting gases in the air. Though it is still too early to tell, the 2006 Antarctic ozone hole has not shown any substantial signs of recovery. "This region that we look at is over 9 million square miles, now that's pretty large," said Paul Newman, a senior research scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. Newman, who has used NASA satellite technology to study how much impact the ban is having on the size of the ozone hole says, "That's larger than the entire continent of North America. So this is a very large thing that we're looking at."Newman and other scientists keep tabs on ozone hole recovery using several satellites including Aura, which carries four instruments continuously capturing data on the atmosphere, most notably the Ozone Monitoring Instrument (OMI), built by the Netherlands and Finland in collaboration with NASA. Aura is part of NASA's Earth Observing System fleet of satellites.Intense ultraviolet radiation in the upper atmosphere gives birth to ozone. The radiation breaks typical oxygen molecules down into free-floating oxygen atoms. Ozone is created when a free oxygen atom joins with an oxygen molecule to form a molecule of ozone. Chemical reactions involving such familiar compounds as chlorine, bromine, nitrogen, and hydrogen can destroy ozone. "The Antarctic ozone hole will reach sizes on the order of 8-10 million square miles nearly every year until about 2018 or so," said Newman. "Around 2018, things should slowly start improving, and somewhere between 2020 and 2025, we'll be able to detect that the ozone hole is actually beginning to decrease in size. Eventually the ozone hole will go back to its normal level around 2070 or so. So we will soon see what this year's peak will reveal about the ozone hole and our ability to predict its development and recovery."

Ozone Holes

September 22, 2006

https://www.sciencedaily.com/releases/2006/09/060915203344.htm

Solutions To Pollution, Ozone Explored By Atmospheric Scientists

University of Houston scientists are joining more than 200 researchers from 60 institutions in the Texas Air Quality Study-II (TexAQS-II), to help alleviate the negative impact of air pollution on public health and economic development.

A scientific investigation into the key air quality issues of the eastern half of Texas, TexAQS-II is an initiative led by the National Oceanic and Atmospheric Administration (NOAA), using $2 million appropriated to the Environmental Protection Agency (EPA), to collect and model data in order to develop a more accurate profile of the region's atmosphere. UH's measurement and modeling programs in the department of geosciences are playing a large role in TexAQS-II, leading the way to create a Gulf Coast Air Quality Model. With one of the most comprehensive measurement ground sites, UH is home to the Moody Tower Atmospheric Chemistry Facility -- one of three super sites that offer the most all-inclusive chemical and meteorological measurement platforms measuring more than 50 variables. During the TexAQS-II initiative, the UH scientists running the Moody Tower facility are collaborating with more than 40 visiting scientists from several different universities and national labs. As the only ground site of the three super sites, the Moody Tower facility is operational 24 hours a day, seven days a week and offers the most representative sample of what the average person typically breathes in on a daily basis. The other two super sites are NOAA-owned planes and boats, offering observation from the air and water. "Since we are high up at 18 stories on the roof of UH's Moody Tower dormitory, we can offer a larger footprint of what is actually going on," said Bernhard Rappenglueck, associate professor of atmospheric science at UH. "From up here, we avoid local influences on the ground, such as cars and trucks driving by that would skew results, and can also detect pollutants not just from the Houston area, but even as far away as Mexico." The Moody Tower vantage point also allows UH scientists to observe and measure the land and sea breeze effects, where during the course of a day aged pollution from the Port of Houston floats to Galveston and then blows back to Houston. The amount and diversity of chemicals measured from this UH super site number in the hundreds, including hydrocarbons from factories burning fossil fuel and from vegetation under environmental stress, carbon monoxide and formaldehyde from vehicle exhaust and a wide range of other harmful elements. The several combinations of these compounds that come together to form ozone, however, receive the most focus from researchers. "Houston is ripe for ozone," said Barry Lefer, assistant professor of atmospheric science at UH. "Very basically, sunlight, nitrogen oxide and hydrocarbons react to make ozone, and water vapor helps that process along. So, with no short supply of sun and humidity, combined with all the exotic compounds of the chemical industry, Houston is not surprisingly one of the worst with regard to ozone noncompliance levels across the country." Lefer stresses that the efforts of TexAQS-II will be a good test to see how industry has cleaned up since the first TexAQS initiative six years ago. In this second air quality study, he said, UH scientists are determining what the photochemical processes are, which ones are most important and what the best strategy is to solve the problems. Along with the myriad measurement tools, gauges and computers on the roof of Moody Tower, weather balloons containing instruments to monitor ozone and other air quality factors are being launched through the end of September and are transmitting data electronically back to labs at UH before parachuting to the ground. From the UH super site, Rappenglueck's students are launching two to six of them each day, while Lefer's graduate students will launch 45 of these weather balloons near various refinery and petrochemical facilities. These balloon launches are a first for Houston, with Lake Charles, La., being the closest until now, and will help with ozone and weather forecasting. Complementing Lefer and Rappenglueck's Atmospheric Chemistry Measurement Group, UH's modeling and forecasting arm -- the Institute for Multi-dimensional Air Quality Studies -- will extend the Moody Tower super site measurements by running them through UH atmospheric science professor Daewon Byun's sophisticated computational models to pinpoint what works and what doesn't. If Byun's models accurately work to forecast ozone and other air quality conditions with his measurement colleagues' data, then the existing UH super site and balloon efforts can be applied to other sites. However, if the model does not work properly, then Byun can find out what to fix -- either on the measurement or modeling side -- to perfect the process, such as getting the correct balance of chemistry, emissions and weather measurements. "The complementary nature of modeling and measurement is key to atmospheric science," Byun said. "One of UH's main goals in the TexAQS-II initiative is for my modeling to extend the measurement efforts of my colleagues so that we can work together to reduce dangerous ozone levels and air pollution."

Ozone Holes

September 21, 2006

https://www.sciencedaily.com/releases/2006/09/060921094440.htm

'Imported' Pollution Tied To Poor Air Quality In Texas In 2004

Scientists using NASA satellites and other data including computer models and ground sensors have demonstrated that pollutants traveling even thousands of miles can impact air quality.

The study concludes that ozone pollution levels increased significantly in the air above Houston on July 19 and 20, 2004. Researchers attribute this increase in part as a result of smoke transported into the area over the course of a week from forest fires raging in Alaska and Canada. The study is one of only a few that has quantitatively examined the impact of remotely generated pollutants on air quality in the lower atmosphere. As part of a NASA-led field research project in the summer of 2004, researchers sampled a variety of trace gases and aerosols -- tiny particles suspended in the air -- across North America. During the time of the study, forest fires in western Canada and eastern Alaska were consuming more acres than at any time during the last 50 years. Meteorological conditions carried smoke from these intense fires eastward and southward to the U.S. Gulf Coast."The combination of our balloon-borne ozone data and observations by NASA satellites, aircraft, and a network of ground stations provided unprecedented insight into the origins of locally poor air quality in Houston on those two days," said study lead author Gary Morris of Valparaiso University, Valparaiso, Ind.The researchers relied on imagery from NASA's Moderate Resolution Imaging Spectroradiometer on the Terra satellite, aerosol data from the Total Ozone Mapping Spectrometer satellite, and carbon monoxide data from the Atmospheric Infrared Sounder on the Aqua spacecraft to track the an air mass from the region of forest fires in western Canada and eastern Alaska on July 12-13, 2004. The air mass traveled across Canada, through the mid-western United States, and all the way to Houston, arriving there on July 19."We found that with the arrival of the pollutants associated with these forest fires, ozone levels increased between 50-100 percent in the first 5 kilometers over Houston," said Morris. Meteorological conditions, the smoke from the distant forest fires, and the typical urban pollution generated in the Houston area provided a potent mix for increasing local ozone concentrations. The scientists believe that such pollution episodes will continue. Understanding the transport and transformation of gases and aerosols over long distances is needed for improved understanding and air quality forecasting."This event highlights the critical role imported sources can have on local air quality,” said Morris. Balloon-borne data and ground observations combined with data from NASA's suite of satellites and computer models will continue to advance our understanding of the impact of pollutants on air quality. Such information will help enable environmental managers to improve air quality forecasts and propose more effective air quality solutions.This study appears in the September issue of the American Geophysical Union's Journal of Geophysical Research - Atmospheres. It was sponsored by NASA and included participants from several federal, academic and international institutions.

Ozone Holes

August 31, 2006

https://www.sciencedaily.com/releases/2006/08/060830215811.htm

Atmospheric Ozone Recovering In Mid-latitudes, Report Shows

Concentrations of atmospheric ozone -- which protects Earth from the sun’s ultraviolet radiation -- are showing signs of recovery in the most important regions of the stratosphere above the mid-latitudes in both the Northern and Southern hemispheres, a new study shows.

Researchers attribute the improvement to both a reduction in ozone-depleting chemicals phased out by the global Montreal Protocol treaty and its amendments and to changes in atmospheric transport dynamics. The study, funded by NASA, is the first to document a difference among stratospheric regions in ozone-level improvement and to establish a cause-and-effect relationship based on direct measurements by multiple satellite and ground-based, ozone-monitoring systems.“We do think we’re on the road to recovery of stratospheric ozone, but what we don’t know is exactly how that recovery will happen,” said Derek Cunnold, a professor of earth and atmospheric sciences at the Georgia Institute of Technology. “Many in the scientific community think it will be at least 50 years before ozone levels return to the pre-1980 levels when ozone began to decline.”The research results will be published Sept. 9, 2006 in the American Geophysical Union’s Journal of Geophysical Research—Atmospheres. Georgia Tech research scientist Eun-Su Yang led the study in close collaboration with Cunnold, Ross Salawitch of NASA's Jet Propulsion Laboratory at the California Institute of Technology, M. Patrick McCormick and James Russell III of Hampton University, Joseph Zawodny of NASA Langley Research Center, Samuel Oltmans of the NOAA Earth System Research Laboratory and Professor Mike Newchurch at the University of Alabama in Huntsville.The study’s data indicate that atmospheric ozone has stopped decreasing in one region and is actually increasing in the other of the two most important lower regions of the stratosphere.Scientists attribute the stabilization of ozone levels in the past decade in the 11- to 15-mile (18- to 25-kilometer) altitude region to the Montreal Protocol, enacted in 1987, and its amendments. The treaty phased out the use of ozone-depleting chemicals, including chlorofluorocarbons (CFCs) emitted from such sources as spray-can propellants, refrigerator coolants and foam insulation.In the 7- to 11-mile (11- to 18-kilometer) region, the researchers link a slight increase in ozone to changes in atmospheric transport – perhaps caused by natural variability or human-induced climate warming – rather than atmospheric chemistry. The changes in this altitude range – below the region where ozone-depleting gases derived from human activity are thought to cause ozone depletion – contribute about half of the overall-measured improvement, researchers said.“There is now widespread agreement in the scientific community that ozone is leveling off in the 18- to 25-kilometer region of the stratosphere because of the Montreal Protocol,” Cunnold said. “And we believe there is some tendency toward an increase in ozone in this region, though further study is needed to be certain.“In the 11- to 18-kilometer region, ozone is definitely increasing because of changes in atmospheric dynamics and transport not related to the Montreal Protocol,” he added. “But we don’t know the long-term effect this change will have in this region.”Other recent studies complement these new findings. Among them are a study published in 2003 in the Journal of Geophysical Research, which reported a slowdown in the ozone depletion rate in the upper stratosphere at about 22 to 28 miles altitude (35 to 45 kilometers). Newchurch at the University of Alabama in Huntsville led this study in collaboration with: Cunnold, his former Ph.D. advisor; Yang, his former Ph.D. student; and other prominent scientists. Newchurch is also an author on the current paper.More recently, a study published in the journal Nature on May 3, 2006 indicated a stabilization and slight increase in the total-column stratospheric ozone in the past decade. This work, led by Betsy Weatherhead at the University of Colorado at Boulder, relied on satellite and ground-based ozone data used in 14 modeling studies done by researchers around the world. She and her colleagues also attributed the changes to the Montreal Protocol, but could not separate treaty-related changes from transport-related changes because of limited information available on ozone variations by height.In the current study, Yang, Cunnold and their co-authors reached their conclusions based on satellite and ground-based atmospheric ozone measurements. They analyzed a tremendous amount of data from three extremely accurate NASA satellite’s instruments (SAGE I and II and HALOE) that began collecting data in 1979 and continued until 2005, with the exception of a three-year period in the early 1980s. Ground-based ozone measurements taken by NASA and NOAA from 1979 to 2005 and balloons provided essential complementary data for the study, Yang said. The satellites and the balloons measured ozone levels by atmospheric region. The ground-based data recorded measurements for the total ozone column.“The ground-based measurements were especially important for the lower atmosphere because satellites can have difficulty in sensing the lowest regions,” Yang said.Salawitch, a senior research scientist at NASA’s Jet Propulsion Laboratory, noted: “Our study provides a quantitative measure of a key fingerprint that is lacking in earlier studies -- the response of the ozone layer as function of height. We reconcile the height-dependent response with observations from other instruments that record variations in total-column ozone."To accurately attribute the ozone level changes to the Montreal Protocol, researchers had to account for long- and short-term natural fluctuations in ozone concentration, Cunnold noted. One such fluctuation is an 11-year solar cycle, and another is a two-year oscillation that occurs in the tropics, but affects ozone in other latitudes because of atmospheric transport. Despite the natural fluctuations, Yang, Cunnold and their co-authors are very confident in the conclusions they reached from the data they analyzed.“We know from the study we’ve just published that the Montreal Protocol -- the first major global agreement related to atmospheric change -- is working,” Cunnold said.A new NASA satellite called Aura is continuing to measure ozone in various regions of the stratosphere, and these same researchers are involved in the ongoing study of the ozone layer using the satellite’s data.

Ozone Holes

August 29, 2006

https://www.sciencedaily.com/releases/2006/08/060829080436.htm

Dogs And Smog Don't Mix: Pets In Homes May Lead To Increased Rates Of Bronchitis In Children

A new study from researchers at the Keck School of Medicine of the University of Southern California (USC) suggests that having a dog in the home may worsen the response to air pollution of a child with asthma. The study was published this week in the online edition of Environmental Health Perspectives, the journal of the National Institute of Environmental Health Sciences.

In "Dog Ownership Enhances Symptomatic Responses to Air Pollution in Children with Asthma," researchers looked at the relationship between chronic cough, phlegm production or bronchitis and dog and cat ownership among 475 southern California children with asthma who participated in the Children's Health Study, a longitudinal study of air pollution and respiratory health. Children with dogs had significantly increased cough, phlegm production and bronchitis responses to the measured pollutants, including nitrogen dioxide, ozone, particulate matter and acid vapor. There were no increases of these symptoms in children who lived in homes without pets or who lived with only cats."Further work is needed to determine what it is about dogs that may increase an asthmatic child's response to air pollution," says Rob McConnell, M.D., professor of preventive medicine at the Keck School of Medicine of USC and lead author of the study.McConnell and colleagues speculated that the increased response to air pollution from a dog in the home may really be due to increased levels of endotoxin, which is more common in homes where there is a dog. "Cats are highly allergenic, and children with asthma are often allergic to cats," says McConnell. "Therefore if an allergen were enhancing the lung's response to air pollution, we'd be more likely to see an association with cats. But in this study we see an effect of air pollution in homes with dogs, so we think endotoxin exposure is a more likely explanation for our results than allergen exposure."Endotoxin is a part of the cell wall of common bacteria in the environment. The authors note that inhaled endotoxin produces a marked inflammatory response in the lungs, and it may cause the airways of people with asthma to constrict. In previous studies, endotoxin has been shown to enhance the inflammatory effect of diesel exhaust particulate, inhaled highway aerosols and ozone in the lungs of experimental animals."There's experimental literature that shows both allergens and endotoxin interact with air pollution and increase the effect of each other," says McConnell. "But there's been very little study to see if these experiments have relevance for the general population of children with asthma."McConnell cautioned that much more study is needed to specify why, exactly, children with asthma living in homes with dogs had an enhanced response to air pollution. "There are other possible explanations for the findings," he says, "and actual measurements of home allergen and endotoxin, in addition to air pollution, would be important to evaluate further our hypothesis. It could also be that something only indirectly related to dogs could explain these results, for example that kids with dogs exercise outside more so they have more exposure to air pollution."The research was supported by the National Institute of Environmental Health Sciences, the Southern California Particle Center, the U.S. Environmental Protection Agency, the National Heart Lung and Blood Institute, the California Air Resources Board and the Hastings Foundation. Rob McConnell, Kiros Berhane, Jassy Molitor, Frank Gilliland, Nino Kunzli, Peter S. Thorne, Duncan Thomas, W. James Gauderman, Edward Avol, Fred Lurmann, Edward Rappaport, Michael Jerrett, John M. Peters, "Dog Ownership Enhances Symptomatic Responses to Air Pollution in Children with Asthma," Environmental Health Perspectives, online Aug. 29, 2006.

Ozone Holes

August 24, 2006

https://www.sciencedaily.com/releases/2006/08/060823185200.htm

Sulfur Signature Changes Thoughts On Atmospheric Oxygen

Ancient sediments that once resided on a lake bed and the ocean floor show sulfur isotope ratios unlike those found in other samples from the same time, calling into question accepted ideas about when the Earth's atmosphere began to contain oxygen, according to researchers from the U.S., Canada and Japan.

"The popular model is that there was little oxygen in the Earth's atmosphere before about 2.4 billion years ago," says Dr. Hiroshi Ohmoto, professor of geochemistry and director, Penn State Astrobiology Research Center. "Scientists use the ratio of the various sulfur isotopes as their strongest evidence for atmospheric oxygen." All isotopes of sulfur behave the same chemically but have slightly different masses. Sulfur has four isotopes. About six years ago, researchers began measuring the abundance of these isotopes and determined their ratios in the natural world. These ratios are called mass dependent isotope fractionation and are the way sulfur fractionates today. But rocks dating before 2.4 billion years ago have abnormal ratios, or exhibit mass independent fractionation. Generally, scientists attributed this abnormal fractionation to atmospheric chemical reactions. The reaction thought to occur before 2.4 billion years ago is that sulfur dioxide produced by volcanos is separated into native sulfur and sulfuric acids by ultra violet light. Because ozone forms an ultra violet impenetrable shield around the Earth, this reaction could not occur if ozone existed. Ozone is a common component of our atmosphere and is composed of three atoms of oxygen. If the atmosphere has no ozone, it is assumed the atmosphere has no oxygen. Ohmoto, working with Dr. Yumiko Watanabe, research associate, Penn State; Dr. Hiroaki Ikemi, former Penn State post doctoral fellow; and Dr. Simon R. Poulson, former Penn State doctoral student now a professor at University of Nevada, and Dr. Bruce E. Taylor, Geological Survey of Canada, report in today's (Aug. 24) issue of Nature the isotopic, mineralogical and geochemical results of drilling cores recovered by the Archaean Biosphere Drilling Project in the Pilbara Craton, Pilbara, Australia. ABDP is an international project funded largely by the NASA Astrobiology Institute, the Japanese Ministry of Education and Science and the Geological Survey of Western Australia. The two core segments represent one of the oldest lake sediments -- 2.76 billion years old -- and one of the oldest marine shale sediments -- 2.92 billion years old. Surprisingly, both samples' sulfur isotope ratios fall in the mass-dependent fractionation range and do not show the signal of an oxygenless atmosphere. "We analyzed the sulfur composition and could not find the abnormal sulfur isotope ratio," said Ohmoto. "This is the first time that sediment that old was found to contain no abnormal sulfur isotope ratio." One possible explanation is that perhaps oxygen levels during that time period fluctuated greatly creating a "yo yo" atmosphere: Going from oxygenless before 3 billion years ago to oxygenated between 3 billion and 2.75 billion years ago and then back to oxygenless from 2.75 billion to 2.4 billion years ago. The researchers suggest that future investigation of different geologic formation could indicate that oxygen fluctuation was even more frequent. Another explanation could be that the atmosphere contained oxygen as early as 3.8 billion years ago and that mass independent isotope ratios of sulfur occurred because of violent volcanic eruptions and enormous amounts of sulfur dioxide released into the atmosphere. Investigation of ash sediments from recent Mt. Pinatubo eruptions and other major volcanic events show a signature of mass independent isotope ratios of sulfur, while sediment from minor eruption does not. The photochemical reaction of volcanic sulfur dioxide may not be the only method of creating a mass independent fractionation of sulfur. Reactions between sulfate-rich seawater and organic material in the sediment during the formation of sedimentary rock layers might produce sulfur with mass independent fractionation. If so, the commonly believed linkage between the abnormal sulfur isotope ratios in sediments and an oxygen-free atmosphere must be reevaluated.

Ozone Holes

August 24, 2006

https://www.sciencedaily.com/releases/2006/08/060822181918.htm

Just Breathe: Ozone Forecaster Unveiled, Available Via Web

People with asthma or other respiratory problems can breathe a sigh of relief thanks to University of Houston professors who have recently unveiled a forecasting system that provides air quality data on ozone conditions.

With the intent to not only increase public awareness, but also help Texas manage air quality issues, the Institute for Multi-dimensional Air Quality Studies (IMAQS) at UH has been operating an air quality forecasting system for a year that has been tested, fine-tuned and now determined ready for public use. Over the course of this past year, the system has been expanded and improved to serve the entire eastern half of Texas, including the Houston and Dallas metropolitan areas. "Our ozone forecaster is more localized than others and goes into further detail," said Daewon Byun, director of IMAQS and a professor in UH's geosciences department. "For instance, while the ozone conditions may be rated unhealthy in downtown Houston on a given day, suburbs like Sugar Land and The Woodlands may actually be experiencing a good day that still is safe for outdoor activities in those specific areas. Other days, the opposite is true with downtown-area ozone levels being lower than in certain suburbs." By clicking on the local, regional or national maps at Byun stresses that while the traditional ozone season lasts from June through September, Houston suffers the consequences all year long. In a related project, UH's IMAQS is collaborating with Winifred Hamilton, director of the Baylor College of Medicine's Environmental Health Section, who is using Byun's air quality data in the patient-care arena and in her work to increase public awareness of the connection between health and the environment. Accurate meteorological and photochemical modeling efforts are essential to support the efforts for establishing the State Implementation Plan by the Texas Commission on Environmental Quality (TCEQ), Byun said. Houston currently is in severe noncompliance, experiencing more than 30 days per year of high ozone conditions. The EPA's ozone standard allows just one day per year of such conditions, and the Houston-Galveston-Brazoria area must meet these existing standards by 2007 or risk losing highway funding, among other penalties. "The air quality forecasting is made by the photochemical air quality models that take data on both manmade and biogenic emission values and meteorological inputs, coupled with descriptions of the physical and chemical processes that occur in the atmosphere," Byun said. "We then mathematically and numerically process the information to yield predictions of air pollutant concentrations as a function of time and location." With funding from the EPA, TCEQ, Texas Environmental Research Consortium and Houston Advanced Research Center, Byun has collaborated with researchers at UH from the fields of geosciences, mathematics, computer science and chemistry on a number of projects to build this ozone forecasting system. The TCEQ also provides key emissions input and technical assistance for the project. Past IMAQS initiatives leading up to the success and unveiling of this air quality tool include: "Improving Houston's air quality cannot begin without the level of detail that Byun and his colleagues have put into this research," said Jack Casey, chair of UH's geosciences department in the College of Natural Sciences and Mathematics. "Developing the ozone forecasting system and its continuous verification and improvement with the help of regional chemical measurement programs is an important first step in understanding Houston's air quality problem. Because of the smaller local grid spacing, the Web site is better than any other state or national forecasting Web site for ozone alerts in this region. With the release of these forecasts on a daily basis, Byun and IMAQS are performing an important service for the Houston and southeastern Texas community."

Ozone Holes

August 21, 2006

https://www.sciencedaily.com/releases/2006/08/060821134849.htm

Scientists First To Predict Air Quality Impact Of Small-scale Power Sources

As California searches for more sources of power, researchers at UC Irvine have created the first scientific method for predicting the impact of small-scale generators on air quality – a tool that could help the state develop environmentally sound policies to regulate and promote their use.

Using a supercomputer, scientists analyzed thousands of variables including land-use information, emissions data and atmospheric chemistry to determine the potential effect of distributed generation on Southern California air by 2010. Distributed generation – the operation of many small stationary power generators located throughout an urban air basin – includes fuel cells, photovoltaics, gas turbines, micro-turbine generators and natural gas internal combustion engines. The use of clean distributed generation in place of traditional power-plant generation cuts down on electricity transmission losses, reduces the need for unsightly overhead power lines and facilitates the use of generator waste heat, which further reduces electricity needs and emissions.Results showed that maximum levels of ozone and particulate matter could increase slightly in Southern California because of more distributed generation use, but the impact could be far less than other power-production alternatives, such as building more power plants inside the air basin. Officials throughout the United States are discussing the merits of using more distributed generation because existing plants are reaching capacity at a time when power demand is increasing nationwide.“Because of grid constraints, growing power demands and high power cost, California could become one of the first places where small-scale power production methods become widespread,” said Donald Dabdub, a professor of mechanical and environmental engineering in The Henry Samueli School of Engineering. “Decision-makers will need a way to assess distributed generation’s impact on air quality, and our computer model and methodology are the first to address this need.”This study by Dabdub; Scott Samuelsen, director of the National Fuel Cell Research Center at UCI; and Jack Brouwer, associate director of the center, is the first to determine the potential air quality impact of distributed generation. Some results were published online in the September issue of Atmospheric Environment.The research team found that if distributed generation were used to meet up to 20 percent of the increased power demand in Southern California by 2010, the basin-wide peak ozone level would increase by no more than three parts per billion. In 2003, the maximum one-hour ozone level in the South Coast air basin was 194 parts per billion. Ozone can harm the upper respiratory tract, causing a cough, shortness of breath and nausea.The peak concentration of particulate matter – small specks of chemicals and soot that can lodge in the lungs and cause health problems – would increase by no more than two micrograms per cubic meter. In 2003, the peak daily particulate matter concentration in the South Coast air basin was 121 micrograms per cubic meter.Despite the potential increases, researchers say that appropriate use of distributed generation is better for the air than other methods of generating additional power such as building more nuclear, coal-fired or natural gas power plants. The popularity of distributed generation is growing – today, more than 2,000 megawatts of distributed generation facilities have been installed in California, and officials expect the addition of up to 400 megawatts in small-scale projects each year. About 60 gigawatts of installed capacity currently exist in California.“The use of distributed generation in Southern California is preferable to other in-basin strategies that we may be forced to adopt to meet the power demand in the future,” Brouwer said. “Even the cleanest natural gas power plant will have a larger air quality impact than fuel cell distributed generation. This small-scale technology has the potential to fulfill the energy needs of many consumers and provide overall energy efficiency and cost savings.”Scientists used their computer model and research technique to determine when, where and how distributed generation could be used to produce the best possible air quality impact. They found that it is best to operate small-scale technologies as evenly as possible with regard to time, avoiding short bursts of operation. Distributed generation should be installed equally throughout the air basin, not concentrated in any one area, and the cleanest generation technologies such as fuel cell and photovoltaic devices should be used. These two technologies were found to have zero impact on ozone and particulate matter in the atmosphere – even though fuel cell systems do produce emissions.A fuel cell works by converting the chemical energy of a fuel, such as natural gas, and an oxidant, such as air, directly to electricity using electro-chemistry. Solar photovoltaic devices use semiconducting materials to convert sunlight directly to electricity.If fuel cells alone were used in place of a mixture of distributed generation technology investigated by the research team, they could lead to a reduction of up to three parts per billion in peak ozone and up to two micrograms per cubic meter of peak particulate matter, researchers said. Their findings suggest that fuel cell distributed generation could reduce future peak ozone concentrations by as much as six parts per billion and peak particulate matter by up to three micrograms per cubic meter compared to current power plant technology.This project was funded by the California Energy Commission under the Public Interest Energy Research program.

Ozone Holes

July 31, 2006

https://www.sciencedaily.com/releases/2006/07/060731165637.htm

Food-crop Yields In Future Greenhouse-gas Conditions Lower Than Expected

Open-air field trials involving five major food crops grown under carbon-dioxide levels projected for the future are harvesting dramatically less bounty than those raised in earlier greenhouse and other enclosed test conditions -- and scientists warn that global food supplies could be at risk without changes in production strategies.

The new findings are based on on-going open-air research at the University of Illinois at Urbana-Champaign and results gleaned from five other temperate-climate locations around the world. According to the analysis, published in the June 30 issue of the journal Science, crop yields are running at about 50 percent below conclusions drawn previously from enclosed test conditions. Results from the open-field experiments, using Free-Air Concentration Enrichment (FACE) technology, "indicate a much smaller CO2 fertilization effect on yield than currently assumed for C3 crops, such as rice, wheat and soybeans, and possibly little or no stimulation for C4 crops that include maize and sorghum," said Stephen P. Long, a U. of I. plant biologist and crop scientist. FACE technology, such as the SoyFACE project at Illinois, allows researchers to grow crops in open-air fields, with elevated levels of carbon dioxide simulating the composition of the atmosphere projected for the year 2050. SoyFACE has added a unique element by introducing surface-level ozone, which also is rising. Ozone is toxic to plants. SoyFACE is the first facility in the world to test both the effects of future ozone and CO2 levels on crops in the open air. Older, closed-condition studies occurred in greenhouses, controlled environmental chambers and transparent field chambers, in which carbon dioxide or ozone were easily retained and controlled. Such tests provided projections for maize, rice, sorghum, soybean and wheat -- the world's most important crops in terms of global grain production. By 2050 carbon dioxide levels may be about 1.5 times greater than the current 380 parts per million, while daytime ozone levels during the growing season could peak on average at 80 parts per billion (now 60 parts per billion). Older studies, as reviewed by the Intergovernmental Panel on Climate Change, suggest that increased soil temperature and decreased soil moisture, which would reduce crop yields, likely will be offset in C3 crops by the fertilization effect of rising CO2, primarily because CO2 increases photosynthesis and decreases crop water use. Although more than 340 independent chamber studies have been analyzed to project yields under rising CO2 levels, most plants grown in enclosures can differ greatly from those grown in farm fields, Long said. FACE has been the only technology that has tested effects in real-world situations, and, to date, for each crop tested yields have been "well below (about half) the value predicted from chambers," the authors reported. The results encompassed grain yield, total biomass and effects on photosynthesis. The FACE data came from experimental wheat and sorghum fields at Maricopa, Ariz.; grasslands at Eschikon, Switzerland; managed pasture at Bulls, New Zealand; rice at Shizukuishi, Japan; and soybean and corn crops at Illinois. In three key production measures, involving four crops, the authors wrote, just one of 12 factors scrutinized is not lower than chamber equivalents, Long said. "The FACE experiments clearly show that much lower CO2 fertilization factors should be used in model projections of future yields," the researchers said. They also called for research to examine simultaneous changes in CO2, O3, temperature and soil moisture." While projections to 2050 may be too far out for commercial considerations, they added, "it must not be seen as too far in the future for public sector research and development, given the long lead times that may be needed to avoid global food shortage."Long and four colleagues were co-authors: Elizabeth A. Ainsworth, professor of plant biology; Andrew D.B. Leakey, research fellow in the Institute of Genomic Biology at Illinois; Donald R. Ort, professor of plant biology and crops sciences; and Josef Nösberger, professor at the Swiss Federal Institute of Science and Technology in Zurich. Long, Ainsworth and Ort also are affiliated with the Institute for Genomic Biology, and Ainsworth and Ort also are scientists in the USDA-ARS Photosynthesis Research Unit on the Illinois campus. The Illinois Council for Food and Agricultural Research, Archer Daniels Midland Co., the USDA and U. of I. Experiment Station funded the research.

Ozone Holes

June 30, 2006

https://www.sciencedaily.com/releases/2006/06/060630095235.htm

Scientists Find Antarctic Ozone Hole To Recover Later Than Expected

The Antarctic ozone hole's recovery is running late. According to a new NASA study, the full return of the protective ozone over the South Pole will take nearly 20 years longer than scientists previously expected.

Scientists from NASA, the National Oceanic and Atmospheric Administration and the National Center for Atmospheric Research in Boulder, Colo., have developed a new tool, a math-based computer model, to better predict when the ozone hole will recover.The Antarctic ozone hole is a massive loss of ozone high in the atmosphere (the stratosphere) that occurs each spring in the Southern Hemisphere. The ozone hole is caused by chlorine and bromine gases in the stratosphere that destroy ozone. These gases come from human-produced chemicals such as chlorofluorocarbons, otherwise called CFCs.The ozone layer blocks 90-99 percent of the sun's ultraviolet radiation from making contact with Earth. That harmful radiation can cause skin cancer, genetic damage, and eye damage, and harm marine life.For the first time, a model combines estimates of future Antarctic chlorine and bromine levels based on current amounts as captured from NASA satellite observations, NOAA ground-level observations, NCAR airplane-based observations, with likely future emissions, the time it takes for the transport of those emissions into the Antarctic stratosphere, and assessments of future weather patterns over Antarctica.The model accurately reproduces the ozone hole area in the Antarctic stratosphere over the past 27 years. Using the model, the researchers predict that the ozone hole will recover in 2068, not in 2050 as currently believed."The Antarctic ozone hole is the poster child of ozone loss in our atmosphere," said author Paul Newman, a research scientist at NASA's Goddard Space Flight Center, Greenbelt, Md. And lead author of the study. "Over areas that are farther from the poles like Africa or the U.S., the levels of ozone are only three to six percent below natural levels. Over Antarctica, ozone levels are 70 percent lower in the spring. This new method allows us to more accurately estimate ozone-depleting gases over Antarctica, and how they will decrease over time, reducing the ozone hole area."International agreements like the Montreal Protocol have banned the production of most chemicals that destroy ozone. But the researchers show that the ozone hole has not started to shrink a lot as a result. The scientists predict the ozone hole will not start shrinking a lot until 2018. By that year, the ozone hole's recovery will make better time.

Ozone Holes

June 14, 2006

https://www.sciencedaily.com/releases/2006/06/060614120803.htm

UT Southwestern Allergist Offers Coping Strategies For Relief From Summer Allergens

The good news for allergy sufferers is that springtime mountain cedars and tree pollens have generally subsided.

The bad news: It's summertime."For summer, it will be grass pollen along with high ozone levels combining for a one-two punch," said Dr. David Khan, associate professor of internal medicine at UT Southwestern Medical Center. "In July, cedar elm will appear."While heat doesn't influence the amount of pollen in the air, it does aid in the formation of ground-level ozone, which, in turn, can exacerbate allergy symptoms.To cope, Dr. Khan, who also directs the asthma clinic at Parkland Memorial Hospital, offers these tips: * Limit outdoor exposure during peak times — from mid-morning to midday.Choosing the right medications to help control symptoms is important, Dr. Khan said. Antihistamines are the most common medications used for allergies. They can help relieve itching, sneezing and runny noses, but don't generally help with stuffiness. Oral decongestants like pseudoephedrine generally work for stuffy noses.Topical decongestants — nose sprays — aren't a good long-term solution because you can become addicted to them, causing nasal passages to swell even more and possibly resulting in other nasal problems as well.If symptoms aren't subdued or allergies are interfering with your lifestyle or work, it's probably a good time to find an allergy specialist and see if other treatments may help."It's reasonable to try some of the over-the-counter drugs first, and if you're not satisfied with those results, then you need to see a doctor," Dr. Khan said.At UT Southwestern, patients can be evaluated by UT Southwestern allergists in clinics at the James W. Aston Ambulatory Care Center, Parkland Memorial Hospital and Children's Medical Center Dallas, where doctors treat airborne and environmental allergies or asthma, food and drug allergies, and conditions like hives and allergic reactions.Prescription antihistamines can offer more potency and be less sedating than over-the-counter measures, Dr. Khan said.Corticosteroid anti-inflammatory nasal sprays can be used regularly, often once a day, and are generally safe and effective. These are not the same as anabolic steroids that athletes sometimes abuse and for which some school systems now test.Antihistamines, decongestants and corticosteroids, however, do no more than depress symptoms. "Although you'll be reducing the effect of the allergic reaction, you'll still be just as allergic at the end of the day," Dr. Khan said.Shots are the most effective medical treatment, he said, actually making allergy sufferers less allergic.There's also a novel clinical approach, called rush immunotherapy, which simply means taking more shots over a shorter period of time. Doctors think this may help expedite results.For more information or to schedule an appointment in the UT Southwestern allergy and immunology clinic for a patient 6 and older, please call 214-648-3678.

Ozone Holes

June 14, 2006

https://www.sciencedaily.com/releases/2006/06/060614000908.htm

Scientists Find Chlorine May Contribute To Ozone Formation

Standard methods of predicting air pollution don’t take atmospheric chlorine into account, but the chemical could be responsible for 10 percent or more of daily ozone production in local air, research at UC Irvine has found.

Air measurements taken nearly nonstop in the Irvine area over a two-month period showed that daytime chlorine gas levels typically measured five parts per trillion or less, but occasionally reached as high as 15 parts per trillion. Observation of daytime chlorine is surprising because chlorine molecules break apart just minutes after entering the atmosphere and being exposed to sunlight.With these measurements, scientists estimate that chlorine photochemistry creates five to eight parts per billion of the maximum daily ozone level, which in California typically ranges between 40 and 80 parts per billion.“Chlorine chemistry can have a direct impact on surface ozone even at parts per trillion levels,” said Eric Saltzman, professor of Earth system science in the School of Physical Sciences at UCI. “Because of the strong link between ozone and human health, we need to fully understand the role chlorine may play in ozone chemistry in coastal urban environments.” Saltzman and Brandon Finley, a graduate student researcher in the Department of Earth System Science, published their findings in the current issue of Geophysical Research Letters.Chlorine salts are naturally present in coastal air in sea salt aerosols, which are swept from the ocean into the air by the wind. Chlorine gas also is used to treat water in swimming pools, cooling towers and municipal water supplies. Chlorine atoms react rapidly with hydrocarbons and nitrogen oxides from automobile and power plant emissions, contributing to the complex chain of reactions that leads to ozone formation. The primary cause of urban ozone is the reaction of hydroxyl radical (OH) with hydrocarbons and nitrogen oxides. OH is a highly reactive molecule made of oxygen and hydrogen that forms photochemically in air. “For the last 30 years, we’ve known that the hydroxyl radical is the primary cause of ozone,” Saltzman said. “Chlorine plays a similar role. It doesn’t take much chlorine to affect ozone chemistry.”This study is the first to extensively measure atmospheric chlorine in Southern California air over several consecutive weeks. Researchers made extremely sensitive chlorine measurements, detecting the chemical at levels as low as three parts per trillion.Results showed that chlorine is present in the atmosphere both day and night, and that its levels fluctuate with little regularity. Saltzman and Finley couldn’t pinpoint the cause of these changes, finding no obvious link between chlorine levels and meteorological conditions such as wind, temperature or relative humidity or existing pollution levels. They also don’t know for sure what created the chlorine they detected.“We found more chlorine in the daytime than expected. It must be rapidly produced, because sunlight destroys it so quickly,” Saltzman said. “Most likely the process involves airborne marine particles, but research is needed to understand how it occurs.”Inland ozone levels typically are higher than on the coast, mainly because of meteorological conditions that restrict air circulation and trap pollutants. Ozone is a highly reactive and unstable gas that damages living cells. Even low levels of ozone can harm the upper respiratory tract and the lungs, causing a cough, throat irritation and reduced lung function, and aggravating the effects of asthma, bronchitis and emphysema.Said Saltzman, “Understanding the chemistry of chlorine is important to understanding its role in ozone chemistry, especially in California where air quality is such an important issue.”

Ozone Holes

May 27, 2006

https://www.sciencedaily.com/releases/2006/05/060527093645.htm

Earth's Ozone Layer Appears To Be On The Road To Recovery

Think of the ozone layer as Earth's sunglasses, protecting life on the surface from the harmful glare of the sun's strongest ultraviolet rays, which can cause skin cancer and other maladies.

People were understandably alarmed, then, in the 1980s when scientists noticed that manmade chemicals in the atmosphere were destroying this layer. Governments quickly enacted an international treaty, called the Montreal Protocol, to ban ozone-destroying gases such as CFCs then found in aerosol cans and air conditioners.Today, almost 20 years later, reports continue of large ozone holes opening over Antarctica, allowing dangerous UV rays through to Earth's surface. Indeed, the 2005 ozone hole was one of the biggest ever, spanning 24 million sq km in area, nearly the size of North America.Listening to this news, you might suppose that little progress has been made. You'd be wrong.While the ozone hole over Antarctica continues to open wide, the ozone layer around the rest of the planet seems to be on the mend. For the last 9 years, worldwide ozone has remained roughly constant, halting the decline first noticed in the 1980s.The question is why? Is the Montreal Protocol responsible? Or is some other process at work?It's a complicated question. CFCs are not the only things that can influence the ozone layer; sunspots, volcanoes and weather also play a role. Ultraviolet rays from sunspots boost the ozone layer, while sulfurous gases emitted by some volcanoes can weaken it. Cold air in the stratosphere can either weaken or boost the ozone layer, depending on altitude and latitude. These processes and others are laid out in a review just published in the May 4th issue of Nature: "The search for signs of recovery of the ozone layer" by Elizabeth Westhead and Signe Andersen.Sorting out cause and effect is difficult, but a group of NASA and university researchers may have made some headway. Their new study, entitled "Attribution of recovery in lower-stratospheric ozone," was just accepted for publication in the Journal of Geophysical Research. It concludes that about half of the recent trend is due to CFC reductions.Lead author Eun-Su Yang of the Georgia Institute of Technology explains: "We measured ozone concentrations at different altitudes using satellites, balloons and instruments on the ground. Then we compared our measurements with computer predictions of ozone recovery, [calculated from real, measured reductions in CFCs]." Their calculations took into account the known behavior of the sunspot cycle (which peaked in 2001), seasonal changes in the ozone layer, and Quasi-Biennial Oscillations, a type of stratospheric wind pattern known to affect ozone.What they found is both good news and a puzzle.The good news: In the upper stratosphere (above roughly 18 km), ozone recovery can be explained almost entirely by CFC reductions. "Up there, the Montreal Protocol seems to be working," says co-author Mike Newchurch of the Global Hydrology and Climate Center in Huntsville, Alabama.The puzzle: In the lower stratosphere (between 10 and 18 km) ozone has recovered even better than changes in CFCs alone would predict. Something else must be affecting the trend at these lower altitudes.The "something else" could be atmospheric wind patterns. "Winds carry ozone from the equator where it is made to higher latitudes where it is destroyed. Changing wind patterns affect the balance of ozone and could be boosting the recovery below 18 km," says Newchurch. This explanation seems to offer the best fit to the computer model of Yang et al. The jury is still out, however; other sources of natural or manmade variability may yet prove to be the cause of the lower-stratosphere's bonus ozone.Whatever the explanation, if the trend continues, the global ozone layer should be restored to 1980 levels sometime between 2030 and 2070. By then even the Antarctic ozone hole might close--for good.

Ozone Holes

May 24, 2006

https://www.sciencedaily.com/releases/2006/05/060524123900.htm

Many Cleaners, Air Fresheners May Pose Health Risks When Used Indoors

When used indoors under certain conditions, many common household cleaners and air fresheners emit toxic pollutants at levels that may lead to health risks, according to a new study by researchers at the University of California, Berkeley, and Lawrence Berkeley National Laboratory.

Exposure levels to some of the pollutants - and to the secondary pollutants formed when some of the products mix with ozone - may exceed regulatory guidelines when a large surface is cleaned in a small room or when the products are used regularly, resulting in chronic exposure, according to the study.The study is the first to measure emissions and concentrations of primary and secondary toxic compounds produced by these products under typical indoor use conditions, and it examines the potential hazards of small-scale yet widespread utilization of an array of products designed for household use."We've focused a lot of effort in the last decades on controlling the big sources of air pollution and on the chemicals in consumer products that contribute to outdoor ozone formation. However, now we've learned that we need to pay attention to other aspects of pollution sources that are right under our nose," said William Nazaroff, a UC Berkeley professor of environmental engineering and the study's lead author.To comply with its mandate to protect public health and welfare, for the past four decades the California Air Resources Board (ARB) has been developing and implementing regulatory programs to reduce air pollution in the state. These regulations also cover emissions of volatile organic compounds from consumer products used in homes and institutions.Several years ago, when a handful of new studies raised the concern that consumer products may be contributing to indoor pollution levels in ways that were not fully understood, the ARB commissioned Nazaroff and his team to study the problem.Four years in the making, the team's 330-page study and report, "Indoor Air Chemistry: Cleaning Agents, Ozone and Toxic Air Contaminants," was posted online by the ARB on Wednesday, May 10.The ARB asked Nazaroff and his team to focus their work in two areas: an investigation of toxic air contaminants in household cleaning products and air fresheners, especially a class of chemicals known as ethylene-based glycol ethers; and an examination of the chemistry that occurs when such products are used indoors - in particular, products that contain a reactive group of chemicals called terpenes.Ethylene-based glycol ethers are common, water-soluble solvents used in a variety of cleaning agents, latex paints and other products. They are classified as hazardous air pollutants under the U.S. Environmental Protection Agency's 1990 Clean Air Act Amendments and as toxic air contaminants by California's Air Resources Board. Their toxicity varies with their chemical structure.Terpenes are a class of chemicals found in pine, lemon and orange oils that are used in many consumer products either as solvents or to provide a distinctive scent. Although terpenes themselves are not considered toxic, some recent studies have shown that they may react with ozone to produce a number of toxic compounds. (The primary constituent of smog, ozone enters the indoor environment from infiltration of outdoor air, but is also produced indoors by some office machines such as copiers or printers, and by some devices marketed as "air purifiers" that purposely emit ozone into the indoor environment.)The research team's first task was to determine which household products contain terpenes and glycol ethers, and in what quantities. It compiled a list of the household cleaners and air fresheners available at any of five chain retail outlets in Northern California, then examined the labels and advertising claims (e.g. "pine-scented") for these products and reviewed available product data sheets. Based on this information, they selected the 21 products most likely to contain significant amounts of terpenes and ethylene-based glycol ethers: four air fresheners and 17 cleaning products, including at least one each of disinfectants, general-purpose degreasers, general-purpose cleaners, wood cleaners, furniture maintenance products, spot removers and multi-purpose solvents.A complete chemical analysis of these 21 products revealed that:• Twelve contained terpenes and other ozone-reactive compounds at levels ranging from 0.2 to 26 percent by mass.• Six contained levels of ethylene-based glycol ethers of 0.8 to 9.6 percent by mass.• Among the four air fresheners studied, three contained substantial quantities of terpenes (9-14 percent by mass)When the researchers tested the terpene-containing products in the presence of ozone, they found that reactions produced very small particles with properties like those found in smog and haze; other oxidation products; and formaldehyde, a respiratory irritant that is classified as a Group 1 carcinogen. (This designation by the International Agency for Cancer Research is reserved for substances for which there is sufficient evidence to conclude that they cause cancer in humans.) The amounts of terpenes that were converted into these pollutants was dependent on the amount of ozone present.After completing their chemical analyses, the researchers ran a series of 18 experiments to determine the levels of exposure people might be subjected to when using the products in a confined space. The tests were conducted in a 230-square-foot room with ventilation at an ordinary level which provided approximately one air change every two hours. In some tests of terpene-containing products, ozone was introduced into the room at levels mimicking those that could occur in households or offices.The products were used in various ways according to package directions: some at full-strength and others at various dilutions as recommended on their labels. In some tests, used cleaning supplies such as paper towels and sponges were left in the room. In others, supplies were promptly removed.The tests produced various results - some reassuring, and some raising concerns.The good news, the researchers reported, is that when people use the products under ordinary circumstances, their exposure to ethylene-based glycol ethers, formaldehyde and fine particles will normally not reach guideline values: that is, levels set by regulatory agencies as the maximum exposure levels believed to be safe. However, the authors pointed out, because formaldehyde is also released from other sources such as plywood and pressed wood products that are found in most buildings, any increase in formaldehyde emissions is undesirable.In several realistic use scenarios, the tests showed that people could be exposed to potentially dangerous levels of toxic pollutants. The scenarios included:• Cleaning in a small, moderately ventilated bathroom. In calculations based on emissions from one of the glycol-ether containing products, the team found that a person who spends 15 minutes cleaning scale off of a shower stall could inhale three times the "acute one-hour exposure limit" for this compound set by the California Office of Environmental Health Hazard Assessment.• Air freshener and ozone in a child's bedroom. This scenario could occur when people use both air fresheners and ozone-generating devices simultaneously in a room. This could lead to exposures to formaldehyde that are 25 percent higher than California's guideline value. Because other sources of formaldehyde could also be present in the room, exposure to formaldehyde would probably be even higher, the report states.• Cleaning when outdoor ozone levels are high. This scenario simulates an apartment in Southern California on a day when the mid-afternoon outdoor ozone concentration is high. A person who stays in the kitchen for two hours after using a moderate amount of one of the terpene-containing products would breathe in about one quarter of the total daily guideline value for particulate matter.• Multi-house cleaning by a professional home cleaner. Under this scenario, a person who cleans four houses a day, five days per week, 50 weeks per year, would take in about 80 micrograms per day of formaldehyde, double the guideline value set by California's Proposition 65. In addition, the person's intake of fine particulate matter during the hours spent cleaning would exceed the average federal guideline level for an entire year. These quantities are in addition to the formaldehyde and particulate matter that the person would be exposed to from all other sources and activities during the year.The take-home message from these studies, according to Nazaroff, is that everyone - but especially cleaning professionals - should be cautious about overuse of products with high levels of ethylene-based glycol ethers and terpenes. Rooms should be ventilated during and after cleaning, some products should be used in diluted solutions as opposed to full-strength, and cleaning supplies should be promptly removed from occupied spaces once cleaning is done. Also, people should avoid the use of ozone generators or ionizing air cleaners, especially in the same space where terpene-containing cleaning products or air fresheners are being used.The report is an important milestone that highlights the need to investigate potential health effects of ultrafine particles produced in such reactions, said Bart Croes, chief of the ARB's Research Division."Dr. Nazaroff and his team have done a very thorough scientific assessment of the emissions from cleaning products and how they contribute to exposures of the users," Croes said. "Their results indicate that we need to look beyond the directly emitted compounds."The study cost $446,865, an amount wholly funded by the ARB.The report's other authors are Beverly K. Coleman, a UC Berkeley Ph.D. student with Nazaroff; Hugo Destaillats, Alfred T. Hodgson, Melissa M. Lunden and Brett C. Singer, all at Lawrence Berkeley National Laboratory; DeLing Liu, who was at UC Berkeley when she conducted the work but is now with the Jet Propulsion Laboratory in Pasadena, Calif.; and Charles J. Weschler, at the University of Medicine and Dentistry of New Jersey and the Technical University of Denmark.

Ozone Holes

May 12, 2006

https://www.sciencedaily.com/releases/2006/05/060512101931.htm

Record Air Pollution Above The Arctic

Scientists of the Alfred Wegener Institute for Polar and Marine Research have observed the highest air pollution on record since measurements began in Ny-Ålesund on Svalbard. Monitoring instruments displayed significantly increased aerosol concentrations compared to those generally found. Aerosols from eastern Europe have been transported into the Arctic atmosphere due to a particular large-scale weather situation.

High concentrations of aerosols and ozoneUsually the air is pure and clear above the French-German AWIPEV-Research base in Ny-Ålesund at the western coast of Svalbard. However, at the beginning of May it turned to a deep orange-brown. Confirming the observations of the German team, Swedish scientists of the Department of Applied Environmental Science at Stockholm University (ITM) measured up to fifty micrograms aerosol per cubic metre air in Ny-Ålesund. Such values are usually measured during rush hour in cities. In addition, the Norwegian Institute for Air Research (NILU) found extremely high concentrations of ozone above ground. With more than 160 micrograms ozone per cubic metre, these values are the highest measured since the foundation of the research base in 1989.Orange brown haze in the ArcticA specific weather condition has caused the record high air pollution. Large amounts of aerosols from eastern Europe were driven into the arctic atmosphere. Increased aerosol concentrations had already been measured at springtime of recent years. However, this "Arctic Haze" has never been as pronounced before.Aerosols constitute small particles in the atmosphere. They can be liquid or solid and serve as condensation nuclei during cloud formation. It is these properties that lead to aerosols influencing the climate system. "The present air pollution is more than 2.5 fold higher than values measured in spring 2000. As a consequence, we expect significantly increase warming ", explains Dr. Andreas Herber of the Alfred Wegener Institute in Bremerhaven.Scientists of the Alfred Wegener Institute have been measuring the aerosol content of the atmosphere above Svalbard since 1991. Measurements made via the institute’s aeroplanes serve the ongoing investigation of the impact of aerosols on the climate. “It is still difficult to estimate, whether this year’s data constitute the beginning of a common trend”, says Andreas Herber. “We need continued measurements in the course of subsequent years”. Moreover, the scientists expect the detailed examination of the origin and chemical composition of the aerosols to yield further understanding for the current observations.The AWIPEV research base in Ny-Ålesund is a joint station of the German Alfred Wegener Institute and the French Institut Polaire Paul Emile Victor (IPEV). It comprises the German Koldewey and the French Rabot research stations.

Ozone Holes

May 10, 2006

https://www.sciencedaily.com/releases/2006/05/060510094508.htm

International Treaty Designed To Restore, Protect Ozone Layer Working, Say Scientists

Countries world wide have controlled the production and use of ozone-eating chlorine compounds, and the Earth's atmosphere appears to be recovering from losses of "good" ozone in the upper reaches of the atmosphere. These findings were published in the journal Nature.

A paper by Betsy Weatherhead, a scientist working at the NOAA Earth System Research Laboratory in Boulder, Colo., and Signe Bech Andersen, of the Danish Meteorological Institute details an apparent leveling off of ozone loss as a result of the Montreal Protocol. This international agreement was first enacted in 1987 to control ozone-depleting chemicals in the atmosphere and was since signed by 180 countries."Ozone in the upper atmosphere protects life on Earth from harmful solar rays, and a thinning of ozone—even total depletion in some areas—has been a concern since the 1970s," said Weatherhead.Upper-atmosphere ozone is sometimes referred to as "good" ozone in contrast to "bad" ozone at the Earth's surface that is associated with smog and poor air quality.The paper is the first to show that the positive changes in the ozone layer are in general agreement with what is expected due to the changes in chlorine. Weatherhead said she and her colleagues are seeing signs of ozone recovery "in the right seasons, in the right latitudes and at the right altitudes." She called these positive signs a success story for international action to protect the environment. "Because the Montreal Protocol was enacted to control chlorine, the atmosphere is having a chance to recover," she said.Weatherhead indicated that ozone is constantly created, destroyed and transported in the atmosphere. As the pollutants filter out of the atmosphere, the ozone layer naturally rebuilds. Data from NOAA, NASA and a global monitoring network have shown that chlorine has leveled off in the atmosphere, and now clearly show that ozone loss is leveling off, too."In these early stages of recovery, it can often be difficult to say what causes long-term changes because the atmosphere is so complex," said Weatherhead. "To be confident that the ozone layer is recovering, we need more than just an increase in ozone. We need the changes to agree with observations of the other factors that can influence ozone levels."Weatherhead cautioned, however, that ozone remains at below-normal levels at all latitudes, and therefore, that ultra-violet (UV) rays from the sun are higher than they should be as well. People should continue to protect themselves from UV rays when they are outdoors.These first signs are hopeful, but the recovery process is still in early stages. Unusual temperatures or a large volcanic eruption could trigger more ozone loss."We may still see very low ozone levels in the next few years, but the general tendency we're observing is that the atmosphere is starting to heal," said Weatherhead.NOAA, an agency of the U.S. Department of Commerce, is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of the nation's coastal and marine resources.Through the emerging Global Earth Observation System of Systems (GEOSS), NOAA is working with its federal partners, 61 countries and the European Commission to develop a global network that is as integrated as the planet it observes, predicts and protects.

Ozone Holes

May 10, 2006

https://www.sciencedaily.com/releases/2006/05/060509235740.htm

Indoor Air Purifiers That Produce Even Small Amounts Of Ozone May Be Risky For Health

In a small, poorly ventilated room, an indoor air purifier that produces even a few milligrams of ozone per hour can create an ozone level that exceeds public health standards, researchers at UC Irvine have found.

Scientists also discovered that ozone produced by air purifiers adds to ozone already present in any room – a prediction that had never been experimentally verified in a realistic indoor environment.“These results mean that people operating air purifiers indoors are more prone to being exposed to ozone levels in excess of public health standards,” said Sergey A. Nizkorodov, assistant professor of chemistry in the School of Physical Sciences at UCI.Nizkorodov and UCI chemistry students Nicole Britigan and Ahmad Alshawa published their research in the current issue of the Journal of the Air & Waste Management Association. Their findings will be studied by officials deciding how to regulate the distribution of indoor air purifiers.California lawmakers are considering legislation that would require the California Air Resources Board to adopt regulations to reduce emissions from indoor air cleaners by 2008. The state board and the U.S. Environmental Protection Agency have issued advisories discouraging use of air purifiers, but the devices remain on the market because no agency has the outright authority to regulate how much ozone they produce.Indoor air purification has gained widespread popularity with the surge in air pollution problems in urban areas.Air purifiers target dust, pollen, airborne particles and volatile organic compounds, which are emitted by a wide range of products, including paint, cleaning supplies and pesticides. These pollutants are believed to aggravate respiratory and other health problems.Indoor air purifiers are advertised as safe household products for health-conscious people – especially those who suffer from allergies and asthma – but some purifiers produce ozone during operation. For example, certain widely used ionic air purifiers, which work by charging airborne particles and electrostatically attracting them to metal electrodes, emit ozone as a byproduct of ionization.Depending on the design, some ionic purifiers emit a few milligrams of ozone per hour, which is roughly equal to the amount emitted by a dry-process photocopier during continuous operation.Ozone can damage the lungs, causing chest pain, coughing, shortness of breath and throat irritation. It can also worsen chronic respiratory diseases such as asthma and compromise the ability of the body to fight respiratory infections – even in healthy people.For this study, the research group tested several types of air purifiers for their ability to produce ozone at 40 percent to 50 percent relative humidity in various indoor environments, including offices, bathrooms, bedrooms and cars.Placed inside a room, the air purifier was turned on, and the ozone concentration buildup was tracked until a steady level of ozone was reached. In many cases, indoor ozone levels far exceeded outdoor safety guidelines, which in California are 90 parts per billion for one hour and 70 parts per billion for eight hours.The ozone level in some instances reached higher than 350 parts per billion – more than enough to trigger a Stage 2 smog alert if similar levels were detected outside. A Stage 2 alert last occurred in the Southern California coastal air basin in 1988.Of the spaces tested, the largest increase in steady ozone levels occurred in small rooms with little ventilation, especially those containing materials that react slowly with ozone such as glossy ceramic tile, PVC tile and polyethylene, which is used in plastic. Ozone reacts quicker with materials such as carpet, cloth, rubber and certain metals, destroying itself in the process.People who operate purifiers indoors are more likely to be exposed to ozone levels that exceed health standards because ozone from these devices adds to ozone that already exists in the room.Said Nizkorodov: “If 30 parts per billion of ozone exist in the room because dirty outside air is leaking into the house, turning on an air purifier that generates 50 parts per billion of ozone creates a total ozone level of 80 parts per billion.”About AirUCI: Nizkorodov is a researcher with AirUCI – Atmospheric Integrated Research Using Chemistry at Interfaces – a multi-investigator effort led by chemistry professor Barbara Finlayson-Pitts to better understand how air and water interact in the atmosphere and how those processes affect air quality and global climate change. In 2004, UCI was awarded a total of $7.5 million over five years from the National Science Foundation to establish AirUCI, an Environmental Molecular Science Institute – one of only seven currently funded EMSIs dedicated to understanding at the molecular level how human activity and nature contribute to global environmental problems.

Ozone Holes

May 9, 2006

https://www.sciencedaily.com/releases/2006/05/060509174125.htm

Tibet Provides Passage For Chemicals To Reach The Stratosphere

NASA and university researchers have found that thunderstorms over Tibet provide a main pathway for water vapor and chemicals to travel from the lower atmosphere, where human activity directly affects atmospheric composition, into the stratosphere, where the protective ozone layer resides.

Learning how water vapor reaches the stratosphere can help improve climate prediction models. Similarly, understanding the pathways that ozone-depleting chemicals can take to reach the stratosphere is essential for understanding future threats to the ozone layer, which shields Earth from the sun's harmful ultraviolet rays.Researchers from the Georgia Institute of Technology, Atlanta; NASA’s Jet Propulsion Laboratory, Pasadena, Calif.; and the University of Edinburgh, Scotland, performed their analysis using data from the Microwave Limb Sounder instrument on NASA’s Aura spacecraft, combined with data from NASA’s Aqua and Tropical Rainfall Measuring Missions.The team collected more than 1,000 measurements of high concentrations of water vapor in the stratosphere over the Tibetan Plateau and the Asian monsoon region. The measurements were collected during August 2004 and August 2005, during the height of monsoon season. Through the use of wind data and NASA atmospheric models, they found the water vapor originated over Tibet, just north of the Himalayan mountain range.The team also found that even though more thunderstorms occurred over India, the storms over Tibet transported nearly three times more water vapor into the lower stratosphere than the more frequent thunderstorms that occur over India."This study shows that thunderstorms over Tibet are mainly responsible for the large amount of water vapor entering the stratosphere," said Dr. Rong Fu, associate professor in Georgia Tech's School of Earth and Atmospheric Sciences, who led the study. "The rainfall may not be as frequent over Tibet as over the Indian monsoon area, but because Tibet is at a much higher elevation than India, the storms over Tibet are strong and penetrate very high, and send water vapor right into the stratosphere."The study also found that the same pathway is responsible for transporting carbon monoxide, an indicator of air pollution, into the upper atmosphere."There's almost no carbon monoxide production in Tibet, so it's widely believed that carbon monoxide is transported to the tropopause over Southeast Asia and the Indian subcontinent,” Fu said. The tropopause divides the lower atmosphere from the stratosphere, and is located at an altitude of about 18 kilometers (11 miles) above Earth over the tropics and Tibet.Fu added, "Our study finds thunderstorms over Tibet transport as much carbon monoxide to the lower stratosphere as do those over India. When long-lived pollutants are transported out of the lower atmosphere, they can move rapidly. Pollutants from Asia, for example, can wind up on the other side of the world."The findings are published in the Proceedings of the National Academy of Sciences.Aura, Aqua and the Tropical Rainfall Measuring Mission are part of the NASA-centered international Earth Observing System, and are managed by NASA’s Goddard Space Flight Center, Greenbelt, Md. Aura’s Microwave Limb Sounder was built by JPL.For more information on the Microwave Limb Sounder and Aura, visit: For information on Aqua and the Tropical Rainfall Measuring Mission, visit: JPL is managed for NASA by the California Institute of Technology.

Ozone Holes

May 4, 2006

https://www.sciencedaily.com/releases/2006/05/060504070523.htm

Ozone Recovering, But Unlikely To Stabilize At Pre-1980 Levels, Says Study

While Earth's ozone layer is slowly being replenished following an international 1987 agreement banning CFCs, the recovery is occurring in a changing atmosphere and is unlikely to stabilize at pre-1980 levels, says a new University of Colorado at Boulder study.

The recovery is a result of the 1987 Montreal Protocol banning chlorine pollutants from the atmosphere, said Betsy Weatherhead, a researcher with the Cooperative Institute for Research in Environmental Sciences, a joint institute of CU-Boulder and the National Oceanic and Atmospheric Administration. But by the end of the century, ozone levels could be slightly higher or slightly lower than before 1980 because of high natural variability and human caused changes like warming temperatures, said Weatherhead. A paper by Weatherhead and Signe Bech Andersen of the Danish Meteorological Institute in Copenhagen is featured on the cover of the May 4 issue of Nature. "We now have some confidence that the ozone layer is responding to the decreases in chlorine levels in the atmosphere due to the leveling off and decrease of CFCs, and most of the improvements are in agreement with what we had hoped for with the Montreal Protocol in place," she said. "But we are not out of the woods yet, and the ozone recovery process still faces a number of uncertainties." At high latitudes, for example, warmer temperatures at Earth's surface can trigger colder conditions in the lower stratosphere and promote the formation of polar stratospheric clouds, which can contribute to severe ozone depletion. "During the next few years, ozone levels in the Arctic will be strongly influenced by stratospheric temperature, possibly resulting in delayed recovery or record-low observations," the authors wrote in Nature. The new study shows a larger than expected recovery of ozone in the northern mid-latitudes in recent years, she said. The increase may be partially a result of natural variability, including shifts in air temperatures and atmospheric transport, the influences of the 11-year solar cycle and an absence of major volcanic activity on Earth. The 1993 eruption of Mt. Pinatubo in the Philippines, for example, caused ozone levels to backslide for several years, Weatherhead said. Future ozone levels likely will be dominated by air temperature, atmospheric dynamics and an abundance of trace gases, she said. Trace gases include significant amounts of nitrous oxide, or N2O -- a result of fertilizer production on Earth -- and could lead to significant depletion of protective ozone molecules. "In another 50 years CFCs won't be the dominant factor controlling ozone," she said. "Instead, we think it will be factors like greenhouse gases, N2O and methane." The Nature study, which shows ozone levels have stabilized or increased slightly in the past 10 years, used data from satellites and ground stations to compare changes in the ozone layer to past depletion levels. The researchers used data from 14 modeling studies published by scientific groups from around the world for the study. The ozone data was collected by a suite of NASA and NOAA satellites and ground stations. The new study follows a 2005 study led by Weatherhead indicating the ozone layer was no longer in decline following nearly two decades of depletion from harmful chemicals. While ozone depletion has been most severe at the poles, there has been a seasonal decline of up to 10 percent of ozone at mid-latitudes, the location of much of North America, South America and Europe. "Since the full recovery of the ozone layer is probably decades away, the amount of UV radiation reaching Earth is likely to remain elevated for some years," she said. "People still need to take precautions when spending time in the sun." Scientific evidence indicates ozone was relatively stable over the past few thousand years, said Weatherhead. The Arctic is the only place in the world where indigenous people were spurred to develop protective mechanisms to shield their eyes from UV radiation, and fossil pigments of plants imply UV radiation has been stable for thousands of years. "It is the past few decades that have been unusual," said Weatherhead. Now ratified by more than 180 nations, the Montreal Protocol established legally binding controls for nations on the production and consumption of halogen gases containing chlorine and bromine. The primary source of ozone destruction is CFCs, once commonly used in refrigeration, air conditioning, foam-blowing equipment and industrial cleaning. About 90 percent of the ozone measured in the study, known as total-column ozone, is found between 10 miles to 20 miles above Earth's surface in the stratosphere, Weatherhead said. The ozone layer protects the planet from the harmful effects of UV radiation, including skin cancer and cataracts in humans and damaging effects on ecosystems.

Ozone Holes

April 10, 2006

https://www.sciencedaily.com/releases/2006/04/060410160525.htm

Satellite Instrument Helps Tackle Mysteries Of Ozone-eating Clouds

Polar stratospheric clouds have become the focus of many research projects in recent years due to the discovery of their role in ozone depletion, but essential aspects of these clouds remain a mystery. MIPAS, an instrument onboard ESA’s Envisat, is allowing scientists to gain information about these clouds necessary for modelling ozone loss.

"The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) is unique in its possibilities to detect polar stratospheric clouds (PSCs) since it is the first instrument with the ability to observe these clouds continuously over the polar regions especially during the polar night," Michael Höpfner of Germany’s Forschungszentrum Karlsruhe GmbH said.Using data collected by MIPAS, a German-designed instrument that observes the atmosphere in middle infrared range, Höpfner and other scientists discovered a belt of nitric acid trihydrate (NAT) PSCs developing in the polar night over Antarctica in 2003 about one month after the first PSCs, which were composed of water crystals, were detected.There are two classifications of PSCs – Type I clouds contain hydrated droplets of nitric acid and sulphuric acid, while Type II clouds consist of relatively pure water ice crystals.The presence of NAT was detected because of MIPAS’ ability to map the atmospheric concentrations of more than 20 trace gases, including ozone as well as the pollutants that attack it.The thinning of the ozone is caused by the presence of man-made pollutants in the atmosphere such as chlorine, originating from man-made pollutants like chlorofluorocarbons (CFCs). During the southern hemisphere winter, temperatures drop to very low levels causing the chemicals in the stratosphere, which is in complete darkness during the winter, to freeze and form PSCs that contain chlorine.Now banned under the Montreal Protocol, CFCs were once widely used in aerosol cans and refrigerators – and have not vanished from the air. CFCs themselves are inert, but ultraviolet radiation high in the atmosphere breaks them down into their constituent parts, which can be highly reactive with ozone.As the polar spring arrives, sunlight returns and creates chemical reactions in PSCs responsible for converting benign forms of chlorine into highly ozone-reactive radicals that spur ozone depletion. A single molecule of chlorine has the potential to break down thousands of molecules of ozone.NAT PSCs enhance the potential for chlorine activation and can also sediment and irreversibly remove nitrogen from the lower stratosphere, causing a process known as denitrification, which slows the return of chlorine to its inactive form and allows for ozone destruction to continue.According to Höpfner, the presence of PSCs could intensify in the future due to a globally changing climate where the Earth’s surface gets warmer due to trapped greenhouse gases but the stratosphere gets colder, providing an environment in which the clouds can form. An increase in PSCs could counteract the recovery of the ozone layer.Although scientific efforts have focused on determining PSC composition and their formation mechanisms, the process causing the ozone depletion is far from understood. In order to gain a better understanding of ozone depletion, scientists must continue obtaining data which allows them to measure the key species involved in the process.

Ozone Holes

April 1, 2006

https://www.sciencedaily.com/releases/2006/04/060401111700.htm

Virginia Tech Studies Reveal Reaction Pathways For Ozone On Organic Surfaces

Virginia Tech chemistry researchers have made a discovery about how ozone degrades organic surfaces such as biological surfactants and polymeric coatings.

The research will be presented at the 231st American Chemical Society (ACS) national meeting being held in Atlanta on March 26-30. John Morris' group is studying the reactions of small molecules found in pollution of surfaces. Morris, associate professor of chemistry in the College of Science, and his students are looking specifically at hydrochloric acid (HCl) and triatomic oxygen (O3, a toxic form of oxygen), pollutants known to play a major role in atmosphere chemistry. They are using functionalized self-assembled monolayers (thin films -- one molecule thick) to simulate organic surfaces. "It gives us control of the surface structure and chemical functionality so we can study how those aspects of a surface influence the fate of important gas-surface collisions," Morris said. The experiments have led to a detailed understanding of the reaction mechanisms of HC1 and ozone on organic surfaces, which is what Morris will present in the paper authored by graduate student Larry R. Fiegland, Morris, and graduate student B. Scott Day. A major finding is that ozone reacts with carbon-carbon double bonds to form crosslinked networks within the thin film. Carbon-carbon double bonds are the very strong forces that link carbon atoms together to help form long-chain molecules -- major components of many polymeric materials found in everyday life. "The formation of crosslinked networks is a new discovery -- that provides a fundamental understanding of how, on the molecular level, organic surfaces degrade with prolonged exposure to ozone, a major atmospheric pollutant," Morris said. "Understanding the reaction mechanism may someday lead to more robust films for organic coatings, or polymeric coatings, such as paints."The paper, "Reaction dynamics of HCl and O3 in collisions with omega-functionalized self-assembled monolayers" (COLL 515), will be presented at 3:30 p.m. at the OMNI at CNN Center International Ballroom F as part of the Division of Colloid and Surface Chemistry symposium honoring ACS Adamson Award Winner Steven Bernasek. Morris' National Science Foundation Career Award funds the research.

Ozone Holes

March 19, 2006

https://www.sciencedaily.com/releases/2006/03/060319183843.htm

Study Links 'Smog' To Arctic Warming

NASA scientists have found that a major form of global air pollution involved in summertime "smog" has also played a significant role in warming the Arctic.

In a global assessment of the impact of ozone on climate warming, scientists at the NASA Goddard Institute for Space Studies (GISS), New York, evaluated how ozone in the lowest part of the atmosphere changed temperatures over the past 100 years. Using the best available estimates of global emissions of gases that produce ozone, the GISS computer model study reveals how much this single air pollutant, and greenhouse gas, has contributed to warming in specific regions of the world.According to this new research, ozone was responsible for one-third to half of the observed warming trend in the Arctic during winter and spring. Ozone is transported from the industrialized countries in the Northern Hemisphere to the Arctic quite efficiently during these seasons. The findings have been accepted for publication in the American Geophysical Union's Journal of Geophysical Research-Atmospheres.Ozone plays several different roles in the Earth’s atmosphere. In the high-altitude region of the stratosphere, ozone acts to shield the planet from harmful ultraviolet radiation. In the lower portion of the atmosphere (the troposphere), ozone can damage human health, crops and ecosystems. Ozone is also a greenhouse gas and contributes to global warming.Ozone is formed from several other chemicals found in the atmosphere near the Earth's surface that come from both natural sources and human activities such as fossil fuel burning, cement manufacturing, fertilizer application and biomass burning. Ozone is one of several air pollutants regulated in the United States by the U. S. Environmental Protection Agency.The impact of ozone air pollution on climate warming is difficult to pinpoint because, unlike other greenhouse gases such as carbon dioxide, ozone does not last long enough in the lower atmosphere to spread uniformly around the globe. Its warming impact is much more closely tied to the region it originated from. To capture this complex picture, GISS scientists used a suite of three-dimensional computer models that starts with data on ozone sources and then tracks how ozone chemically evolved and moved around the world over the past century.The warming impact of low-altitude ozone on the Arctic is very small in the summer months because ozone from other parts of the globe does not have time to reach the region before it is destroyed by chemical reactions fueled by ample sunshine. As a result, when it is summertime in the Northern Hemisphere, ozone-induced warming is largest near the sources of ozone emissions. The computer model showed large summer warming from ozone over western North America and eastern Europe/central Asia, areas with high levels of ozone pollution during that time of year.The new results identify an unexpected benefit of air pollution control efforts worldwide, according to lead author Drew Shindell. "We now see that reducing ozone pollution can not only improve air quality but also have the added benefit of easing climate warming, especially in the Arctic."The research was supported by NASA’s Atmospheric Chemistry Modeling and Analysis Program.

Ozone Holes

February 18, 2006

https://www.sciencedaily.com/releases/2006/02/060216232715.htm

Overseas NOx Could Be Boosting Ozone Levels In US

Large amounts of a chemical that boosts ozone production are being transported to North America from across the Pacific Ocean in May, according to a new report by researchers from Georgia Tech. These higher levels of nitrogen oxides (NOx), arriving in late spring, could be contributing to significant increases in ozone levels over North America. The research appeared in volume 33 of the journal Geophysical Research Letters.

“It’s well-known that pollutants don’t always stay in the region in which they are produced. What’s not understood as well is where and when they travel,” said Yuhang Wang, associate professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology. “Finding this large amount of NOx traveling from across the Pacific is important because it will allow us to build better models so we can better understand how pollutants created in one region of the world are affecting the other regions.”Wang, along with colleagues from Tech, the University of California, Irvine, and the National Center for Atmospheric Research studied data from the Tropospheric Ozone Production about the Spring Equinox (TOPSE) experiment when they found much larger amounts of an array of chemicals, including NOx, and ozone than predicted by current models.Formed when fuel burns at a high temperature, any of the sources of NOx are manmade, with automobile exhaust, electric utilities and industrial activity responsible for the bulk of human-produced NOx. The amount of NOx available largely determines how much ozone, a major component of smog, is produced in most regions of the atmosphere.“With a very small amount of NOx sitting around, as long as you have all these emissions of carbon monoxide and hydrocarbons, the NOx sits there and continuously produces ozone. So in a way you really don’t need a lot of it, but when you have a lot of it, it tends to produce ozone faster,” said Wang.Current models have shown these chemical species coming across the pacific at lower altitudes, but those peak in March and April. Wangs finding that the higher altutide transport occurs in May is significant, not only because they found a large amount of NOx unaccounted for by current models, but the fact that it’s occurring in May means the NOx is more efficient at making ozone.“For the same amount of NOx, ozone production is faster in May than April becauseWhile it’s not clear whether this trans-Pacific transport is coming from Asia or as far away as Europe, given Asia’s proximity and its burgeoning industrial activity, Wang suggests it is the more likely source. The next step in this research is to study chemical measurements over east Asia to see if there is indeed a link to this seasonal transition and emissions from Asia.

Ozone Holes

February 16, 2006

https://www.sciencedaily.com/releases/2006/02/060216231940.htm

Study Finds No Safe Level For Ozone

Even at very low levels, ozone--the principal ingredient in smog--increases the risk of premature death, according to a nationwide study to be published in the April edition of the journal Environmental Health Perspectives.

The study, sponsored by the Environmental Protection Agency and the Centers for Disease Control, found that if a safe level for ozone exists, it is only at very low or natural levels and far below current U.S. and international regulations. A 10 part-per-billion increase in the average of the two previous days' ozone levels is associated with a 0.30 percent increase in mortality. "This study investigates whether there is a threshold level below which ozone does not affect mortality. Our findings show that even if all 98 counties in our study met the current ozone standard every day, there would still be a significant link between ozone and premature mortality," said Michelle Bell, lead investigator on the study and assistant professor of environmental health at the Yale School of Forestry & Environmental Studies. "This indicates that further reductions in ozone pollution would benefit public health, even in areas that meet regulatory requirements." Researchers found that even for days that currently meet the EPA limit for an acceptable level of ozone--80 parts per billion for an eight-hour period--there was still an increased risk of death from the pollutant. An effort is now under way by the EPA to consider whether more stringent standards for ozone are needed. The agency is mandated to set regulations for ozone under the Clean Air Act. Ozone, a gas that occurs naturally in the upper atmosphere, is created in the lower atmosphere when vehicle and industrial emissions react with sunlight. Levels typically rise when sunlight and heat are highest in the summer. "Over 100 million people in the United States live in areas that exceed the National Ambient Air Quality Standard for ozone. Elevated concentrations of ozone are also a growing concern for rapidly developing nations with rising levels of ozone from expanding transportation networks," said Francesca Dominici, co-author of the study and associate professor of biostatistics at Johns Hopkins. The study is online at Yale School of Forestry & Environmental Studies Information on Michell Bell:

Ozone Holes

January 6, 2006

https://www.sciencedaily.com/releases/2006/01/060106125617.htm

Something In The Air? ESA Service Warns Asthma Sufferers By Mobile Phone

We all wonder what is in the air for 2006 - but for people with asthma and other breathing problems, advance knowledge of air pollution levels is very important. An ESA-backed project is forecasting daily forecasts via text message to selected individuals in parts of London and the London borough of Croydon.

As the video above recounts, the service anticipated especially high levels of air pollution during late June 2005, when a concentrated air pollution mass formed over central Europe. The winds carried that pollution to England, with ozone reaching harmful levels in London on 24 to 26 June.However as part of a portfolio of services called PROMOTE, this development was predicted by the sophisticated French air quality modelling service PREV'AIR. Another PROMOTE service, YourAir, then included these inputs when modelling local air quality in the London borough of Croydon. Then, through a trial system called AirTEXT, a warning was sent via SMS text messages to around a thousand people with asthma or other vulnerable conditions, one day in advance of the elevated ozone levels.The YourAir service combines regional air quality forecasts from PROMOTE partners with information on local road traffic patterns. The regional air quality information is important because not all pollution affecting a city actually originates there – studies show that up to half may originate elsewhere.The forecasts include predictions of overall effects on health on an index from one to ten. The YourAir service resolves air pollution down to the scale of individual streets – highest levels are often found along routes with heavy traffic or other pollution sources, so information on street-by-street changes in pollution help vulnerable people make informed choices about their movements.The prototype service covers Central London and Croydon in South London, which is one of the city's largest boroughs by area and the largest by population, with 330 000 inhabitants.The pollution peak shown occurred in the summer, but air quality is a year-round problem. Some of the highest pollution events occur when the meteorological situation means local pollution remains trapped close to the ground to combine with drifting pollution from elsewhere. In London this can often happen during the winter.Maria Ryan, a young mother of three, lives on the edge of Croydon. A mild asthmatic, she is participating in the AirTEXT project: "I'm living close to a main road, and though I don't know if it is connected or not, my asthma has got bad again during the last few years."I check the pollution levels in the newspaper but now I get a forecast by text message a day beforehand. I am glad to get it as a warning to be prepared and take my inhaler with me on a bad day. Going out without it would not be good!"PREV'AIR is coordinated by the French Ministry for Ecology and Sustainable Development. The French National Institute for Industrial Environment and Risks (INERIS) manages the computer system and website and issues daily air quality forecasts. The Pierre-Simon LaPlace Institute is in charge of the CHIMERE chemistry-transport model used for PREV'AIR forecasting, with a variety of other groups including Météo France and the Agency for the Environment and Energy Management (ADEME) providing model input data.The four areas in which PROMOTE services are being developed are air quality, stratospheric ozone, UV exposure and climate change. Partners in the PROMOTE consortium include Météo France, the Norwegian Institute for Air Research (NILU) and the Max Planck Institute in Germany.The project is part of GMES Services – the initial Services Element of Global Monitoring for Environment and Security. This is a joint initiative of ESA and the European Commission to combine all available Earth- and space-based information sources in order to develop an environmental monitoring capability in support of European environment and security goals.

Ozone Holes

December 8, 2005

https://www.sciencedaily.com/releases/2005/12/051207211632.htm

Mountainous Plateau Creates Ozone 'Halo' Around Tibet

Not only is the air around the world's highest mountains thin, but it's thick with ozone, says a new study from University of Toronto researchers.

In fact, say the scientists, the ring of ozone that exists around the Tibetan plateau, which rises 4,000 metres above sea level and includes such famous peaks as Mount Everest and K2, is as concentrated as the ozone found in heavily polluted cities -- and may put climbers at risk. The findings are published in the journal Geophysical Research Letters. "Around the circumference of Tibet, there's a halo of very high levels of ozone," said Professor G.W. Kent Moore, interim chair of the Department of Chemical and Physical Sciences at the University of Toronto at Mississauga and lead author of the study. Study co-author John Semple, an associate professor of surgery and an avid mountaineer, was initially interested in how weather changes at high altitude can have a medical impact on climbers. Along with Moore, he examined earlier data and found several studies that alluded to higher ozone levels. Ozone is a highly reactive gas that can cause coughing, chest pain and damage to the lining of the lungs. "In meteorology, it's a fairly well known phenomenon that when you get storms, quite often the tropopause -- which is the flexible boundary between the stratosphere and the troposphere -- descends," Moore says. "Its usual height might be 12 kilometres, and it might decend to nine or 10 kilometres. If you're on Mount Everest, you're eight or nine kilometres up. It might be that you're sometimes in the stratosphere." The stratosphere is where most of the ozone that protects the globe from the sun's ultraviolet rays can be found;for this reason stratospheric ozone is often referred to as "good" as opposed to the ground-level ozone from pollution which is referred to as "bad". When the tropopause decends, the ozone descends with it. "Most people think about the mountains as one of the areas you can go to get clean air," said Semple, head of the Division of Plastic Surgery at Sunnybrook and Women's College Health Sciences Centre, a teaching hospital affiliated with U of T. "It may be that when you're up high in the mountains that the good ozone actually becomes bad ozone--because no matter where ozone comes from you don't want to breathe it." Semple climbed the Yeli Pass in Bhutan in the autumn of 2004 while collecting data on weather and atmospheric changes. He measured the levels of ozone between 3,000 and 5,000 metres above sea level and discovered that instead of falling (as pollutant levels normally do with altitude), ozone levels were rising. Moore examined satellite measurements of the ozone levels above the plateau during October and November of the years 1997 to 2004. He found that while ozone levels were low over the centre of the Tibetan plateau, high levels of the gas could be found around the periphery of the plateau -- forming a halo. Moore believes that the halo is the result of a pattern in fluid dynamics known as a Taylor column -- a phenomenon that is normally seen underwater. When water passes around a submerged obstacle, like a seamount, the flow of water forks around the obstacle. This forked pattern also continues above the top of the obstruction to the surface of the water, leaving a column of still water above the object. Scientists treat air as a fluid, and Moore says that the Tibetan plateau acts like an obstacle, creating a column of stagnant air above the mountainous region. Because the plateau's influence extends into the upper troposphere and the lower stratosphere -- where the Earth's layer of UV-protectant ozone resides, Moore suggests that the plateau forms a halo of ozone-rich air in the upper-troposphere around Tibet. "As far as we know, this is the first one that's ever been found in the atmosphere," he says. The ozone concentrations measured in this study are still considered quite low in relation to levels that are known to cause significant changes in lung function at sea level. The presence of such higher levels of ozone at extreme altitudes may add to the medical dangers faced by mountaineers. "We can only imagine that hypoxia [lack of oxygen] and the rate of hyperventilation that people have at extreme altitudes would actually make the effects of ozone worse," Semple says. "You probably need less ozone to cause a significant change in the lungs." The research was funded by the Natural Sciences and Engineering Research Council of Canada. The University of Toronto is Canada's leading teaching and research university and aims to be among the world's best. For twelve consecutive years, U of T has taken the top spot among medical/doctoral universities in the annual Maclean's magazine university ranking. With more than 70,000 students, U of T comprises 28 divisions, colleges and faculties on three campuses. This includes 14 professional faculties, nine fully-affiliated teaching hospitals, numerous research centres and Canada's largest university library system -- the third largest in North America.

Ozone Holes

December 8, 2005

https://www.sciencedaily.com/releases/2005/12/051207105911.htm

NASA's AURA Satellite Peers Into Earth's Ozone Hole

NASA researchers, using data from the agency's AURA satellite, determined the seasonal ozone hole that developed over Antarctica this year is smaller than in previous years.

NASA's 2005 assessment of the size and thickness of the ozone layer was the first based on observations from the Ozone Monitoring Instrument on the agency's Aura spacecraft. Aura was launched in 2004.This year's ozone hole measured 9.4 million square miles at its peak between September and mid-October, which was slightly larger than last year's peak. The size of the ozone hole in 1998, the largest ever recorded, averaged 10.1 million square miles. For 10 of the past 12 years, the Antarctic ozone hole has been larger than 7.7 million square miles. Before 1985, it measured less than 4 million square miles.The protective ozone layer over Antarctica annually undergoes a seasonal change, but since the first satellite measurements in 1979, the ozone hole has gotten larger. Human-produced chlorine and bromine chemicals can lead to the destruction of ozone in the stratosphere. By international agreement, these damaging chemicals were banned in 1995, and their levels in the atmosphere are decreasing.Another important factor in how much ozone is destroyed each year is the temperature of the air high in the atmosphere. As with temperatures on the ground, some years are colder than others. When it's colder in the stratosphere, more ozone is destroyed. The 2005 ozone hole was approximately 386,000 square miles larger than it would have been in a year with normal temperatures, because it was colder than average. Only twice in the last decade has the ozone hole shrunk to the size it typically was in the late 1980s. Those years, 2002 and 2004, were the warmest of the period.Scientists also monitor how much ozone there is in the atmosphere from the ground to space. The thickness of the Antarctic ozone layer was the third highest of the last decade, as measured by the lowest reading recorded during the year. The level was 102 Dobson Units (the system of measurement designated to gauge ozone thickness). That is approximately one-half as thick as the layer before 1980 during the same time of year.The Ozone Monitoring Instrument is the latest in a series of ozone-observing instruments flown by NASA over the last two decades. This instrument provides a more detailed view of ozone and is also able to monitor chemicals involved in ozone destruction. The instrument is a contribution to the mission from the Netherlands' Agency for Aerospace Programs in collaboration with the Finnish Meteorological Institute. The Royal Netherlands Meteorological Institute is the principal investigator on the instrument.

Ozone Holes

November 17, 2005

https://www.sciencedaily.com/releases/2005/11/051117013633.htm

Ozone Levels May Raise Risk Of Underweight Births: Common Pollutants Linked To Fetal Growth Retardation

Babies born to women exposed to high ozone levels during pregnancy are at heightened risk for being significantly underweight, according to researchers at the Keck School of Medicine of the University of Southern California.

Women who breathe air heavily polluted with ozone are at particular risk for having babies afflicted with intra uterine growth retardation-which means babies only fall within the 15th percentile of their expected size. The findings were published early online on the Web site of Environmental Health Perspectives, the journal of the National Institute for Environmental Health Sciences (NIEHS). "These findings add further evidence that our ozone standards are not protecting the most vulnerable members of the population," says Frank D. Gilliland, M.D., Ph.D., professor of preventive medicine at the Keck School and the study's senior author. Gilliland and his colleagues examined birth records from 3,901 children who were born in California between 1975 and 1987 and participated in the Children's Health Study. Researchers with the USC-led Children's Health Study have monitored levels of major pollutants in a dozen Southern California communities since 1993, while following the respiratory health of more than 6,000 students in those communities. The researchers gathered data such as the children's gestational age and birth weight, as well as their mothers' zip code of residence at birth. Then they determined levels of ozone, carbon monoxide and other pollutants in the air in each zip code of residence during each mother's pregnancy. Researchers only considered full-term births for the study and controlled for factors such as mothers' smoking habits. They found that each increase of 12 parts per billion (ppb) of average daily ozone levels over a mother's entire pregnancy was associated with a drop of 47.2 grams (g)-about a tenth of a pound-in a baby's birth weight. And the association was even stronger for ozone exposure over the second and third trimesters, Gilliland says. In addition, for each 17 ppb increase in average daily ozone levels during a mother's third trimester of pregnancy, the risk of intra uterine growth retardation increased by 20 percent, the scientists report. The effects were strongest when total average daily ozone exposure rose above 30 ppb. Ozone levels varied from less than 20 ppb in cleaner areas to above 40 ppb in more polluted areas of Southern California. Carbon monoxide levels affected birth weight as well. They found that each increase of 1.4 parts per million of carbon monoxide concentration during the first trimester was associated with 21.7 g (about .05 pound) decrease in birth weight and a 20 percent increase in risk of intra uterine growth retardation. Ozone, or O3, is a gas made up of three oxygen atoms. Although a natural layer of ozone in the stratosphere helps protect life on Earth from the sun's rays, ozone at ground level is harmful to health. It is created through interactions among tailpipe exhaust, gasoline vapors, industrial emissions, chemical solvents and natural sources and is worsened by sunlight and heat. The study findings echo results from the few, smaller studies examining the relationship between ozone and birth weight. Animal studies support the role of O3 in reduced birth weight: in these models, pregnant rats were particularly vulnerable to lung inflammation from O3. Researchers suspect that inflammation from O3 may prompt the release of certain chemicals into the bloodstream, which may harm the placenta. Carbon monoxide, meanwhile, is an odorless gas that primarily comes from vehicle exhaust. In high concentrations, the gas can harm healthy people; and in lower concentrations, it can hurt those with heart disease and can affect the nervous system. The gas reduces hemoglobin's ability to carry oxygen where it is needed in the body; that may hurt the delivery of oxygen to a fetus. However, more research is needed to understand the roles of ozone and carbon monoxide in fetal development. "Fetal growth and birth weight are strongly linked to morbidity and mortality during childhood and adulthood," Gilliland says, "so it's clear that air quality is important to everyone's healthy development." Research was supported by the NIEHS, the Environmental Protection Agency, National Heart, Lung and Blood Institute, California Air Resources Board and the Hastings Foundation. Muhammad T. Salam, Joshua Millstein, Yu-Fen Li, Frederick W. Lurmann, Helene G. Margolis and Frank Gilliland, "Birth Outcomes and Prenatal Exposure to Ozone, Carbon Monoxide and Particulate Matter: Results from the Children's Health Study, Environmental Health Perspectives. Vol. 113, No. 11, November 2005, pp. 1638-1644.

Ozone Holes

November 9, 2005

https://www.sciencedaily.com/releases/2005/11/051109094249.htm

Software Fills In Missing Data On Satellite Images

New software is helping scientists get a more complete view of the environment from satellites that orbit the earth.

Maps that depict the thickness of the ozone layer, for instance, frequently contain blank spots where a satellite wasn't able to record data on a particular day, explained Noel Cressie, professor of statistics and director of the Program in Spatial Statistics and Environmental Sciences (SSES) at Ohio State University. He and his colleagues found a way to use data from the rest of a map as well as from previous days to fill in the blank spots. The same technique could be used in studies of agricultural data or even medical imaging. When it comes to mapping the environment, satellites gather so much data every day that filling in the missing parts quickly is a challenge. "Right now, from a statistical point of view, people can either fill in these maps well, but not very fast -- or fill them in fast but not very well," Cressie said. "We do it well and we do it fast." By his estimate, if someone were to try to complete an ozone map in a way that was as statistically precise as possible, processing one day's worth of data could take 500 years. The Ohio State software does the job in about three minutes. It also calculates a measure of map precision. The varying precision in different parts of the completed map gives scientists valuable information about the quality of the data they use to construct computer models of Earth's climate system. Cressie began this project with former student Hsin-Cheng Huang. Another student, Gardar Johannesson, completed the work for his doctoral dissertation at Ohio State. In an upcoming issue of the journal Environmental and Ecological Statistics, Johannesson, Cressie and Huang cite NASA's need for new ways to process satellite data as the motivation for their work. In fact, NASA already uses well-established techniques to fill in gaps in satellite imagery, but the task is becoming more difficult. At any moment, NASA satellites are recording global ocean and air temperatures, wind speeds, and amounts of atmospheric molecules such as ozone. The data come in at a rate of 1.5 terabytes (1.5 trillion bytes) a day. That's as much information as is contained in 1,500 copies of the Encyclopedia Britannica, or nearly 200 DVD movies. Future satellites will be able to gather even more data, much faster. But as long as conditions like cloud cover or on-board electrical problems interfere with satellite instruments, missing data will always be an issue.One way to fill in blank pixels on a satellite image is to use the average value of all the data points in nearby pixels. But averaging the data means losing potentially valuable details. Plus, there are important spatial relationships among the data that typical methods don't account for, in order to achieve faster computing. That means scientists can't appropriately measure the precision of the spatial data they are filling in when they use the normal methods. "People have been developing methods to do this -- to fill in missing data and provide measures of how accurately they are doing so. But the methods often do not do well with massive amounts of data," said Johannesson, who now works at Lawrence Livermore National Laboratory. Huang is now with the Institute of Statistical Science at Academia Sinica in Taiwan . The researchers developed statistical techniques that fill in missing data by performing calculations at different image resolutions. First, the software "zooms out" of the image to calculate potential values for the missing pieces at low resolution, then it zooms back in to refine the calculations at higher resolutions. Data from the surrounding pixels -- on that day and previous days -- all help determine the outcome. The study details the application of the software to a month's worth of ozone data. To further test their methods, the statisticians also artificially removed the data from a slice of the ozone map above the Pacific Ocean for one day, and then used the software to calculate the missing piece. The results very closely matched the actual data. Key to the technique is that it draws from a statistical method called Bayesian analysis to weight the available data in the calculations. Reliable data count the most; less reliable data count less, but they still count. Cressie would like to see NASA and other organizations try out the software for ozone modeling or other applications. Any study that charts how some characteristic changes in space or time -- such as the health of crops in a field or the features in a medical image -- could benefit from using the methodology. Until then, he's published some details of the technology as well as animations of ozone data on the SSES Program's Web site. This work was partially funded by the Office of Naval Research.

Ozone Holes

October 27, 2005

https://www.sciencedaily.com/releases/2005/10/051027084507.htm

Tropical Cloud 'Dust' Could Hold The Key To Climate Change

Scientists at the University of Manchester will set off for Australia this week to undertake an in-depth study of tropical clouds and the particles sucked up into them to gain further insight into climate change and the depletion of the ozone layer.

The research will take place in Darwin, Australia as part of a major international field experiment to study transport by tropical thunderstorms and the type of high-altitude clouds they produce.Manchester's research will focus on the analysis of tiny particles, known as aerosols, which determine cloud properties. Aerosols include materials like desert dust, sea salt and other organic materials which are drawn up into the clouds from the earth's surface. These particles control the physics of the clouds and can have a dramatic effect on the climate.The aim of the experiment is to gain a better understanding of the kind of aerosol particles and gases which are injected by the storms into the Tropical Tropopause Layer, a poorly-understood region of the atmosphere sandwiched between the main tropical weather systems and the stratosphere above.Data will be collected by two planes carrying high-tech monitoring equipment at different altitudes through a series of storms over a four month period. The data will then be used to create computer models of the clouds and the chemicals contained within them.Professor Geraint Vaughan, of the University's School of Earth, Atmospheric and Environmental Sciences, who will lead the study, said: "The tropics drives global atmospheric circulation, so it is extremely important for us to understand how atmospheric processes operate there."Deep thunderstorms are a major feature of tropical weather, but their overall effect on the transport of material to high levels is poorly understood. This is important because it helps determine the composition of the stratosphere and the kinds of clouds which form high in the atmosphere."He added: "If we can understand the nature and composition of these clouds, we will be able to use this information to help predict future climate change."The research is being undertaken as part of the Natural Environment Research Council's (NERC) £1.6 million ACTIVE project. The research team will use the Australian Egrett aircraft and the NERC's Dornier aircraft to measure chemical and aerosol which are drawn into and expelled from tropical storms. The measurements will be interpreted using cloud-scale and large-scale modelling to distinguish the contribution of different sources to the Tropical Tropopause Layer.ACTIVE is a NERC-funded consortium project involving the Universities of Manchester, Cambridge and, York (UK); DLR and Forschungszentrum Julich (Germany); York University (Canada), Bureau of Meteorology (Australia) and Airborne Research Australia.

Ozone Holes

August 30, 2005

https://www.sciencedaily.com/releases/2005/08/050830065621.htm

Ozone Layer Decline Leveling Off, According To New Study

A new global study involving long-term data from satellites and groundstations indicates Earth's ozone layer, while still severely depletedfollowing decades of thinning from industrial chemicals in theatmosphere, is no longer in decline.

Betsy Weatherhead, a researcher with the Cooperative Institute forResearch in Environmental Sciences, a joint institute of the Universityof Colorado at Boulder and the National Oceanic and AtmosphericAdministration and corresponding author of the study, said the teamdocumented a leveling off of declining ozone levels between 1996 and2002, and even measured small increases in some regions. "The observed changes may be evidence of ozone improvement inthe atmosphere," said Weatherhead. "But we will have to continue tomonitor ozone levels for years to come before we can be confident." It most likely will be decades before the ozone layerrecovers, and it may never stabilize at the levels measured prior tothe mid-1970s, when scientists discovered human-produced chlorine andbromine compounds could destroy ozone and deplete the ozone layer,Weatherhead said. A paper on the subject involving researchers from CU-Boulder,NOAA, the University of Wisconsin Madison, the University of Chicagoand the University of Illinois was published online Aug. 29 in theJournal of Geophysical Research. The halt in the ozone decline follows the 1987 MontrealProtocol, an international agreement now ratified by more than 180nations that established legally binding controls for nations on theproduction and consumption of halogen gases containing chlorine andbromine. Scientists say the primary source of ozone destruction ischlorofluorocarbons, or CFC's, which once were commonly used inrefrigeration, air conditioning, foam-blowing equipment and industrialcleaning. The new statistical study focused on levels of total-columnozone -- ozone existing between Earth's surface and the top of theatmosphere. Total-column ozone is a primary blocker of UV radiation inthe atmosphere. The team analyzed data from a cadre of NASA and NOAAsatellites as well as ground stations in North America, Europe, Hawaii,Australia and New Zealand. About 90 percent of total-column ozone is found between 10miles to 20 miles above Earth's surface in the stratosphere,Weatherhead said. The ozone layer protects the planet from the harmfuleffects of UV radiation, including skin cancer and cataracts in humansand damaging effects on ecosystems. Despite the new evidence for the beginnings of an ozonerecovery, Mike Repacholi, The World Health Organization's environmentalhealth coordinator in Geneva, warned that precautions such asUV-blocking sunglasses and skin protection remain vital. "This studyprovides some very encouraging news," he said. "But the major cause ofskin cancer is still human behavior, including tanning and sunburnsthat result from a lack of proper skin protection." Ozone depletion has been most severe at the poles, with levelsdeclining by as much as 40 percent on a seasonal basis, saidWeatherhead. But there also has been as much as a 10 percent seasonaldecline at mid-latitudes, the location of much of North America, SouthAmerica and Europe. Other anthropogenic changes to the atmosphere such as methanelevels, water vapor and air temperatures will affect future ozonelevels, which are naturally maintained by complex chemical processessparking the continual creation, destruction and redistribution ofozone, said Weatherhead. "Even after all chlorine compounds are out ofthe system, it is unlikely that ozone levels will stabilize at the samelevels." Scientists warn a return to significantly higher atmosphericozone levels may take up to 40 years. "Chemicals pumped into Earth'satmosphere decades ago still are affecting ozone levels today," saidSherwood Roland of the University of California, Irvine, who shared the1995 Nobel Prize in Chemistry with Paul Crutzen and Mario Molina fortheir work in identifying the CFC threat to the ozone layer. "Thisproblem was a long time in the making, and because of the persistenceof these chlorine compounds, there is no short-term fix." Greg Reinsel, a UW Madison researcher and the lead author ofthe study, was one of the first scientists to quantify the ozonedecline more than two decades ago. He died unexpectedly in May aftercompleting the study. Other co-authors include NOAA's Alvin Miller, Lawrence Flynnand Ron Nagatani, George Tiao of the University of Chicago and DonWuebbles of the University of Illinois. More UV radiation information is available at:

Ozone Holes

July 19, 2005

https://www.sciencedaily.com/releases/2005/07/050718214744.htm

Methane's Impacts On Climate Change May Be Twice Previous Estimates

Scientists face difficult challenges in predicting and understanding how much our climate is changing. When it comes to gases that trap heat in our atmosphere, called greenhouse gases (GHGs), scientists typically look at how much of the gases exist in the atmosphere.

However, Drew Shindell, a climatologist at NASA's Goddard Institute for Space Studies, New York, NY, believes we need to look at the GHGs when they are emitted at Earth's surface, instead of looking at the GHGs themselves after they have been mixed into the atmosphere. "The gas molecules undergo chemical changes and once they do, looking at them after they've mixed and changed in the atmosphere doesn't give an accurate picture of their effect," Shindell said. "For example, the amount of methane in the atmosphere is affected by pollutants that change methane's chemistry, and it doesn't reflect the effects of methane on other greenhouse gases," said Shindell, "so it's not directly related to emissions, which are what we set policies for."Chemically reactive GHGs include methane and ozone (carbon dioxide, the most important GHG, is largely unreactive). Once methane and the molecules that create ozone are released into the air by both natural and human-induced sources, these gases mix and react together, which transforms their compositions. When gases are altered, their contribution to the greenhouse warming effect also shifts. So, the true effect of a single GHG emission on climate becomes very hard to single out. Some of the major investigations into the state of our warming planet come from a series of reports from the Intergovernmental Panel on Climate Change (IPCC) Assessment. These reports involved the work of hundreds of climate experts. The reports rely on measurements of greenhouse gases as they exist in the atmosphere, after they may have mixed with other gases. In other words, the findings in the report do not reflect the quantities that were actually emitted.Shindell finds there are advantages to measuring emissions of greenhouse gases and isolating their impacts, as opposed to analyzing them after they have mixed in the atmosphere. His study on the subject was recently published in the journal Geophysical Research Letters. In the study, when the individual effects of each gas on global warming were added together, the total was within 10 percent of the impacts of all the gases mixed together. The small difference in the two amounts was a sign to Shindell that little error was introduced by separating the emissions from one another. After isolating each greenhouse gas and calculating the impact of each emission on our climate with a computer model, Shindell and his colleagues found some striking differences in how much these gases contribute overall to climate change. The leading greenhouse gases include carbon dioxide, methane, nitrous oxide, and halocarbons. These gases are called ‘well mixed’ greenhouse gases because of their long lifetimes of a decade or more, which allows them to disperse evenly around the atmosphere. They are emitted from both man-made and natural sources. Ozone in the lower atmosphere, called tropospheric ozone, a major component of polluted air or smog that is damaging to human and ecosystem health, also has greenhouse warming effects. In the upper atmosphere, ozone protects life on Earth from the sun’s harmful ultraviolet rays. According to new calculations, the impacts of methane on climate warming may be double the standard amount attributed to the gas. The new interpretations reveal methane emissions may account for a third of the climate warming from well-mixed greenhouse gases between the 1750s and today. The IPCC report, which calculates methane’s affects once it exists in the atmosphere, states that methane increases in our atmosphere account for only about one sixth of the total effect of well-mixed greenhouse gases on warming.Part of the reason the new calculations give a larger effect is that they include the sizeable impact of methane emissions on tropospheric ozone since the industrial revolution. Tropospheric ozone is not directly emitted, but is instead formed chemically from methane, other hydrocarbons, carbon monoxide and nitrogen oxides. The IPCC report includes the effects of tropospheric ozone increases on climate, but it is not attributed to particular sources. By categorizing the climate effects according to emissions, Shindell and colleagues found the total effects of methane emissions are substantially larger. In other words, the true source of some of the warming that is normally attributed to tropospheric ozone is really due to methane that leads to increased abundance of tropospheric ozone. According to the study, the effects of other pollutants were relatively minor. Nitrogen oxide emissions can even lead to cooling by fostering chemical reactions that destroy methane. This is partly why estimates based on the amount of methane in the atmosphere give the gas a smaller contribution to climate change.Molecule for molecule, Methane is 20 times more potent than carbon dioxide as a greenhouse gas, but CO2 is much more abundant than methane and the predicted growth rate is far greater. Since 1750, methane concentrations in the atmosphere have more than doubled, though the rate of increase has slowed during the 1980-90s, and researchers don’t understand why. Controlling methane could reap a big bang for the buck. Another bonus of this perspective is that in order to manage greenhouse gases, policy decisions must focus on cutting emissions, because that's where humans have some control. "If we control methane, which the U.S. is already starting to do, then we are likely to mitigate global warming more than one would have thought, so that's a very positive outcome," Shindell said. "Control of methane emissions turns out to be a more powerful lever to control global warming than would be anticipated." Sources of methane include natural sources like wetlands, gas hydrates in the ocean floor, permafrost, termites, oceans, freshwater bodies, and non-wetland soils. Fossil fuels, cattle, landfills and rice paddies are the main human-related sources. Previous studies have shown that new rice harvesting techniques can significantly reduce methane emissions and increase yields.

Ozone Holes

July 14, 2005

https://www.sciencedaily.com/releases/2005/07/050712225601.htm

Boosting Vitamin C In Plants Can Help Reduce Smog Damage

The harmful effects of smog on people and animals – the stinging eyes and decreased lung capacity – are the stuff of well-researched fact. Now, the body of knowledge about air pollution’s effects on plants has grown with University of California, Riverside Biochemistry Professor Daniel Gallie’s discovery of the importance of vitamin C in helping plants defend themselves against the ravages of ozone – smog’s particularly nasty component.

By manipulating dehydroascorbate reductase (DHAR), a naturally occurring enzyme that recycles vitamin C, to increase the level of the vitamin in leaves, Gallie has been able to reduce the harmful effects of ozone on plants, apparent as brown spots, stunted size, and lowered crop yields. He and Assistant Research Biochemist Dr. Zhong Chen published their findings in a recent paper titled Increasing Tolerance to Ozone by Elevating Foliar Ascorbic Acid Confers Greater Protection Against Ozone Than Increasing Avoidance, in the journal “Plant Physiology.”Gallie’s previous research found that plants react to smog much like they react to drought, by closing pores (called stomata) present in their leaves. The closed pores protect plants from losing water and taking in ozone, but also prevent the production of sugars through photosynthesis, which are needed for the plant to grow.“It’s clearly not an effective strategy to protect plants from the effects of long-term exposure to smog,” Gallie said.Plants, he said, have two options to defend themselves from ozone. They can prevent ozone from entering the leaf by closing their stomata, or use the antioxidant qualities of vitamin C to detoxify the ozone that enters through open stomata and also protect the photosynthetic machinery in the leaf.Studying acute and chronic ozone exposures, Gallie and Chen looked at which plants fared better, those with lower levels of vitamin C that closed their pores or those with higher levels of vitamin C, open pores, and higher levels of photosynthetic activity. Those with the higher levels of vitamin C fared better in the long run, in both instances, despite the fact that more ozone entered through the open pores of the leaf, Gallie said.Gallie and Chen’s findings offer a clear direction for a strategy toward developing plants that will be able to grow and thrive in high-ozone environments such as cities and suburban areas.“Because we’re seeing, especially in this country, the encroachment of urban areas into farm lands, we’re seeing an increased impact on agriculture. Moreover, ornamental plants used for urban and suburban landscaping are heavily affected by exposure to smog,” said Gallie.The next step in Gallie’s research will focus on the apparent correlation between a plant’s increased vitamin C levels and increased photosynthetic activity.“There seems to be multiple benefits of increasing the level of vitamin C in plants, including improving their tolerance to smog, improving photosynthesis, and improving their nutritional quality but more research is clearly needed,” he said.The key question, at least in the near term, is to determine whether increased vitamin C and photosynthesis will result in greater crop yields, he added.

Ozone Holes

July 3, 2005

https://www.sciencedaily.com/releases/2005/06/050630063151.htm

NCAR Analysis Shows Widespread Pollution From 2004 Wildfires

BOULDER—Wildfires in Alaska and Canada in 2004 emitted about as much carbon monoxide as did human-related activities in the continental United States during the same time period, according to new research by the National Center for Atmospheric Research (NCAR). The fires also increased atmospheric concentrations of ground-level ozone across much of the Northern Hemisphere.

The NCAR study, which indicates the extent to which wildfires contribute to atmospheric pollution, was published this month in Geophysical Research Letters. The researchers used a novel combination of observing instruments, computer models, and numerical techniques that allowed them to distinguish between carbon monoxide coming from the wildfires and from other sources.The team concluded that the Alaskan and Canadian wildfires emitted about 30 teragrams of carbon monoxide from June through August of last year. Because of the wildfires, ground-level concentrations of ozone increased by 25% or more in parts of the northern continental United States and by 10% as far away as Europe."It is important to see how the influence of these fires can reach large parts of the atmosphere, perhaps even over the entire Northern Hemisphere," says NCAR scientist Gabriele Pfister, the study's lead author. "This has significant implications as societies take steps to improve air quality."Carbon monoxide, a toxic gas that can affect human health even at low levels, is emitted by wildfires as well as by motor vehicles, industrial facilities, and other sources that do not completely burn carbon-containing fuels. Ground-level ozone, which affects human health in addition to damaging plants and influencing climate, is formed from reactions involving atmospheric pollutants, including carbon monoxide, in the presence of sunlight. Both pollutants are monitored by the Environmental Protection Agency. However, scientists have been unable to precisely determine regional emissions of carbon monoxide or the extent to which human and natural activities contribute to atmospheric concentrations of the gas.Wildfires in Alaska and western Canada were particularly intense in the summer of 2004, largely because of unusually warm and dry weather. To quantify carbon monoxide emissions from the fires, the research team used a remote sensing instrument known as MOPITT (Measurements of Pollution in the Troposphere) that is operated by NCAR and the University of Toronto and flown on NASA's Terra satellite. The scientists simulated the transport of the pollutants emitted by the fires and the resulting production of ozone with an NCAR computer model called MOZART (Model for Ozone and Related Chemical Tracers).The team confirmed its results by using numerical techniques to compare simulated concentrations of carbon monoxide in the atmosphere with measurements taken by MOPITT. The researchers were able to get further confirmation by analyzing data from aircraft-mounted instruments that were taking part in a field project over North America and Europe.Pfister says the team is continuing to look at data taken last year at observing stations as far away as the Azores in order to track the movement of carbon monoxide and ozone from the wildfires. As a follow-up, she and other scientists plan to use a similar combination of observations, modeling, and numerical techniques to look at both natural and human-related emissions of carbon monoxide in South America.The research was funded by a NASA grant in partnership with the National Science Foundation, which is the primary sponsor of NCAR.

Ozone Holes

June 14, 2005

https://www.sciencedaily.com/releases/2005/06/050614235451.htm

Plant Pathologists Evaluate Eco-friendly Alternatives To Methyl Bromide

St. Paul, Minn. (June 13, 2005) - Alternatives to a powerful pesticide that was found be an ozone depletor are now being evaluated in agricultural production areas of Florida, say plant pathologists with USDA's Agricultural Research Service.

In 1987, the Parties to the Montreal Protocol called for the phase-out of methyl bromide, a soil fumigant used to control soilborne fungi, nematodes, and weeds of more than 100 crops worldwide. The phase out was based on methyl bromide's ability to deplete ozone and disrupt the UV protective ozone layer. The EPA determined that, under the Clean Air Act, this fumigant must be phased-out by 2001, but in compliance with the Protocol, the complete phase-out was scheduled for 2005. Currently, only uses deemed as critical by the international Methyl Bromide Technical Options Committee can obtain the material. Because methyl bromide is considered essential for the production of pepper, strawberry, tomato, and floriculture crops in Florida, scientists in many disciplines have been researching chemical and non-chemical methyl bromide replacements in the state's agricultural areas. Soil solarization, a technique that captures radiant heat energy from the sun, is one non-chemical alternative to methyl bromide. Another non-chemical alternative is the use of biological agents to enhance disease resistance such as plant growth-promoting rhizobacteria (PGPR), which are beneficial soil bacteria that colonize plant roots and protect against disease. "An integrated approach that utilizes biologically-based pest management tactics, such as PGPRs, soil solarization, and biological control agents combined with crop rotations and cover crops will be a necessity in the future," said Erin Rosskopf, USDA-ARS, U.S. Horticultural Research Laboratory, Fort Pierce, FL. "A multi-tactic approach is becoming increasingly important as many agricultural chemicals undergo intense scrutiny with regard to human toxicity and environmental impact. It is critical that research in these areas continues to move forward so that the next phase-out does not result in decreased vegetable or ornamental production in Florida and the rest of the U.S.," Rosskopf said. Attempts to identify chemical alternatives to methyl bromide have led to the re-examination of existing soil fumigants. "While an emphasis is currently being placed on the short-term chemical replacements for methyl bromide due to the urgency driven by the phase-out plan, there is a need to be visionary in the development of more sustainable production systems for methyl bromide-dependent crops," said Rosskopf. A number of chemical alternatives to methyl bromide are currently being investigated for efficacy with several still in the registration process. More on the alternatives to methyl bromide now used in Florida is available in this month's APS feature article at The American Phytopathological Society (APS) is a non-profit, professional scientific organization. The research of the organization's 5,000 worldwide members advances the understanding of the science of plant pathology and its application to plant health.

Ozone Holes

June 13, 2005

https://www.sciencedaily.com/releases/2005/06/050613062535.htm

Ozone Levels Drop When Hurricanes Are Strengthening

Scientists are continually exploring different aspects of hurricanes to increase the understanding of how they behave. Recently, NASA-funded scientists from Florida State University looked at ozone around hurricanes and found that ozone levels drop as a hurricane is intensifying.

In a recent study, Xiaolei Zou and Yonghui Wu, researchers at Florida State University found that variations of ozone levels from the surface to the upper atmosphere are closely related to the formation, intensification and movement of a hurricane.They studied ozone levels in 12 hurricanes and looked at total ozone levels, that is, from the ground to the upper atmosphere. Now scientists have clues on how a hurricane behaves when the ozone levels are high and low.Zou and Wu noticed that over 100 miles, the area of a hurricane typically has low levels of ozone from the surface to the top of the hurricane. Whenever a hurricane intensifies, it appears that the ozone levels throughout the storm decrease. When they looked at the storm with ozone data a hurricane's eye becomes very clear. Because forecasters always try to pinpoint the eye of the hurricane, this knowledge will help with locating the exact position and lead to better tracking.The National Oceanic and Atmospheric Administration's National Hurricane Center (NHC) is the agency that issues hurricane forecasts. Out of the 12 storms analyzed, the ozone data and the NHC official report differed on the mean distance between the estimated eye by less than 18 miles during the most intense stage of the storms. As such, when Zou and Wu added the satellite observed ozone levels around a hurricane into a computer forecast model, it greatly improved the predicted track that the hurricane would take."This research highlights the benefits of Total Ozone Mapping Spectrometer (TOMS) data in hurricane track and intensity prediction, an important forecasting problem since hurricanes strike regions of high population and property growth, resulting in large natural disasters," said Zou.The other interesting finding when analyzing ozone data around hurricanes, is that ozone levels give a clue that a storm will develop before other methods. The early spin of a tropical cyclone is weak and sometimes covered by clouds, and not easily detected by satellites that provide pictures of clouds. The ozone data gives scientists a "look beyond the clouds."Ozone is all around the world and in the upper and lower atmosphere. Ozone in the upper atmosphere protects life on Earth from harmful ultraviolet rays from the sun, which can cause sunburn and skin cancer. Ozone close to the surface is a pollutant, which on hot, humid days with little wind creates a haze, such as that over big cities, that is harmful to breathe.By using NASA's satellite Earth Probe/ TOMS total ozone data, forecasters can identify ozone amounts that are closely related to the formation, intensification, and movement of a hurricane. Zou and Wu also found a strong relationship between ozone, air pressure and spin within the hurricanes.Zou said that the connections between ozone levels and hurricane behavior are a very important step in understanding the storms.

Ozone Holes

June 8, 2005

https://www.sciencedaily.com/releases/2005/06/050607005449.htm

Soil Emissions Are Much-bigger-than-expected Component Of Air Pollution

Nitrogen oxides produced by huge fires and fossil fuel combustion are a major component of air pollution. They are the primary ingredients in ground-level ozone, a pollutant harmful to human health and vegetation.

But new research led by a University of Washington atmospheric scientist shows that, in some regions, nitrogen oxides emitted by the soil are much greater than expected and could play a substantially larger role in seasonal air pollution than previously believed.Nitrogen oxide emissions total more than 40 million metric tons worldwide each year, with 64 percent coming from fossil fuel combustion, 14 percent from burning and a surprising 22 percent from soil, said Lyatt Jaeglé, a UW assistant professor of atmospheric sciences. The new research shows that the component from soil is about 70 percent greater than scientists expected.Instead of relying on scattered ground-based measurements of burning and combustion and then extrapolating a global total for nitrogen oxide emissions, the new work used actual observations recorded in 2000 by the Global Ozone Monitoring Experiment aboard the European Space Agency's European Remote Sensing 2 satellite.Nitrogen oxide emissions from fossil fuel combustion are most closely linked to major population centers and show up in the satellite's ozone-monitoring measurements of nitrogen dioxide, part of the nitrogen oxides family. Other satellite instruments can detect large fires and the resulting emissions also can be measured by the ozone-monitoring experiment, Jaeglé said.But the satellite also picks up other nitrogen oxide signals not attributable to fuel combustion or burning, and those emissions must come from soil, Jaeglé said."We were really amazed that we could see it from space, but because the pulse is so big the satellite can see it," she said.Soil emissions are seen primarily in equatorial Africa at the beginning of the rainy season, especially in a region called the Sahel, and in the mid-latitudes of the Northern Hemisphere during summer. When the rains come to the Sahel after a six-month dry season, dormant soil bacteria reawaken and begin processing nitrogen. The satellite then detects a sudden pulse of nitrogen oxides, Jaeglé said. Similarly, emissions in the mid-latitudes of the Northern Hemisphere spike during the growing season, spurred by warmer temperatures after a cold winter, but also perhaps magnified by fertilizer use."The soil emissions were much larger than we expected," she said. "The biggest areas were the dry topical regions like the Sahel, and in the mid-latitude regions where there is a lot of agriculture."During summer in North America, Europe and Asia, nitrogen oxides emitted from soil can reach half the emissions from fossil fuel combustion."And this is at a time when there are already problems with air pollution," Jaeglé said.Nitrogen oxides comprise a group of highly reactive gases containing nitrogen and oxygen in varying amounts. Besides producing ozone smog, they help form the dirty brown clouds that often hang over major cities, they contribute to acid rain and they play a role in global climate change.In addition to equatorial Africa, hot spots for soil emissions include the central plains of the United States; southwestern Europe, primarily the Iberian Peninsula; much of India; and the northern plains of Asia, she said. All of those areas are highly agricultural.The new research was published in May in Faraday Discussions, a journal of England's Royal Society of Chemistry. Co-authors are Linda Steinberger of the UW; Randall Martin of Dalhousie University in Halifax, Nova Scotia; and Kelly Chance of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. The work was funded by the National Aeronautics and Space Administration's New Investigator Program in Earth Science.Jaeglé noted that agricultural activity is likely to increase in the future, bringing more fertilizer use. As a result, there could also be even greater soil emissions of nitrogen oxides."We don't know how emissions will change, but we now have a way to monitor them from space," she said.

Ozone Holes