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July 18, 2014

https://www.sciencedaily.com/releases/2014/07/140718102517.htm

Ten-year endeavor: NASA's Aura tracks pollutants

NASA's Aura satellite, celebrating its 10th anniversary on July 15, has provided vital data about the cause, concentrations and impact of major air pollutants. With instruments providing key measurements of various gases -- including two built and managed by NASA's Jet Propulsion Laboratory: the Tropospheric Emission Spectrometer (TES) and Microwave Limb Sounder (MLS) -- Aura gives a comprehensive view of one of the most important parts of Earth -- the atmosphere.

Aura has improved our understanding of ozone, a versatile gas that both benefits and harms the atmosphere, depending on its location. Near the ground, ozone is a pollutant that damages plants and can decrease lung function in humans. Somewhat higher in the atmosphere, ozone affects climate as a greenhouse gas. Aura's TES instrument provides measurements of ozone and other greenhouse gases.The majority of ozone, about 90 percent, is even higher -- in the stratosphere, 12 to 90 miles above the surface -- where it shields us from the sun's ultraviolet light and makes life possible on Earth. Over the Antarctic, cold temperatures and human-produced chlorine gases destroy ozone each spring. Scientists use Aura's Microwave Limb Sounder (MLS) instrument to measure ozone and other trace gases in and around the ozone hole every year. In 2006 and 2011, Aura's instruments revealed two of the largest and deepest ozone holes in the past decade, and also helped scientists understand the different causes of the two large holes.Shortly after Aura's launch, the Ozone Monitoring Instrument (OMI) began monitoring levels of another major pollutant -- nitrogen dioxide. This brownish gas can lead to respiratory problems and is an ingredient in ground-level ozone pollution. OMI data show that nitrogen dioxide levels in the United States decreased 4 percent per year from 2005 to 2010, a time when stricter policies on power plant and vehicle emissions came into effect. As a result, concentrations of ground-level ozone also decreased. During the same period, global nitrogen dioxide levels increased a little over half a percent per year. China's level increased about 6 percent per year.OMI also measures sulfur dioxide, a gas that combines with other chemicals in clouds to produce acid rain or reacts to form sulfate aerosols, which affect health and climate. OMI has identified large concentrations of sulfur dioxide around power plants and volcanoes.Aura's decade of work has set the stage for future air quality monitoring instruments. The European Space Agency will be launching the follow-up TROPOspheric Monitoring Instrument, which will continue Aura's OMI measurements with better ground resolution and precision. NASA plans to launch the Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument, which will observe ozone, nitrogen dioxide, sulfur dioxide, formaldehyde and aerosols over the United States, Canada and Mexico."Pollution is a global issue because it can travel long distances in the wind," said Anne Douglass, Aura project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "By using satellites, we can develop a valuable global inventory of pollutants and understand how air quality may be changing."For more on Aura's 10-year contribution to atmospheric chemistry research, visit:For more on TES, visit: For more on MLS, visit: NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.For more information about NASA's Earth science activities in 2014, visit:

Ozone Holes

July 13, 2014

https://www.sciencedaily.com/releases/2014/07/140713155504.htm

Australia drying caused by greenhouse gases, study shows

NOAA scientists have developed a new high-resolution climate model that shows southwestern Australia's long-term decline in fall and winter rainfall is caused by increases in humanmade greenhouse gas emissions and ozone depletion, according to research published today in

"This new high-resolution climate model is able to simulate regional-scale precipitation with considerably improved accuracy compared to previous generation models," said Tom Delworth, a research scientist at NOAA's Geophysical Fluid Dynamics Laboratory in Princeton, N.J., who helped develop the new model and is co-author of the paper. "This model is a major step forward in our effort to improve the prediction of regional climate change, particularly involving water resources."NOAA researchers conducted several climate simulations using this global climate model to study long-term changes in rainfall in various regions across the globe. One of the most striking signals of change emerged over Australia, where a long-term decline in fall and winter rainfall has been observed over parts of southern Australia. Simulating natural and humanmade climate drivers, scientists showed that the decline in rainfall is primarily a response to humanmade increases in greenhouse gases as well as a thinning of the ozone caused by humanmade aerosol emissions. Several natural causes were tested with the model, including volcano eruptions and changes in the sun's radiation. But none of these natural climate drivers reproduced the long-term observed drying, indicating this trend is due to human activity.Southern Australia's decline in rainfall began around 1970 and has increased over the last four decades. The model projects a continued decline in winter rainfall throughout the rest of the 21st century, with significant implications for regional water resources. The drying is most severe over southwest Australia where the model forecasts a 40 percent decline in average rainfall by the late 21st century."Predicting potential future changes in water resources, including drought, are an immense societal challenge," said Delworth. "This new climate model will help us more accurately and quickly provide resource planners with environmental intelligence at the regional level. The study of Australian drought helps to validate this new model, and thus builds confidence in this model for ongoing studies of North American drought."

Ozone Holes

July 10, 2014

https://www.sciencedaily.com/releases/2014/07/140710081215.htm

Polar zone ozone and UV exposure, under closer scrutiny than ever

The most-detailed atmospheric observation system available to date finds applications in forecasting ozone and UV emissions in the Arctic and Antarctic

Global changes, such as climate warming and stratospheric ozone depletion, are increasingly noticeable. Therefore, there is a need for scientists to have reliable information about atmospheric and stratospheric processes. Today, all developed countries have invested in sophisticated surveillance systems. Their data feeds into mathematical atmospheric models to provide sets of graphical, data and documentary information -- often available online -- used by climate scientists, weather forecasters, environmental agencies, authorities, etc. Europe specifically keeps data of unique and most valuable long-time Arctic and Antarctic ozone concentrations levels.Now, the EU funded project MACC-II has completed development and testing of a service that provides total surveillance of Earth's sensitive coats; namely the troposphere and the stratosphere. "It is generally acknowledged that the project can offer a previously unmatched bundle of very high quality data and model products," says Martin Schultz, group leader for atmospheric modelling, at the Research Centre Jülich, in Germany, who is involved in the project.Specifically, the project maintains and updates the historical record of stratospheric ozone using available satellite observations from 1979 until now. It has a special focus on the period 2003 to 2012; a time where ozone variations were quite dynamic. This service will become routinely operational from the spring of 2015. Indeed, it will be a component of the even larger initiative for an independent European Earth observation system, called Copernicus. In addition to the services developed in MACC II, this system includes land and marine monitoring, emergency management, border and maritime surveillance. It also gives access to climate change indicators such as temperature increase, sea level rise, and ice sheet melting.The project is now ready to acquire a wealth of data from satellites and ground stations all over the world in near real time; that is within one day or, at most, a week. Reliable mathematical models of atmospheric gases including greenhouse gases and ozone over the Polar regions will be run continuously. These regions react very sensitively on human-made chemicals, such as CFCs.In addition to analysing the current health of Earth's cushion of air, it will be able to forecast the development of ozone concentration for up to eight days in advance. The ozone concentration, in turn, influences the amount of UV radiation reaching Earth's surface. This will produce valuable information for political decisions on industrial emissions and for public health warnings.The challenges were to connect all the globally distributed databases and satellite data streams. And align the different data formats in a way that they could be fed into models. Models have now been developed and validated, and the final visualisation of the analyses and forecast products has been realised. Model evaluations were, for example, performed at the Norwegian Meteorological Institute, which has long expertise in trans-boundary long-range transport of air pollutants. "We are testing how good the project models perform by looking into their performance against true ground observations," Michael Gauss says. He is researcher at the Norwegian Meteorological Institute in Oslo.Pollutants can travel very long distances by air from industrial areas at lower latitudes up to the Polar regions, even diffusing on their way into the stratosphere.The project has been well received by international organisations such as the World Meteorological Organisation (WMO), based in Geneva, Switzerland. It is already a frequent user of the project's results. "We see this as a very useful, value adding project, because it combines satellite and meteorological data. And also uses ground based data to validate the models. This can give us information on geographical scales from the local up to the global," explains Geir Braathen, senior scientific officer at WMO.Specifically, Braathen produces WMO's ozone bulletins for the meteorological community and for the authorities interested in how the ozone holes over the Poles developed during a past season. They may give hints if political governance regarding the protection of the ozone layer had any effects. Braathen also uses the results from models of the US basedNational Aeronautics and Space Administration (NASA) and the National Oceanic and Atmospheric Administration (NOAA). "But the project will offer a much better ozone product, because an atmospheric chemistry model is included. With that you can follow the chemical change in ozone from day to day," Braathen says.The basic philosophy of the project is that all outcomes are freely available for policy makers and the public. In addition, the data and models are open for scientists who are not partner in the project. "We have used data from the project in our research and I believe this is an excellent European effort," says Aarne Männik, senior research fellow in numerical modelling of atmospheric dynamics at the Atmospheric Physics Laboratory of the University of Tartu, in Estonia. Ozone and UV data are of general interest for him as boundary conditions for his aerosol analyses in connection with forest fires and storm evolution. As an independent expert in this field he is a typical end user of the services provided by the project and encourages other scientists to use the project's data much more often.

Ozone Holes

July 8, 2014

https://www.sciencedaily.com/releases/2014/07/140708131821.htm

Record levels of solar ultraviolet on Earth's surface measured in South America

A team of researchers in the U.S. and Germany has measured the highest level of ultraviolet radiation ever recorded on Earth's surface. The extraordinary UV fluxes, observed in the Bolivian Andes only 1,500 miles from the equator, are far above those normally considered to be harmful to both terrestrial and aquatic life.

The results are being published in the open-access journal "These record-setting levels were not measured in Antarctica, where ozone holes have been a recurring problem for decades," says team leader Nathalie A. Cabrol of the SETI Institute and NASA Ames Research Center. "This is in the tropics, in an area where there are small towns and villages."The measurements were made in the southern hemisphere summer of 2003 and 2004, using instruments developed for the European Light Dosimeter Network (Eldonet). They were undertaken as Cabrol's team was investigating high altitude Andean lakes as part of an astrobiology study of Mars-like environments. Dosimeters were deployed on the summit of the towering Licancabur volcano (altitude: 5,917 meters) and at nearby Laguna Blanca (altitude 4,340 meters). The combination of a midday sun near the zenith, as well as the high elevation of these sites, produces higher irradiance levels because of naturally low ozone in such locations. But these intensities of short-wavelength UV-B radiation (280 -- 315 nm) are unprecedented."A UV index of 11 is considered extreme, and has reached up to 26 in nearby locations in recent years," notes Cabrol. "But on December 29, 2003, we measured an index of 43. If you're at a beach in the U.S., you might experience an index of 8 or 9 during the summer, intense enough to warrant protection. You simply do not want to be outside when the index reaches 30 or 40."The intense radiation coincided with other circumstances that may have increased the UV flux, including ozone depletion by increased aerosols from both seasonal storms and fires in the area. In addition, a large solar flare occurred just two weeks before the highest UV fluxes were registered. Ultraviolet spikes continued to occur -- albeit at lower intensity -- throughout the period of solar instability, and stopped thereafter. While the evidence linking the solar event to the record-breaking radiation is only circumstantial, particles from such flares are known to affect atmospheric chemistry and may have increased ozone depletion."While these events are not directly tied to climate change, they are sentinels of what could occur if ozone thins globally," Cabrol says. "The thinner and more unstable the ozone, the more prone we will be to this kind of event."High UV-B exposure negatively affects the entire biosphere, not just humans. It damages DNA, affects photosynthesis, and decreases the viability of eggs and larvae. For these reasons, it is important to keep a close watch on UV flux levels."While this unsettling record might be the result of a 'perfect storm' of events, it could happen again," says Cabrol, "because the factors that caused it are not rare. What we need is more monitoring of the ozone changes in these areas. These fluxes, which are comparable to those of early Mars, are occurring in a populated area."

Ozone Holes

June 30, 2014

https://www.sciencedaily.com/releases/2014/06/140630103148.htm

Green spaces in cities may increase erosion of building materials such as stone, concrete and steel

Green spaces in towns and cities need extra consideration as they may be damaging buildings in the area, according to new research from the Universities of Southampton and Surrey.

When organic chemicals from trees and vegetation mix with air pollutants the resulting corrosive gas can increase the erosion of building materials, including stone, concrete and steel.Southampton's Dr Abhishek Tiwary, who is based within the Centre for Environmental Sciences, and Dr Prashant Kumar, from the University of Surrey, found that heritage buildings, built from limestone and sandstone, are particularly at risk.Local authorities have been encouraged to invest in green spaces, which can reduce greenhouse gases, cut down exposure to pollution and provide mental health benefits. However, the effect on buildings from the mix of pollutants and organic chemicals has not been previously accounted for.The damage is mainly caused by ground level ozone, which is formed when volatile organic compounds given off by plants are broken down in sunlight and react with the common pollutant nitrogen dioxide.Using mathematical simulations, the research team investigated the effect of green vegetation on limestone and steel structures during different seasons."Species like sycamore maple and Douglas fir (both commonly found in cities) produced organic compounds which, combined with high levels of ground level ozone during the summer, heightened the concentration of ground level ozone," says Dr Tiwary."The effects of green infrastructure vary, depending on building material and the particular pollutant. Limestone, for example, found in the buildings like Westminster Abbey or the Houses of Parliament, is strongly eroded by increased levels of ground level ozone."Copper, zinc and carbon steel are also corroded by levels of air pollutants and local climatic conditions.Despite their damaging effect on buildings, the researchers recognise the importance of green areas in urban centres. "In the future, city planners should look into the species of vegetation they plant in green spaces," says Dr Tiwary. "Such consideration might improve the structural longevity of buildings of historical importance."

Ozone Holes

June 30, 2014

https://www.sciencedaily.com/releases/2014/06/140630094531.htm

Green planning needed to maintain city buildings

Green spaces in towns and cities need extra consideration as they may be damaging buildings in the area, according to new research from the Universities of Southampton and Surrey.

When organic chemicals from trees and vegetation mix with air pollutants the resulting corrosive gas can increase the erosion of building materials, including stone, concrete and steel.Southampton's Dr Abhishek Tiwary, who is based within the Centre for Environmental Sciences, and Dr Prashant Kumar, from the University of Surrey, found that heritage buildings, built from limestone and sandstone, are particularly at risk.Local authorities have been encouraged to invest in green spaces, which can reduce greenhouse gases, cut down exposure to pollution and provide mental health benefits. However, the effect on buildings from the mix of pollutants and organic chemicals has not been previously accounted for.The damage is mainly caused by ground level ozone, which is formed when volatile organic compounds given off by plants are broken down in sunlight and react with the common pollutant nitrogen dioxide.Using mathematical simulations, the research team investigated the effect of green vegetation on limestone and steel structures during different seasons."Species like sycamore maple and Douglas fir (both commonly found in cities) produced organic compounds which, combined with high levels of ground level ozone during the summer, heightened the concentration of ground level ozone," says Dr Tiwary."The effects of green infrastructure vary, depending on building material and the particular pollutant. Limestone, for example, found in the buildings like Westminster Abbey or the Houses of Parliament, is strongly eroded by increased levels of ground level ozone."Copper, zinc and carbon steel are also corroded by levels of air pollutants and local climatic conditions.Despite their damaging effect on buildings, the researchers recognise the importance of green areas in urban centres. "In the future, city planners should look into the species of vegetation they plant in green spaces," says Dr Tiwary. "Such consideration might improve the structural longevity of buildings of historical importance."

Ozone Holes

June 26, 2014

https://www.sciencedaily.com/releases/2014/06/140626115946.htm

New NASA images highlight U.S. air quality improvement

Anyone living in a major U.S. city for the past decade may have noticed a change in the air. The change is apparent in new NASA satellite images unveiled this week that demonstrate the reduction of air pollution across the country.

After ten years in orbit, the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite has been in orbit sufficiently long to show that people in major U.S. cities are breathing less nitrogen dioxide -- a yellow-brown gas that can cause respiratory problems.Nitrogen dioxide is one of the six common pollutants regulated by the U.S. Environmental Protection Agency (EPA) to protect human health. Alone it can impact the respiratory system, but it also contributes to the formation of other pollutants including ground-level ozone and particulates, which also carry adverse health effects. The gas is produced primarily during the combustion of gasoline in vehicle engines and coal in power plants. It's also a good proxy for the presence of air pollution in general.Air pollution has decreased even though population and the number of cars on the roads have increased. The shift is the result of regulations, technology improvements and economic changes, scientists say.In fact, about 142 million people still lived in areas in the United States with unhealthy levels of air pollution, according to the EPA. Also, high levels of air pollution remain an issue in many other parts of the world, according to the global view from satellites."While our air quality has certainly improved over the last few decades, there is still work to do -- ozone and particulate matter are still problems," said Bryan Duncan, an atmospheric scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland.Decision makers and regulatory agencies like EPA have long relied on data from ground sites to inform air quality science and forecasts. NASA, while not directly involved with regulation or making forecasts, provides a consistent, global, space-based view -- not possible from any other source -- of when and where air pollution occurs.Another ongoing effort by NASA to study air quality is Discover-AQ, a multi-year airborne mission flying this summer in Denver to learn more about how the wide range of air pollutants viewed from satellites relates to what's happening close to the ground where people live and breathe. The mission flew previously in 2011 over Baltimore, Maryland and Washington, D.C.; in 2013 over the San Joaquin Valley, California; and in 2013 over Houston, Texas."You can't control what you don't measure," said Russ Dickerson of the University of Maryland, College Park, and member of the NASA Air Quality Applied Sciences Team -- created in 2011 by the NASA Applied Sciences Program to serve the needs of U.S. air quality management through the use of Earth Science satellite data, suborbital, and models. "NASA measurements of air quality have value to the people with the authority to control emissions and develop policy."The new NASA images also take a close up look at the Ohio River Valley, Northeast Corridor, and some populous U.S. cities. They show how nitrogen dioxide concentrations during spring and summer months, averaged from 2005-2007, compare to the average from 2009-2011.Measurements of nitrogen dioxide from OMI depict the concentration of the gas throughout a column of air in the troposphere, Earth's lowest atmospheric layer. The images are color-coded: Blue and green denote lower concentrations and orange and red denote higher concentrations, ranging from 1x10Images were composed by NASA's Scientific Visualization Studio based on data and input provided by atmospheric scientists Yasuko Yoshida, Lok Lamsal, and Bryan Duncan, all of NASA's Goddard Space Flight Center in Greenbelt, Maryland.

Ozone Holes

June 3, 2014

https://www.sciencedaily.com/releases/2014/06/140603193902.htm

Count of new CFCs in the atmosphere rises from four to seven

Scientists at the University of East Anglia have found two new chlorofluorocarbons (CFCs) and one new hydrochlorofluorocarbon (HCFC) in the atmosphere.

The research, published in the journal Scientists made the discovery by comparing today's air samples with air collected between 1978 and 2012 in unpolluted Tasmania, and samples taken during aircraft flights.Measurements show that all but one of the new gases have been released into the atmosphere in recent years.Dr Johannes Laube, from UEA's school of Environmental Sciences, said: "Two of the gases that we found earlier in the year were particularly worrying because they were still accumulating significantly up until 2012. Emission increases of this scale have not been seen for any other CFCs since controls were introduced during the 1990s, but they are nowhere near peak CFC emissions of the 1980s."We have now identified another two CFCs and one HCFC, although these have much lower concentrations than the previous ones. It is therefore unlikely that they will pose a threat to the ozone layer. They do however strengthen our argument that there are many more gases out there and the sum of them may well have an impact."Corinna Kloss, who undertook the research while at UEA, now at the Jülich Research Centre in Germany, said: "All seven gases were only around in the atmosphere in very small amounts before the 1980s, with four not present at all before the 1960s, which suggests they are human-made. Where these new gases are coming from should be investigated. Possible sources include industrial solvents, feedstock chemicals and refrigerants."CFCs are the main cause of the hole in the ozone layer over Antarctica. Laws to reduce and phase out CFCs came into force in 1989, followed by a total ban in 2010. This has resulted in successfully reducing the production of many of these compounds on a global scale.

Ozone Holes

May 9, 2014

https://www.sciencedaily.com/releases/2014/05/140509172545.htm

Toxicologists outline key health and environmental concerns associated with hydraulic fracturing

Since the rise in the use of hydraulic fracturing of shale to produce natural gas and oil, scientists, politicians, industrialists, and others have debated the merits and detractions of the practice. In a newly published paper in

"Toxicology is the study of the effects of chemical, physical, or biological agents on living organisms and the environment. As such, toxicologists should be at the forefront of discussions of hydraulic fracturing," says Society of Toxicology President Norbert E. Kaminski, PhD. "We can provide information on the potential toxicity of the chemical and physical agents associated with the process, individually and in combination."In "The Role of Toxicological Science in Meeting the Challenges and Opportunities of Hydraulic Fracturing" Bernard D. Goldstein, et al, identify a series of potential pathways of contamination and toxicological effects associated with hydraulic fracturing that should and are being explored by researchers:

Ozone Holes

May 7, 2014

https://www.sciencedaily.com/releases/2014/05/140507142847.htm

Airborne measurements confirm leaks from oil and gas operations

During two days of intensive airborne measurements, oil and gas operations in Colorado's Front Range leaked nearly three times as much methane, a greenhouse gas, as predicted based on inventory estimates, and seven times as much benzene, a regulated air toxic. Emissions of other chemicals that contribute to summertime ozone pollution were about twice as high as estimates, according to the new paper, accepted for publication in the American Geophysical Union's

"These discrepancies are substantial," said lead author Gabrielle Petron, an atmospheric scientist with the Cooperative Institute for Research in Environmental Sciences, a joint institute of the University of Colorado Boulder and the National Oceanic and Atmospheric Administration. "Emission estimates or 'inventories' are the primary tool that policy makers and regulators use to evaluate air quality and climate impacts of various sources, including oil and gas sources. If they're off, it's important to know."The new paper provides independent confirmation of findings from research performed from 2008-2010, also by Petron and her colleagues, on the magnitude of air pollutant emissions from oil and gas activities in northeastern Colorado. In the earlier study, the team used a mobile laboratory -- sophisticated chemical detection instruments packed into a car -- and an instrumented NOAA tall tower near Erie, Colorado, to measure atmospheric concentrations of several chemicals downwind of various sources, including oil and gas equipment, landfills and animal feedlots.Back then, the scientists determined that methane emissions from oil and gas activities in the region were likely about twice as high as estimates from state and federal agencies, and benzene emissions were several times higher. In 2008, northeastern Colorado's Weld County had about 14,000 operating oil and gas wells, all located in a geological formation called the Denver-Julesburg Basin.In May 2012, when measurements for the new analysis were collected, there were about 24,000 active oil and gas wells in Weld County. The new work relied on a different technique, too, called mass-balance. In 2012, Petron and her colleagues contracted with a small aircraft to measure the concentrations of methane and other chemicals in the air downwind and upwind of the Denver-Julesburg Basin. On the ground, NOAA wind profilers near Platteville and Greeley tracked around-the-clock wind speed and wind direction.On two days in May 2012, conditions were ideal for mass-balance work. Petron and her team calculated that 26 metric tons of methane were emitted hourly in a region centered on Weld County. To estimate the fraction from oil and gas activities, the authors subtracted inventory estimates of methane emissions from other sources, including animal feedlots, landfills and wastewater treatment plants. Petron and her team found that during those two days, oil and gas operations in the Denver-Julesburg Basin emitted about 19 metric tons of methane per hour, 75 percent of the total methane emissions. That's about three times as large as an hourly average estimate for oil and gas operations based on Environmental Protection Agency's (EPA's) Greenhouse Gas Reporting Program (itself based on industry-reported emissions).Petron and her colleagues combined information from the mass-balance technique and detailed chemical analysis of air samples in the laboratory to come up with emissions estimates for volatile organic compounds, a class of chemicals that contributes to ozone pollution; and benzene, an air toxic.Benzene emissions from oil and gas activities reported in the paper are significantly higher than state estimates: about 380 pounds (173 kilograms) per hour, compared with a state estimate of about 50 pounds (25 kilograms) per hour. Car and truck tailpipes are a known source of the toxic chemical; the new results suggest that oil and gas operations may also be a significant source.Oil-and-gas-related emissions for a subset of volatile organic compounds (VOCs), which can contribute to ground-level ozone pollution, were about 25 metric tons per hour, compared to the state inventory, which amounts to 13.1 tons. Ozone at high levels can harm people's lungs and damage crops and other plants; the northern Front Range of Colorado has been out of compliance with federal health-based 8-hour ozone standards since 2007, according to the EPA. Another CIRES- and NOAA-led paper published last year showed that oil and natural gas activities were responsible for about half of the contributions of VOCs to ozone formation in northeastern Colorado.This summer, dozens of atmospheric scientists from NASA, the National Center for Atmospheric Research, NOAA, CIRES and other will gather in the Front Range, to participate in an intensive study of the region's atmosphere, said NCAR scientist Gabriele Pfister. With research aircraft, balloon-borne measurements, mobile laboratories and other ground-based equipment, the scientists plan to further characterize the emissions of many possible sources, including motor vehicles, power plants, industrial activities, agriculture, wildfires and transported pollution."This summer's field experiment will provide us the information we need to understand all the key processes that contribute to air pollution in the Front Range," Pfister said.

Ozone Holes

May 5, 2014

https://www.sciencedaily.com/releases/2014/05/140505130528.htm

Climate change threatens to worsen U.S. ozone pollution

Ozone pollution across the continental United States will become far more difficult to keep in check as temperatures rise, according to new research led by the National Center for Atmospheric Research (NCAR). The detailed study shows that Americans face the risk of a 70 percent increase in unhealthy summertime ozone levels by 2050.

This is because warmer temperatures and other changes in the atmosphere related to a changing climate, including higher atmospheric levels of methane, spur chemical reactions that lead to ozone.Unless emissions of specific pollutants that are associated with the formation of ozone are sharply cut, almost all of the continental United States will experience at least a few days with unhealthy air during the summers, the research shows. Heavily polluted locations in parts of the East, Midwest, and West Coast in which ozone already frequently exceeds recommended levels could face unhealthy air during most of the summer."It doesn't matter where you are in the United States -- climate change has the potential to make your air worse," said NCAR scientist Gabriele Pfister, the lead author of the new study. "A warming planet doesn't just mean rising temperatures, it also means risking more summertime pollution and the health impacts that come with it."However, the research also showed that a sharp reduction in the emissions of certain pollutants would lead to dramatically decreased levels of ozone even as temperatures warm.The detailed research is one of the first of its type to be conducted with new, highly advanced geoscience supercomputing capabilities. It will be published online this week in the The work was funded by the National Science Foundation (NSF), which is NCAR's sponsor, and the U.S. Department of Energy. In addition to NCAR, the study co-authors are from the Pacific Northwest National Laboratory; University of Colorado, Boulder; and North-West University in South Africa.Ozone pollution is not emitted directly, but instead forms as a result of chemical reactions that take place between nitrogen oxides and volatile organic compounds in the presence of sunlight. These gases come from human activities such as combustion of coal and oil as well as natural sources such as emissions from plants.Unlike ozone in the stratosphere, which benefits life on Earth by blocking ultraviolet radiation from the Sun, ground-level ozone can trigger a number of health problems. These range from coughing and throat irritation to more serious problems, including aggravation of asthma, bronchitis, and emphysema. Even short periods of unhealthy ozone levels can cause local death rates to rise. Ozone pollution also damages crops and other plants.To examine the impacts of climate change on ozone pollution, Pfister and her colleagues looked at two scenarios. In one, emissions of nitrogen oxides and volatile organic compounds from human activities would continue at current levels through 2050. In the other, emissions would be cut by 60-70 percent. Both scenarios assumed continued greenhouse gas emissions with significant warming.The researchers found that, if emissions continue at present-day rates, the number of eight-hour periods in which ozone would exceed 75 parts per billion (ppb) would jump by 70 percent on average across the United States by 2050. The 75 ppb level over eight hours is the threshold that is considered unhealthy by the Environmental Protection Agency. (The agency is considering tightening the standard to a value between 65 and 70 ppb over eight hours.)Overall, the study found that, 90 percent of the time, ozone levels would range from 30 to 87 ppb in 2050 compared with an estimated 31 to 79 ppb in the present. Although the range itself shifts only slightly, the result is a much larger number of days above the threshold now considered unhealthy.There are three primary reasons for the increase in ozone with climate change:In the second scenario, Pfister and her colleagues found that sharp reductions in nitrogen oxides and volatile organic compounds could reduce ozone pollution even as the climate warms. In fact, 90 percent of the time, ozone levels would range from 27 to 55 ppb. The number of instances when ozone pollution would exceed the 75 ppb level dropped to less than 1 percent of current cases."Our work confirms that reducing emissions of ozone precursors would have an enormous effect on the air we all breathe," Pfister said.Pfister and a nationwide scientific team expect to learn more about the sources, chemistry, and movement of air pollutants this summer when they launch a major field experiment known as FRAPPÉ along Colorado's Front Range.The new study was among the first conducted on the new 1.5-petaflop Yellowstone supercomputer. The IBM system, operated by NCAR and supported by funding from the NSF and the University of Wyoming, is one of the world's most powerful computers specifically dedicated to research in the atmospheric and related sciences.Thanks to its computing power, the scientists were able to simulate pollution levels hour by hour for 39 hypothetical summers. This allowed the team to account for year-to-year variations in meteorological conditions, such as hot and dry vs. cool and wet, thereby getting a more detailed and statistically significant picture of future pollution levels.To simulate the interplay of global climate with regional pollution conditions, the scientists turned to two of the world's leading atmospheric models, both based at NCAR and developed through broad collaborations with the atmospheric science community. They used the Community Earth System Model, funded primarily by the Department of Energy and NSF, to simulate global climate as well as atmospheric chemistry conditions. They also used an air chemistry version of the multiagency Weather Research and Forecasting model to obtain a more detailed picture of regional ozone levels.Even with Yellowstone's advanced computing speed, it took months to complete the complex simulations."This research would not have been possible even just a couple of years ago," said Pfister. "Without the new computing power made possible by Yellowstone, you cannot depict the necessary detail of future changes in air chemistry over small areas, including the urban centers where most Americans live."

Ozone Holes

April 28, 2014

https://www.sciencedaily.com/releases/2014/04/140428143315.htm

Ozone levels drop 20 percent with switch from ethanol to gasoline

A Northwestern University study by an economist and a chemist reports that when fuel prices drove residents of São Paulo, Brazil, to mostly switch from ethanol to gasoline in their flexible-fuel vehicles, local ozone levels dropped 20 percent. At the same time, nitric oxide and carbon monoxide concentrations tended to go up.

The four-year study is the first real-world trial looking at the effects of human behavior at the pump on urban air pollution. This empirical analysis of atmospheric pollutants, traffic congestion, consumer choice of fuel and meteorological conditions provides an important tool for studying other large cities, such as Chicago, New York, London and Beijing. Previous studies mainly have consisted of computer simulations of atmospheric chemical reactions based on tailpipe emissions studies."Individuals often don't realize it, but in the aggregate, you can have a real impact on the environment," said Alberto Salvo, formerly with Northwestern's Kellogg School of Management and now an associate professor of economics at the National University of Singapore. "In São Paulo, there were more than a million cars switching from ethanol to gasoline in the same season, and we found that ozone levels went down. We didn't expect this, but it is a precise result."Salvo teamed up with chemist Franz M. Geiger to help him tease the air quality picture out of the highly complex chemistry using statistical methods. The results of their study will be published April 28 in the journal Salvo and Geiger used fuel sales data and 14,000 consumer surveys to predict the magnitude of the fuel shift from ethanol to gasoline and back over the course of 30 months. They next determined the change in pollutant concentrations based on the predicted fuel mix, meteorology data and traffic levels across 600 miles of roads and discovered that ozone levels decreased significantly relative to the rise of gasoline usage.Having lived in São Paulo, Salvo realized the city offered the best possible "natural laboratory" -- a real-life situation as opposed to hypothetical -- to study consumer behavior and its impact on air quality using big data. The air-monitoring network in the megacity is superb, and the weather is moderate, with temperatures fluctuating little throughout the year.During two episodes of high sugar prices in 2010 and again in 2011, the price of ethanol increased, causing consumers to switch their fuel usage to gasoline. (Brazil is a big producer of sugar, and the country's ethanol is made from sugar cane.) These two episodes provided the perfect situation for Salvo and Geiger's study."São Paulo was the place to do this initial study because consumers can and do switch between fuels for reasons unrelated to air quality, roads are gridlocked, and there is so much good data available to researchers," Salvo said.São Paulo has the world's largest flexible-fuel vehicle fleet, with cars that can run on all gasoline, all ethanol or some mix of the two. Gasoline prices in Brazil are controlled by the government, and the domestic sugar price -- and therefore the domestic price of ethanol -- is determined by the world sugar price.Scientific studies using big data can help take policymakers a long way in figuring out how to mitigate air pollution given local conditions, the researchers said. Effects of fuel usage will depend on local atmospheric composition, such as fine particle pollutants."Ozone and nitric oxide are both contributors to urban smog, so depending on how well a city is able to mitigate air pollution, ethanol may not be the 'green fuel' that it is often called," said Geiger, professor of chemistry in the Weinberg College of Arts and Sciences. He and Salvo are now analyzing how the concentration of other air pollutants in São Paulo, specifically fine particles, change in response to the choices of motorists in the city.Geiger cautioned that their results are valid only for the subtropical city of São Paulo, but the researchers' interdisciplinary approach can be used to examine more complicated city situations. Their study shows how pollution control requires a team that bridges atmospheric science and engineering, economics and statistics."This work allows us to start thinking about the urban metabolism of Chicago, which is an emerging megacity surrounded by 'corn country,'" Geiger said. "Ethanol from corn is a particularly intriguing option for future, possibly more competitive, energy markets. It's an area we need to watch.""It is a credit to the interdisciplinary process that Franz now is talking like an economist," Salvo said with a grin.A grant for high-risk research from the Institute for Sustainability and Energy at Northwestern (ISEN) got Salvo started with his work, but it was when Mark Ratner, ISEN co-director and a chemist, introduced Salvo to Geiger that the study was really underway. The unusual study needed both a social scientist and a chemist to be successful."Without ISEN, this work would never have happened -- no way," Geiger said.Geiger and Salvo plan to collaborate with Aaron Packman, professor of civil and environmental engineering at the McCormick School of Engineering and Applied Science, on studying urban metabolites in Chicago. Specifically, the group plans to use Cook County's air monitoring network, traffic data and meteorological data to learn how the concentration of air pollutants in the city may change under future -- and most likely more congested -- traffic scenarios.

Ozone Holes

April 15, 2014

https://www.sciencedaily.com/releases/2014/04/140415094141.htm

New sensor improves the level of efficiency in detecting ozone

Researchers from the Universitat Jaume I in Castelló, the São Paulo State University in Brasil and the Aix-Marseille University in France have developed a more effective ozone sensor than the ones used so far. The new sensor detects this gas faster and in lower amounts. Ozone is present in the atmosphere and it plays a significant role in the protection of living beings because it absorbs the ultraviolet radiation from the sun. However, the exposure to certain concentrations of this gas may cause health problems, such as headache, burning and irritation of the eyes and respiratory system problems; that is why it is relevant to detect its presence effectively.

This sensor ―developed by researchers from the three universities― is based on silver tungstate nanofilaments. The study ―published by the magazine The professor of Physical Chemistry at the Universitat Jaume I, Juan M. Andrés, highlights the importance of detecting the presence of ozone gas. "Despite of being a gas that offers several beneficial applications, such as the protection against harmful solar radiation or its use for water treatment, in certain concentrations it can be dangerous for health." In this sense, the World Health Organisation recommends avoiding the exposure to ozone gas above 120 ppb (parts per billion). The researcher from the Jaume I explains that with the new sensor "a fast response, as well as a very short recovering time, has been observed. It makes its properties even better than traditional sensors based in tin dioxide, tungsten trioxide or indium oxide."The participation of the UJI lies within one of the lines of research in collaboration with the Instituto Nacional de Ciência e Tecnologia dos Materiais em Nanotecnologia(INCTMN), led by the lecturer Elsón Longo, the doctor Lourdes Gracia ―with a postdoctoral contract in the Department of Physical and Analytical Chemistry at the UJI― and the doctor by the UJI Patricio González-Navarrete, who is currently doing an Alexander von Humboldt postdoctoral stay at the Technische Universität in Berlín (Germany). The researchers at the UJI have developed and applied several methods and techniques of theoretical and computational chemistry, that are based on quantum mechanics, in order to understand and rationalize these nanomaterials properties; not only as gas sensors, but also as bactericides and luminescent sensors to guide the experimental proofs to synthesize new nanomaterials with specific technological applications. This project is a follow-up from the ones previously published in this research field.

Ozone Holes

April 14, 2014

https://www.sciencedaily.com/releases/2014/04/140414154446.htm

Plugging an ozone hole: Extreme Antarctic ozone holes have not been replicated in Arctic

Since the discovery of the Antarctic ozone hole, scientists, policymakers, and the public have wondered whether we might someday see a similarly extreme depletion of ozone over the Arctic.

But a new MIT study finds some cause for optimism: Ozone levels in the Arctic haven't yet sunk to the extreme lows seen in Antarctica, in part because international efforts to limit ozone-depleting chemicals have been successful."While there is certainly some depletion of Arctic ozone, the extremes of Antarctica so far are very different from what we find in the Arctic, even in the coldest years," says Susan Solomon, the Ellen Swallow Richards Professor of Atmospheric Chemistry and Climate Science at MIT, and lead author of a paper published this week in the Frigid temperatures can spur ozone loss because they create prime conditions for the formation of polar stratospheric clouds. When sunlight hits these clouds, it sparks a reaction between chlorine from chlorofluorocarbons (CFCs), human-made chemicals once used for refrigerants, foam blowing, and other applications -- ultimately destroying ozone.After the ozone-attacking properties of CFCs were discovered in the 1980s, countries across the world agreed to phase out their use as part of the 1987 Montreal Protocol treaty. While CFCs are no longer in use, those emitted years ago remain in the atmosphere. As a result, atmospheric concentrations have peaked and are now slowly declining, but it will be several decades before CFCs are totally eliminated from the environment -- meaning there is still some risk of ozone depletion caused by CFCs."It's really a success story of science and policy, where the right things were done just in time to avoid broader environmental damage," says Solomon, who made some of the first measurements in Antarctica that pointed toward CFCs as the primary cause of the ozone hole.To obtain their findings, the researchers used balloon and satellite data from the heart of the ozone layer over both polar regions. They found that Arctic ozone levels did drop significantly during an extended period of unusual cold in the spring of 2011. While this dip did depress ozone levels, the decrease was nowhere near as drastic as the nearly complete loss of ozone in the heart of the layer seen in many years in Antarctica.The MIT team's work also helps to show chemical reasons for the differences, demonstrating that ozone loss in Antarctica is closely associated with reduced levels of nitric acid in air that is colder than that in the Arctic."We'll continue to have cold years with extreme Antarctic ozone holes for a long time to come," Solomon says. "We can't be sure that there will never be extreme Arctic ozone losses in an unusually cold future year, but so far, so good -- and that's good news."The paper is the first to use observational evidence to confirm the chemical processes in polar stratospheric clouds that lead to ozone loss, says Brian Toon, a professor of atmospheric and oceanic sciences at the University of Colorado at Boulder and an expert on stratospheric ozone loss. Previous studies have used computer models or theories to explain the connection between nitric acid in these clouds and ozone depletion."It is an excellent example of the relatively rare paper that is clever and insightful," says Toon, who was not involved in this most recent study. "[It] goes beyond complex computer calculations to demonstrate from observations an important process occurring in the atmosphere."

Ozone Holes

April 11, 2014

https://www.sciencedaily.com/releases/2014/04/140411091941.htm

NASA simulation portrays ozone intrusions from aloft

Outdoor enthusiasts in Colorado's Front Range are occasionally rewarded with remarkable visibility brought about by dry, clear air and wind. But it's what people in the mountainous U.S. West can't see in conditions like this -- ozone plunging down to the ground from high in the stratosphere, the second layer of the atmosphere -- that has attracted the interest of NASA scientists, university scientists and air quality managers.

Ozone in the stratosphere, located on average 10 to 48 kilometers (6 to 30 miles) above the ground, typically stays in the stratosphere. Not on days like April 6, 2012.On that day, a fast-moving area of low pressure moved northeast across states in the Western U.S., clipping western and northern Colorado. Ozone-rich stratospheric air descended, folding into tropospheric air near the ground. Winds took hold of the air mass and pushed it in all directions, bringing stratospheric ozone to the ground in Colorado and along the Northern Front Range. The event, called a stratospheric ozone intrusion, raised ground-level ozone concentrations in some areas to potentially unhealthy levels. Watch the intrusion unfold in a new NASA simulation of the event.Ozone high in the atmosphere, in the stratosphere, forms naturally when sunlight mingles with oxygen molecules to form the well-known "layer" that protects life on Earth from the sun's harmful ultraviolet rays. That's in contrast to ozone near the ground, in the troposphere, which forms from complex reactions involving chemicals emitted from industrial processes, vehicle exhaust, and other byproducts of fossil fuel combustion. Ozone at ground level can damage lung tissue and pose an immediate threat to sensitive groups such as people with asthma.For this reason, the Clean Air Act requires the U.S. Environmental Protection Agency to set a threshold for ground-level ozone, as outlined in the National Ambient Air Quality Standards. States that exceed this threshold can be fined, although the EPA can grant exceptions for natural events or those proven to be beyond reasonable control.That's why ozone intrusions are on the minds of air quality managers like Patrick Reddy, lead forecast meteorologist at Colorado's Department of Public Health and Environment in Denver, Colo. Reddy co-leads the EPA Stratospheric Intrusion Work Group, tasked to identify ozone intrusion events and collect input for improved analysis.The state of Colorado flagged the concentrations associated with the April 6 event as possibly exceeding the EPA's allowable threshold. Now it's up to Reddy and colleagues to determine if the intrusion on April 6 is a viable candidate for the preparation of documentation to be classified as an exceptional event."We need to use the best science that we can to demonstrate conclusively that 'but for' this intrusion there would not have been an exceedence," Reddy said.Reddy says it's fairly obvious when a stratospheric ozone intrusion has occurred, based on signatures in satellite data, air quality monitoring stations and meteorological data. For example, low water vapor, wind and high ozone at remote locations are often characteristic of stratospheric air.Evidence of the intrusions, however, doesn't show up in the models currently used by air quality managers. Many of those models assume ozone moves from the stratosphere to the troposphere at a constant, average rate. This fails to capture the episodic intrusion events.Meiyun Lin, an atmospheric scientist at Princeton University and NOAA's Geophysical Fluid Dynamics Laboratory (GFDL) in Princeton, New Jersey, set out to better quantify the impact of stratospheric ozone intrusions. Lin and colleagues used satellite and meteorological observations alongside a global chemistry-climate model to simulate intrusions in high-resolution.Like the pixels in a photograph, the resolution of a model refers to the size of three-dimensional boxes of atmosphere. Models simulate the chemistry and atmospheric processes inside each box. For perspective, a model with 200-kilometer (124-mile) resolution is typical of today's high-end climate models, and 25-kilometer (16-mile) resolution is typical of high-end weather forecasts."We absolutely need to use a model with a grid size at least as small as, or smaller than, 50-by-50 kilometers (31-by-31 miles) to look at where and when the stratospheric air reaches the surface," Lin said.Lin's analysis, based on a GFDL model with 50-kilometer (31-mile) resolution, suggests that the impact on ground level ozone in the U.S. West from springtime intrusion events is two to three times greater than previously estimated. The study was published October 2012 in Steven Pawson and Eric Nielsen, atmospheric scientists at NASA's Goddard Space Flight Center in Greenbelt, Md., are also in pursuit of improved model simulations of stratospheric ozone intrusions. The team set out to see if the Goddard Earth Observing System Model, Version 5 (GEOS-5) Chemistry-Climate Model could replicate stratospheric intrusions at 25-kilometer (16-mile) resolution.They show that indeed, the model could replicate small-scale features, including finger-like filaments, within the apron of ozone-rich stratospheric air that descended over Colorado on April 6, 2012."High-resolution modeling is giving us the capability to examine these events comprehensively for the first time," Nielsen said.High-resolution models are possible due to computing power now capable of simulating the chemistry and movement of gasses and pollutants around the atmosphere and calculating their interactions. The addition of chemistry to these models, however, is not without a computational cost. For example, a weather forecast that takes about one hour of computational time would take five hours to run at the same resolution with the chemistry included."For a long time people thought excluding stratospheric chemistry was a reasonable approximation to make," said Lesley Ott, an atmospheric scientist at NASA Goddard. "But recent work has shown that you really need to consider what the stratosphere is doing. It's not just something you can totally ignore, despite the fact that it's more computationally intensive."Atmospheric measurements from the ground and from aircraft suggest the higher resolution models are on track. In June and July 2011, NASA aircraft flew at low altitude over the Baltimore-Washington area as part of DISCOVER-AQ, a NASA airborne campaign to study urban air quality. Comparing data from the aircraft with the model output, Ott says the models performed well.Scientists already know that intrusions reaching surface air are more frequent in spring and early summer, when chemistry and weather conditions are more favorable for such events. Also, intrusions are more likely to affect mountainous regions in the U.S. West simply because land at elevation is closer to the stratosphere.The next step is to find out how the frequency of intrusions changes from year to year and what controls its variability. "This is really the first time that our models are giving us the chance to try to answer those questions," Ott said.Reddy, too, looks forward to seeing if the models can streamline reporting and forecasting efforts. "The nice thing about the new model products is that they could help us potentially do a better job forecasting these events and documenting what happened for those events that we want to submit to the EPA," he said.The models could also help Reddy as his agency works to refine and expand its services. Models that could more accurately focus the timing and scale of intrusion effects would enhance the state's ability to issue advisories that better target affected populations.Does that mean that spring skiers will have an additional forecast to consider before heading to the slopes?"In the West, don't be surprised if on a clean-looking, windy day in spring there's an ozone health advisory," Reddy said.As for Bryan Duncan, an atmospheric scientist at NASA Goddard, "It wouldn't stop me from enjoying the powder conditions."

Ozone Holes

April 4, 2014

https://www.sciencedaily.com/releases/2014/04/140404092931.htm

'Like a giant elevator to the stratosphere:' Newly discovered atmospheric layer may impact Earth's climate

An international team of researchers headed by Potsdam scientist Dr. Markus Rex from the Alfred Wegener Institute has discovered a previously unknown atmospheric phenomenon over the South Seas. Over the tropical West Pacific there is a natural, invisible hole extending over several thousand kilometres in a layer that prevents transport of most of the natural and humanmade substances into the stratosphere by virtue of its chemical composition. Like in a giant elevator, many chemical compounds emitted at the ground pass thus unfiltered through this so-called "detergent layer" of the atmosphere. Scientists call it the "OH shield." The newly discovered phenomenon over the South Seas boosts ozone depletion in the polar regions and could have a significant influence on the future climate of Earth -- also because of rising air pollution in South East Asia.

At first Dr. Markus Rex suspected a series of flawed measurements. In October 2009 the atmospheric physicist from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) was on board the German research vessel "Sonne" to measure trace substances in the atmosphere in the tropical West Pacific. Tried and tested a thousand times over, the ozone probes he sent up into the tropical sky with a research balloon every 400 kilometres reported -- nothing. Or to be more accurate: almost nothing. The ozone concentrations in his measurements remained nearly constantly below the detection limit of approx. 10 ppbv in the entire vertical range from the surface of Earth to an altitude of around 15 kilometres. Normally ozone concentrations in this part of the atmosphere are three to ten times higher. (One part of ozone per billion by volume (ppbv) means there is one ozone molecule for every billion air molecules.)Although low values at an altitude of around 15 kilometres were known from earlier measurements in the peripheral area of the tropical West Pacific, the complete absence of ozone at all heights was surprising. However, after a short period of doubt and various tests of the instruments it dawned on the worldwide recognized ozone specialist that he might be onto a phenomenon yet unknown to science. A few research years later and after the involvement of other colleagues came confirmation: Markus Rex and his team on board the "Sonne" had tracked down a giant natural hole over the tropical South Seas, situated in a special layer of the lower atmosphere known as the "OH shield." The research results on the newly discovered OH minimum will be published soon in the journal "Even though the sky appears to be an extensively uniform space for most people, it is composed of chemically and physically very different layers," Markus Rex explains the complex makeup of the atmosphere. The air layers near the ground contain hundreds or even thousands of chemical compounds. This is why winter and spring, mountains and sea, city and forests all have a distinct smell. The great majority of these substances are broken down into water-soluble compounds in the lower kilometres of the atmosphere and are subsequently washed out by rain. Since these processes require the presence of a certain chemical substance, the so called hydroxyl (=OH) radical, this part of the atmosphere is called the "OH shield." It acts like a huge atmospheric washing machine in which OH is the detergent.The OH shield is part of the troposphere, as the lower part of the atmosphere is called. "Only a few, extremely long-lived compounds manage to make their way through the OH shield," says Rex, "then they also get through the tropopause and enter the stratosphere." Tropopause refers to the boundary layer between the troposphere and the next atmospheric layer above it, the stratosphere. Particularly substances that enter the stratosphere unfold a global impact. The reason for this is that once they have reached the stratosphere, their degradation products remain up there for many years and spread over the entire globe.Extremely long-lived chemical compounds find their way to the stratosphere, even where the OH shield is intact. These include methane, nitrous oxide ("laughing gas"), halons, methyl bromide and chlorofluorocarbons (CFCs), which are notorious as "ozone killers" because they play a major role in ozone depletion in the polar regions.After many years of research scientists now understand the complicated process of stratospheric ozone depletion very well. "Nevertheless measured ozone depletion rates were often quite a bit larger than theoretically calculated in our models," Markus Rex points out a long unsolved problem of atmospheric research. "Through the discovery of the OH hole over the tropical West Pacific we have now presumably made a contribution to solving this puzzle." And at the same time discovered a phenomenon that raises a number of new questions for climate policy. Researchers are now tackling these questions in a new research project funded by the EU with around 9 million euros, i.e. "StratoClim," which is coordinated by the Alfred Wegener Institute. Within this project a new monitoring station will be established in the tropical Westpacific, together with the Institute of Environmental Physics at the University of Bremen."We have to realise," reminds the Potsdam atmospheric physicist, "that chemical compounds which enter the stratosphere always have a global impact." Thanks to the OH hole that the researchers discovered over the tropical Pacific, greater amounts of brominated hydrocarbons can reach the stratosphere than in other parts of the world. Although their ascent takes place over the tropical West Pacific, these compounds amplify ozone depletion in the polar regions. Since scientists identified this phenomenon and took it into account in the modelling of stratospheric ozone depletion, their models have corresponded excellently with the actually measured data.However, it is not only brominated hydrocarbons that enter the stratosphere over the tropical West Pacific. "You can imagine this region as a giant elevator to the stratosphere," states Markus Rex using an apt comparison. Other substances, too, rise here to a yet unknown extent while they are intercepted to a larger extent in the OH shield elsewhere on the globe. One example is sulphur dioxide, which has a significant impact on the climate.Sulphur particles in the stratosphere reflect sunlight and therefore act antagonistically to atmospheric greenhouse gases like COIf one takes into account that sulphur dioxide may also reach the stratosphere via the OH hole over the tropical West Pacific, it quickly becomes obvious that the atmospheric elevator over the South Seas not only boosts ozone depletion, but may influence the climate of the entire Earth. In fact, the aerosol layer in the stratosphere, which is also composed of sulphur particles, seems to have become thicker in recent years. Researchers do not know yet whether there is a connection here.But wouldn't it be a stroke of luck if air pollutants from South East Asia were able to mitigate climate warming? "By no means," Markus Rex vigorously shakes his head. "The OH hole over the South Seas is above all further evidence of how complex climate processes are. And we are still a long way off from being in a position to assess the consequences of increased sulphur input into the stratosphere. Therefore, we should make every effort to understand the processes in the atmosphere as best we can and avoid any form of conscious or unconscious manipulation that would have an unknown outcome."The air in the tropical West Pacific is extremely clean. Air masses in this area were transported across the expanse of the huge Pacific with the trade winds and for a long time no longer had contact with forests or other land ecosystems that produce innumerable short-lived hydrocarbons and release them into the air. Under these clean air conditions OH is formed from ozone through chemical transformation to a great degree. If there is hardly any ozone in the lower atmosphere (= troposphere), as is the case in the West Pacific, only little OH can be formed. The result is an OH hole.Ozone, in turn, forms in the lower atmosphere only if there are sufficient nitrogen oxides there. Large amounts of nitrogen oxide compounds are produced in particular by intensive lightning over land. However, the air masses in the tropical West Pacific were not exposed to any continental tropical storms for a very long time during their transport across the giant ocean. And the lightning activity in storms over the ocean is relatively small. At the same time the lifetime of atmospheric ozone is short due to the exceptionally warm and moist conditions in the tropical West Pacific. In this South Sea region the surface temperatures of the ocean are higher than anywhere else on our planet, which makes the air not only quite warm, but also quite moist. The ozone is thus quickly lost, especially directly above the water. And due to the lack of nitrogen oxide compounds little ozone is subsequently formed. Rapid vertical mixing in the convection areas that exist everywhere over the warm ocean and in which the warm air rises takes care of the rest. Finally, there is no more ozone in the entire column of air in the troposphere. And without ozone (see above) the formation of OH is suppressed.The OH molecule is also called the detergent of the atmosphere. Nearly all of the thousands of different chemical substances produced by people, animals, plants, fungi, algae or microorganisms on the ground or in the oceans react quickly with OH and break down in this process. Therefore, virtually none of these substances rises into the stratosphere. In the area of the OH hole, however, a larger portion of this varied chemical mix can enter the stratosphere.And local emissions may unfold a global impact, especially if they make it to the stratosphere. There they spread globally and can influence the composition of the air for many years -- with far-reaching consequences for ozone chemistry, aerosol formation and climate.The tropical West Pacific is one of the most remote regions on our planet. That is why extensive measurements of the air composition have yet to take place in this area. There is also a considerable gap in the otherwise dense network of global ozone measurement stations here. Even in the past measurements from the peripheral sections of the now investigated region showed minimal ozone values in the area of the upper troposphere, but not the consistently low values that have now been found across the entire depth of the troposphere. The newly discovered phenomenon reveals itself in its full scope only through the measurements that were conducted to such an extensive degree for the first time and was thus not able to be grasped at all previously.

Ozone Holes

March 11, 2014

https://www.sciencedaily.com/releases/2014/03/140311100719.htm

New laboratories to foster world-leading research into air quality, climate change

The UK's first dedicated laboratory building for atmospheric chemistry research will be officially opened at the University of York next week.

The Wolfson Atmospheric Chemistry Laboratories will allow researchers to tackle current and emerging atmospheric chemistry issues in an integrated way, enabling world-leading contributions to the science of air quality, ozone depletion and climate change.Supported by a £1.25 million grant from the Wolfson Foundation and a major donation from a benefactor, the new laboratories bring together the world-leading research activities of the University of York and the National Centre for Atmospheric Science.The new research building will be formally opened on Monday, 17 March by Professor A R Ravishankara from the Departments of Chemistry and Atmospheric Science at Colorado State University.Professor Ravishankara will also deliver a public lecture, 'Ozone Layer Depletion and the Montreal Protocol: Can this protocol be pushed further?' at the Ron Cooke Hub to mark the opening. In his lecture, he will describe the evolution of the science of the ozone layer over the past four decades and relate this to the international and national policy changes in limiting, curbing, and eliminating the emissions of ozone depleting substances.The new laboratories will enable York's atmospheric chemistry research teams to be brought together for the first time in one building, and will house faculty staff, post-doctoral researchers, external research staff including from the National Centre for Atmospheric Science and Defra, as well as postgraduates and undergraduates undertaking research projects.Professor Alastair Lewis, from the University's Department of Chemistry and the National Centre for Atmospheric Science, led the development of the project.Professor Lewis said: "As well as bringing together the atmospheric research teams from the Department of Chemistry, the Wolfson Atmospheric Chemistry Laboratories will provide an experimental and modelling infrastructure for interdisciplinary research across the University. The shared workspace has been specifically designed to enhance science-to-policy translation and further increase our active engagement with UK businesses."Paul Ramsbottom, Chief Executive of the Wolfson Foundation, said: "The Wolfson Foundation promotes and supports excellence and we are delighted again to be able to support the University of York. The University's research in atmospheric chemistry is exceptionally strong. It is an area of great significance and yet, despite this, there is a relatively paucity of outstanding groups working in this field in the UK."The laboratories include facilities for trace gas measurements and chemical metrology; studies of aerosol and gas phase processes; atmosphere-biosphere exchange, and computer modelling of chemical mechanisms and atmospheric transport.Atmospheric chemists at York were recently awarded nearly £208,000 from the Natural Environment Research Council (NERC) to invest in new computing infrastructure to develop a 'virtual air' archive. This will allow them to perform retrospective analysis of stored samples of air.The NERC funding forms of part of the Government's Big Data investment which aims to allow the UK research community to take advantage of existing environmental data for science and impact.In total, the Wolfson Atmospheric Chemistry Laboratories have received nearly £1m in capital investments from research councils in the last year, including £570k for a sophisticated high accuracy mass spectrometer, the world's first to be dedicated to environmental research.

Ozone Holes

March 9, 2014

https://www.sciencedaily.com/releases/2014/03/140309150534.htm

Four new human-made ozone depleting gases found in the atmosphere

Scientists at the University of East Anglia have identified four new human-made gases in the atmosphere -- all of which are contributing to the destruction of the ozone layer.

New research published today in the journal Scientists made the discovery by comparing today's air samples with air trapped in polar firn snow -- which provides a century-old natural archive of the atmosphere. They also looked at air collected between 1978 and 2012 in unpolluted Tasmania.Measurements show that all four new gases have been released into the atmosphere recently -- and that two are significantly accumulating. Emission increases of this scale have not been seen for any other CFCs since controls were introduced during the 1990s. But they are nowhere near peak CFC emissions of the 1980s which reached around a million tonnes a year.Lead researcher Dr Johannes Laube from UEA's School of Environmental Sciences said: "Our research has shown four gases that were not around in the atmosphere at all until the 1960s which suggests they are human-made.""CFCs are the main cause of the hole in the ozone layer over Antarctica. Laws to reduce and phase out CFCs came into force in 1989, followed by a total ban in 2010. This has resulted in successfully reducing the production of many of these compounds on a global scale. However, legislation loopholes still allow some usage for exempted purposes."The identification of these four new gases is very worrying as they will contribute to the destruction of the ozone layer. We don't know where the new gases are being emitted from and this should be investigated. Possible sources include feedstock chemicals for insecticide production and solvents for cleaning electronic components."What's more, the three CFCs are being destroyed very slowly in the atmosphere -- so even if emissions were to stop immediately, they will still be around for many decades to come," he added.This research has been funded by the Natural Environment Research Council (NERC), the National Centre for Atmospheric Science (NCAS), the European Union, and the Commonwealth Scientific and Industrial Research Organisation (CSIRO).

Ozone Holes

February 5, 2014

https://www.sciencedaily.com/releases/2014/02/140205113425.htm

Forest emissions, wildfires explain why ancient Earth was so hot

The release of volatile organic compounds from Earth's forests and smoke from wildfires 3 million years ago had a far greater impact on global warming than ancient atmospheric levels of carbon dioxide, a new Yale study finds.

The research provides evidence that dynamic atmospheric chemistry played an important role in past warm climates, underscoring the complexity of climate change and the relevance of natural components, according to the authors. They do not address or dispute the significant role in climate change of human-generated COUsing sophisticated Earth system modeling, a team led by Nadine Unger of the Yale School of Forestry & Environmental Studies (F&ES) calculated that concentrations of tropospheric ozone, aerosol particles, and methane during the mid-Pliocene epoch were twice the levels observed in the pre-industrial era -- largely because so much more of the planet was covered in forest.Those reactive compounds altered Earth's radiation balance, contributing a net global warming as much as two to three times greater than the effect of carbon dioxide, according to the study, published in the journal Geophysical Research Letters.These findings help explain why the Pliocene was two to three degrees C warmer than the pre-industrial era despite atmospheric levels of carbon dioxide that were approximately the same as today, Unger said."The discovery is important for better understanding climate change throughout Earth's history, and has enormous implications for the impacts of deforestation and the role of forests in climate protection strategies," said Unger, an assistant professor of atmospheric chemistry at F&ES."The traditional view," she said, "is that forests affect climate through carbon storage and by altering the color of the planet's surface, thus influencing the albedo effect. But as we are learning, there are other ways that forest ecosystems can impact the climate."The albedo effect refers to the amount of radiation reflected by the surface of the planet. Light-colored snowy surfaces, for instance, reflect more light and heat back into space than darker forests.Climate scientists have suggested that the Pliocene epoch might provide a glimpse of the planet's future if humankind is unable to curb carbon dioxide emissions. During the Pliocene, the two main factors believed to influence the climate -- atmospheric COThe answer might be found in highly reactive compounds that existed long before humans lived on the planet, Unger says. Terrestrial vegetation naturally emits vast quantities of volatile organic compounds, for instance. These are critical precursors for organic aerosols and ozone, a potent greenhouse gas. Wildfires, meanwhile, are a major source of black carbon and primary organic carbon.Forest cover was vastly greater during the Pliocene, a period marked not just by warmer temperatures but also by greater precipitation. At the time, most of the arid and semi-arid regions of Africa, Australia, and the Arabian peninsula were covered with savanna and grassland. Even the Arctic had extensive forests. Notably, Unger says, there were no humans to cut the forests down.Using the NASA Goddard Institute for Space Studies Model-E2 global Earth system model, the researchers were able to simulate the terrestrial ecosystem emissions and atmospheric chemical composition of the Pliocene and the pre-industrial era.According to their findings, the increase in global vegetation was the dominant driver of emissions during the Pliocene -- and the subsequent effects on climate.Previous studies have dismissed such feedbacks, suggesting that these compounds would have had limited impact since they would have been washed from the atmosphere by frequent rainfall in the warmer climate. The new study argues otherwise, saying that the particles lingered about the same length of time -- one to two weeks -- in the Pliocene atmosphere compared to the pre-industrial.Unger says her findings imply a higher climate sensitivity than if the system was simply affected by CO"We might do a lot of work to reduce air pollution from road vehicle and industrial emissions, but in a warmer future world the natural ecosystems are just going to bring the ozone and aerosol particles right back," she said. "Reducing and preventing the accumulation of fossil-fuel COThe modeling calculations were performed on Yale University's omega supercomputer, a 704-node cluster capable of processing more than 52 trillion calculations per second.

Ozone Holes

January 27, 2014

https://www.sciencedaily.com/releases/2014/01/140127193856.htm

Asian ozone pollution in Hawaii is tied to climate variability

Air pollution from Asia has been rising for several decades but Hawaii had seemed to escape the ozone pollution that drifts east with the springtime winds. Now a team of researchers has found that shifts in atmospheric circulation explain the trends in Hawaiian ozone pollution.

The researchers found that since the mid-1990s, these shifts in atmospheric circulation have caused Asian ozone pollution reaching Hawaii to be relatively low in spring but rise significantly in autumn. The study, led by Meiyun Lin, an associate research scholar in the Program in Atmospheric and Oceanic Sciences (NOAA) at Princeton University and a scientist at the National Oceanic and Atmospheric Administration's Geophysical Fluid Dynamics Laboratory, was published in "The findings indicate that decade-long variability in climate must be taken into account when attributing U.S. surface ozone trends to rising Asian emissions," Lin said. She conducted the research with Larry Horowitz and Songmiao Fan of GFDL, Samuel Oltmans of the University of Colorado and the NOAA Earth System Research Laboratory in Boulder; and Arlene Fiore of the Lamont-Doherty Earth Observatory at Columbia University.Although protective at high altitudes, ozone near Earth's surface is a greenhouse gas and a health-damaging air pollutant. The longest record of ozone measurements in the U.S. dates back to 1974 in Hawaii. Over the past few decades, emissions of ozone precursors in Asia has tripled, yet the 40-year Hawaiian record revealed little change in ozone levels during spring, but a surprising rise in autumn.Through their research, Lin and her colleagues solved the puzzle. "We found that changing wind patterns 'hide' the increase in Asian pollution reaching Hawaii in the spring, but amplify the change in the autumn," Lin said.Using chemistry-climate models and observations, Lin and her colleagues uncovered the different mechanisms driving spring versus autumn changes in atmospheric circulation patterns. The findings indicate that the flow of ozone-rich air from Eurasia towards Hawaii during spring weakened in the 2000s as a result of La-Niña-like decadal cooling in the equatorial Pacific Ocean. The stronger transport of Asian pollution to Hawaii during autumn since the mid-1990s corresponds to a positive pattern of atmospheric circulation variability known as the Pacific-North American pattern."This study not only solves the mystery of Hawaiian ozone changes since 1974, but it also has broad implications for interpreting trends in surface ozone levels globally," Lin said. "Characterizing shifts in atmospheric circulation is of paramount importance for understanding the response of surface ozone levels to a changing climate and evolving global emissions of ozone precursors," she said.The work was supported by NOAA's Cooperative Institute for Climate Science at Princeton University. Ozone measurements were obtained at Mauna Loa Observatory, operated by NOAA's Earth System Research Laboratory.

Ozone Holes

January 20, 2014

https://www.sciencedaily.com/releases/2014/01/140120173450.htm

Made in China for us: Air pollution tied to exports

Chinese air pollution blowing across the Pacific Ocean is often caused by the manufacturing of goods for export to the U.S. and Europe, according to findings by UC Irvine and other researchers published today in the

The study is the first to quantify how much pollution reaching the American West Coast is from the production in China of cellphones, televisions and other consumer items imported here and elsewhere."We've outsourced our manufacturing and much of our pollution, but some of it is blowing back across the Pacific to haunt us," said UC Irvine Earth system scientist Steve Davis, a co-author. "Given the complaints about how Chinese pollution is corrupting other countries' air, this paper shows that there may be plenty of blame to go around."Los Angeles, for instance, experiences at least one extra day a year of smog that exceeds federal ozone limits because of nitrogen oxides and carbon monoxide emitted by Chinese factories making goods for export, the analysis found. On other days, as much as a quarter of the sulfate pollution on the U.S. West Coast is tied to Chinese exports. All the contaminants tracked in the study are key ingredients in unhealthy smog and soot.China is not responsible for the lion's share of pollution in the U.S. Cars, trucks and refineries pump out far more. But powerful global winds known as "westerlies" can push airborne chemicals across the ocean in days, particularly during the spring, causing dangerous spikes in contaminants. Dust, ozone and carbon can accumulate in valleys and basins in California and other Western states.Black carbon is a particular problem: Rain doesn't easily wash it out of the atmosphere, so it persists across long distances. Like other air pollutants, it's been linked to a litany of health problems, from increased asthma to cancer, emphysema, and heart and lung disease.The study authors suggest the findings could be used to more effectively negotiate clean-air treaties. China's huge ramp-up of industrial activity in recent years, combined with poor pollution controls, has unleashed often fierce international debates."When you buy a product at Wal-Mart," noted Davis, an assistant professor, "it has to be manufactured somewhere. The product doesn't contain the pollution, but creating it caused the pollution."He and his fellow researchers conclude: "International cooperation to reduce transboundary transport of air pollution must confront the question of who is responsible for emissions in one country during production of goods to support consumption in another."

Ozone Holes

January 15, 2014

https://www.sciencedaily.com/releases/2014/01/140115132742.htm

Arctic: Mercury deposition and ozone depletion, linked to sea-ice dynamics

This week a new study published in

The opening and closing of sea ice leads (large cracks in the ice that expose warmer seawater to the cold polar atmosphere) create a pumping effect, explained Moore, an assistant research professor in DRI's atmospheric science division, that in turn causes atmospheric depletion events to cease. The depletion events are coupled with the destruction of ozone and ultimately the deposition of atmospheric mercury onto snow and ice, a portion of which can enter Arctic ecosystems during snowmelt."The atmospheric mixing created when thinner, seasonal sea ice opens to form leads is so strong," Moore said, "that it actually pulls down mercury from a higher layer of the atmosphere to near the surface."Scientists have long known that complex chemical reactions involving sunlight deposit mercury out of the air to the surface, but these processes normally stop once the mercury near ground level is completely removed. The newly discovered mixing induced by sea ice leads forces down additional mercury to restart and sustain these reactions.Moore and his colleagues, including researchers from NASA's Jet Propulsion Laboratory in Pasadena, Calif., measured increased concentrations of mercury near ground level after leads opened near Barrow, Alaska, in 2012 during the NASA-led Bromine, Ozone, and Mercury Experiment (BROMEX) field project. They also used images from the Moderate Resolution Imaging Spectroradiometer instrument on NASA's Terra satellite to observe sea ice and a National Oceanic and Atmospheric Administration model of air transport to gain insight into what was upwind of their mercury measurements.Obrist, also a research professor at DRI and co-leader of the Institute's Environmental Mercury Laboratory, said, "the 'aha' moment came when we combined satellite data with the air transport model and surface measurements. We considered a variety of chemical processes and sources to explain the increased levels of mercury we observed, until we finally realized it was this pumping process."The authors estimate the mercury pumping occurs about a quarter-mile (400 meters) above the Arctic surface, the height where visible roiling clouds spewing out of sea ice leads extend.Moore said while the initial findings support needed actions to curb mercury pollution across the globe, future research will be needed to establish the degree to which changes in sea ice dynamics across the Arctic alter ozone chemistry and impact mercury deposition throughout the sensitive region.The funding for this research was supported jointly by NASA, Environment Canada, and the Desert Research Institute.

Ozone Holes

January 13, 2014

https://www.sciencedaily.com/releases/2014/01/140113095154.htm

High levels of molecular chlorine found in arctic atmosphere

Scientists studying the atmosphere above Barrow, Alaska, have discovered unprecedented levels of molecular chlorine in the air, a new study reports.

Molecular chlorine, from sea salt released by melting sea ice, reacts with sunlight to produce chlorine atoms. These chlorine atoms are highly reactive and can oxidize many constituents of the atmosphere including methane and elemental mercury, as well activate bromine chemistry, which is an even stronger oxidant of elemental mercury. Oxidized mercury is more reactive and can be deposited to the Arctic ecosystem.The study is the first time that molecular chlorine has been measured in the Arctic, and the first time that scientists have documented such high levels of molecular chlorine in the atmosphere."No one expected there to be this level of chlorine in Barrow or in polar regions," said Greg Huey, a professor in the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology in Atlanta.The study was published January 12 in the journal The researchers directly measured molecular chlorine levels in the Arctic in the spring of 2009 over a six-week period using chemical ionization mass spectrometry. At first the scientists were skeptical of their data, so they spent several years running other experiments to ensure their findings were accurate.The level of molecular chlorine above Barrow was measured as high as 400 parts per trillion, which is a high concentration considering that chlorine atoms are short -lived in the atmosphere because they are strong oxidants and are highly reactive with other atmospheric chemicals.Molecular chlorine concentrations peaked in the early morning and late afternoon, and fell to near-zero levels at night. Average daytime molecular chlorine levels were correlated with ozone concentrations, suggesting that sunlight and ozone may be required for molecular chlorine formation.Previous Arctic studies have documented high levels of oxidized mercury in Barrow and other polar regions. The major source of elemental mercury in the Arctic regions is coal-burning plants around the world. In the spring in Barrow, ozone and elemental mercury are often depleted from the atmosphere when halogens -- chlorine and bromine -- are released into the air from melting sea ice."Molecular chlorine is so reactive that it's going to have a very strong influence on atmospheric chemistry," Huey said.Chlorine atoms are the dominant oxidant in Barrow, the study found. The area is part of a region with otherwise low levels of oxidants in the atmosphere, due to the lack of water vapor and ozone, which are the major precursors to making oxidants in many urban areas.In Barrow, snow-covered ice pack extends in every directly except inland. The ultimate source of the molecular chlorine is the sodium chloride in sea salt, Huey said, most likely from the snow-covered ice pack. How the sea salt is transformed into molecular chlorine is unknown."We don't really know the mechanism. It's a mystery to us right now," Huey said. "But the sea ice is changing dramatically, so we're in a time where we have absolutely no predictive power over what's going to happen to this chemistry. We're really in the dark about the chlorine."Scientists do know that sea ice is rapidly changing, Huey said. The sea ice that lasts from one winter to the next winter is decreasing. This has created a larger area of melted ice, and more ice that comes and goes with the seasons. This seasonal variation in ice could release more molecular chlorine into the atmosphere."There is definite climate change happening in the Arctic," Huey said. "That's changing the nature of the ice, changing the volume of the ice, changing the surface area and changing the chemistry of the ice."

Ozone Holes

December 11, 2013

https://www.sciencedaily.com/releases/2013/12/131211185602.htm

New results from inside the ozone hole

NASA scientists have revealed the inner workings of the ozone hole that forms annually over Antarctica and found that declining chlorine in the stratosphere has not yet caused a recovery of the ozone hole.

More than 20 years after the Montreal Protocol agreement limited human emissions of ozone-depleting substances, satellites have monitored the area of the annual ozone hole and watched it essentially stabilize, ceasing to grow substantially larger. However, two new studies show that signs of recovery are not yet present, and that temperature and winds are still driving any annual changes in ozone hole size."Ozone holes with smaller areas and a larger total amount of ozone are not necessarily evidence of recovery attributable to the expected chlorine decline," said Susan Strahan of NASA's Goddard Space Flight Center in Greenbelt, Md. "That assumption is like trying to understand what's wrong with your car's engine without lifting the hood."To find out what's been happening under the ozone hole's hood, Strahan and Natalya Kramarova, also of NASA Goddard, used satellite data to peer inside the hole. The research was presented Wednesday at the annual meeting of the American Geophysical Union in San Francisco.Kramarova tackled the 2012 ozone hole, the second-smallest hole since the mid 1980s. To find out what caused the hole's diminutive area, she turned to data from the NASA-NOAA Suomi National Polar-orbiting Partnership satellite, and gained the first look inside the hole with the satellite's Ozone Mapper and Profiler Suite's Limb Profiler. Next, data were converted into a map that shows how the amount of ozone differed with altitude throughout the stratosphere in the center of the hole during the 2012 season, from September through November.The map revealed that the 2012 ozone hole was more complex than previously thought. Increases of ozone at upper altitudes in early October, carried there by winds, occurred above the ozone destruction in the lower stratosphere."Our work shows that the classic metrics based on the total ozone values have limitations -- they don't tell us the whole story," Kramarova said.The classic metrics create the impression that the ozone hole has improved as a result of the Montreal protocol. In reality, meteorology was responsible for the increased ozone and resulting smaller hole, as ozone-depleting substances that year were still elevated. The study has been submitted to the journal of Atmospheric Chemistry and Physics.Separate research led by Strahan tackled the holes of 2006 and 2011 -- two of the largest and deepest holes in the past decade. Despite their similar area, however, Strahan shows that they became that way for very different reasons.Strahan used data from the NASA Aura satellite's Microwave Limb Sounder to track the amount of nitrous oxide, a tracer gas inversely related to the amount of ozone depleting chlorine. The researchers were surprised to find that the holes of 2006 and 2011 contained different amounts of ozone-depleting chlorine. Given that fact, how could the two holes be equally severe?The researchers next used a model to simulate the chemistry and winds of the atmosphere. Then they re-ran the simulation with the ozone-destroying reactions turned off to understand the role that the winds played in bringing ozone to the Antarctic. Results showed that in 2011, there was less ozone destruction than in 2006 because the winds transported less ozone to the Antarctic -- so there was less ozone to lose. This was a meteorological, not chemical effect. In contrast, wind blew more ozone to the Antarctic in 2006 and thus there was more ozone destruction. The research has been submitted to the journal Geophysical Research Letters.This work shows that the severity of the ozone hole as measured by the classic total column measurements does not reveal the significant year-to-year variations in the two factors that control ozone: the winds that bring ozone to the Antarctic and the chemical loss due to chlorine.Until chlorine levels in the lower stratosphere decline below the early 1990s level -- expected sometime after 2015 but likely by 2030 -- temperature and winds will continue to dictate the variable area of the hole in any given year. Not until after the mid 2030s will the decline stratospheric chlorine be the primary factor in the decline of ozone hole area."We are still in the period where small changes in chlorine do not affect the area of the ozone hole, which is why it's too soon to say the ozone hole is recovering," Strahan said. "We're going into a period of large variability and there will be bumps in the road before we can identify a clear recovery."

Ozone Holes

December 3, 2013

https://www.sciencedaily.com/releases/2013/12/131203144335.htm

Accelerated corrosion testing of silver provides clues about performance in atmospheric conditions

Small test strips made of silver or other metals, called "coupons," are frequently used to assess and predict the speeds at which metals used in outdoor environments -- pipelines, aircraft, bridges, as well as countless other types of infrastructure and machinery -- will succumb to corrosion.

"Silver is commonly used as a coupon, so it's important to understand what controls its corrosion rate," explains Gerald Frankel, director of the Fontana Corrosion Center, Department of Materials Science and Engineering, The Ohio State University.In a paper recently published in the journal By exploring the effects of all of these corrosive parameters on silver coupons in a "home-built" environment chamber, the researchers discovered that ozone, UV, and relative humidity all play significant roles in silver's corrosion rate.Gaining a deeper understanding of the roles that the individual atmospheric parameters each play in influencing the corrosion rate of metals, such as silver, will enable the development of new models to better predict atmospheric corrosion rates and, ultimately, performance."Our work also involved finding appropriate accelerated lab tests to generate corrosion quickly, and then understanding how the performance of these tests might relate to the performance in real-world atmospheric conditions," Frankel notes.Next, the researchers plan to study other metals that corrode uniformly, such as copper; and metals that corrode in a localized manner, such as aluminum alloys, painted metals, and galvanically coupled dissimilar metals.

Ozone Holes

November 27, 2013

https://www.sciencedaily.com/releases/2013/11/131127110305.htm

Destroying greenhouse gases in environmentally-friendly way

Researchers at the Universitat Jaume I (UJI) have developed a new catalyst for the "activation" of carbon-fluorine bonds. This process has many industrial applications, among which stands out the possibility to be used to reduce existing stocks of CFCs (chloro-fluoro-carbonated compounds), known as "greenhouse gases." CFCs experienced a huge boom in the 80s, but later they were found to destroy the ozone layer because of their photochemical decomposition when they reached the upper layers of the atmosphere.

The Organometallic Chemistry and Homogeneous Catalysis Group coordinated by Eduardo Peris at the UJI has developed "the most active catalyst that exists so far for the activation (in chemical jargon, "break") of carbon-fluorine bonds, which are the strongest bonds in organic molecules, and also the most difficult to break; hence the great difficulty of decomposing organic fluorinated compounds." The relevance of the results obtained has led the work, co-directed by Dr. José A. Mata and with the participation of the doctoral student Sara Sabater, to be published in the prestigious journal Due to their high stability, CFCs experienced a great development during the 80s, mainly for their application in products such as aerosols, fridge gas, etc., until their high detrimental effect was evident: when they reach the atmosphere, by the action of the sun, they decompose creating free radicals that destroy the ozone layer. This discovery caused that a lot of volatile CFC compounds remain in stock, unable to be eliminated due to the high energy costs that it entails. "Thus, we have to try to transform them into less harmful products. Replacing fluorine by hydrogen is a desirable but extremely complicated process due to the inertia of the carbon-fluorine bond," explains the Professor of Inorganic Chemistry. The developed catalyst is very active and effective to perform a controlled destruction of such compounds.The design of the catalyst arises from a conceptually very simple idea: the combination of two different metals that act synergistically. Thus, one of the metal breaks the carbon-fluorine bound (palladium), and the other introduces hydrogen (ruthenium). The idea has generated a great excitement in the specialized forums. The exploitation of heterometallic catalysts (with two different metals) has already placed the UJI's research group at the international forefront of research in catalysis, since the use of heterometallic catalysts enables to sequentially concatenate catalytic processes, and this facilitates obtaining very sophisticated molecules minimizing costs and simplifying the experimental procedures.The group is now working on a new phase of research to facilitate the reverse reaction. "If a catalyst causes a reaction in one direction, it also has to run in the opposite direction. It is what is called 'principle of microscopic reversibility'. In other words, we are now changing carbon-fluorine by carbon-hydrogen and, in theory, the opposite step could also be done. That would facilitate introducing fluorine into other compounds and open up huge possibilities. It would be a big step because it is an extremely difficult reaction. The preparation of fluorinated molecules could have a great impact in different fields, such as in the pharmaceutical industry for drug development. This would be one of the many paths that may be opened if we reach this reverse reaction."

Ozone Holes

November 22, 2013

https://www.sciencedaily.com/releases/2013/11/131122165651.htm

Acid rain, ozone depletion contributed to ancient extinction

Around 250 million years ago, at the end of the Permian period, there was a mass extinction so severe that it remains the most traumatic known species die-off in Earth's history. Some researchers have suggested that this extinction was triggered by contemporaneous volcanic eruptions in Siberia. New results from a team including Director of Carnegie's Department of Terrestrial Magnetism Linda Elkins-Tanton show that the atmospheric effects of these eruptions could have been devastating. Their work is published in

The mass extinction included the sudden loss of more than 90 percent of marine species and more than 70 percent of terrestrial species and set the stage for the rise of the dinosaurs. The fossil record suggests that ecological diversity did not fully recover until several million years after the main pulse of the extinction.One leading candidate for the cause of this event is gas released from a large swath of volcanic rock in Russia called the Siberian Traps. Using advanced 3-D modeling techniques, the team, led by Benjamin Black of the Massachusetts Institute of Technology, was able to predict the impacts of gas released from the Siberian Traps on the end-Permian atmosphere.Their results indicate that volcanic releases of both carbon dioxide (CO2) and sulfur dioxide (SO2) could have created highly acidic rain, potentially leaching the soil of nutrients and damaging plants and other vulnerable terrestrial organisms. Releases of halogen-bearing compounds such as methyl chloride could also have resulted in global ozone collapse.The volcanic activity was likely episodic, producing pulses of acid rain and ozone depletion. The team concluded that the resulting drastic fluctuations in pH and ultraviolet radiation, combined with an overall temperature increase from greenhouse gas emissions, could have contributed to the end-Permian mass extinction on land.The team also included Jean-François Lamarque, Christine Shields, and Jeffrey Kiehl of the National Center for Atmospheric Research.

Ozone Holes

November 11, 2013

https://www.sciencedaily.com/releases/2013/11/131111185520.htm

Global precipitation linked to global warming

The rain in Spain may lie mainly on the plain, but the location and intensity of that rain is changing not only in Spain but around the globe.

A new study by Lawrence Livermore National Laboratory scientists shows that observed changes in global (ocean and land) precipitation are directly affected by human activities and cannot be explained by natural variability alone. The research appears in the Nov. 11 online edition of the Emissions of heat-trapping and ozone-depleting gases affect the distribution of precipitation through two mechanisms. Increasing temperatures are expected to make wet regions wetter and dry regions drier (thermodynamic changes); and changes in atmospheric circulation patterns will push storm tracks and subtropical dry zones toward the poles."Both these changes are occurring simultaneously in global precipitation and this behavior cannot be explained by natural variability alone," said LLNL's lead author Kate Marvel. "External influences such as the increase in greenhouse gases are responsible for the changes."The team compared climate model predications with the Global Precipitation Climatology Project's global observations, which span from 1979-2012, and found that natural variability (such as El Niños and La Niñas) does not account for the changes in global precipitation patterns. While natural fluctuations in climate can lead to either intensification or poleward shifts in precipitation, it is very rare for the two effects to occur together naturally."In combination, manmade increases in greenhouse gases and stratospheric ozone depletion are expected to lead to both an intensification and redistribution of global precipitation," said Céline Bonfils, the other LLNL author. "The fact that we see both of these effects simultaneously in the observations is strong evidence that humans are affecting global precipitation."Marvel and Bonfils identified a fingerprint pattern that characterizes the simultaneous response of precipitation location and intensity to external forcing."Most previous work has focused on either thermodynamic or dynamic changes in isolation. By looking at both, we were able to identify a pattern of precipitation change that fits with what is expected from human-caused climate change," Marvel said.By focusing on the underlying mechanisms that drive changes in global precipitation and by restricting the analysis to the large scales where there is confidence in the models' ability to reproduce the current climate, "we have shown that the changes observed in the satellite era are externally forced and likely to be from man," Bonfils said.

Ozone Holes

October 4, 2013

https://www.sciencedaily.com/releases/2013/10/131004201408.htm

Grains fumigated ecologically

A substance present in nature turned out to be just as effective as other chemical compounds to eradicate harmful organisms in stored grains, without negative effects. Agro a Mexican enterprise that operates silos and warehouses, located in Sinaloa (Northwest Mexico), created a new technology of effective fumigation that solely uses ozone.

Famous weevils, moths and borer beetles live in a very comfortable environment when in the middle of a silo or warehouse fill with grains. There, they perforate the external layer of the stored products, feed freely, have good temperature and enough oxygen to grow and breed.This insects, alongside some fungi, bacteria and viruses, cause annual loses of between four and ten percent of all the stored grains worldwide, mainly corn, wheat, sorghum, rice and beans.Until five years ago, the main fumigation technique and pest control inside warehouses and silos was the use of chemical substances such as aluminum phosphide and methyl bromide, which were effective but left toxic residue for human consumption. However, this can be substituted by an ozone system that ventilates the grains for 48 hours.The ozone removes the comfort zone of the insects making them unable to breathe and modifying the internal atmosphere of the room, using this technique pest free grains are obtained during the whole purchase, sale and storage cycle. The effectiveness of this technology meets the Official Mexican Standard (NOM).This innovation already has industrial property protection and soon will be able to export their ozone fumigation system to Canada. In Mexico, companies with large grain and flour warehouses already use this technology.Thanks to this technological innovations and the business plan created with the help of the Mexico-United Estates Foundation for Science (FUMEC), the Mexican enterprise that had 10 employees in 2008 today counts with 73 permanent employees and 20 temps for gathering season and grain storage.

Ozone Holes

September 9, 2013

https://www.sciencedaily.com/releases/2013/09/130909162338.htm

Aerosols: Chemists develop new approaches to understanding disturbing trends near Earth's surface

Chemists who are members of the American Chemical Society (ACS), collaborating with scientists from other fields through the University of California, San Diego (UCSD) Center for Aerosol Impacts on Climate and the Environment (CAICE), have discovered disturbing climate trends close to Earth's surface.

"The extreme weather we have had in recent years is but one example of the highly complex, global science-based challenges we are now living with," said ACS President Marinda Li Wu, Ph.D. "The climate research conducted by CAICE is providing startling insights that I believe will prove to be as important in protecting human health as the ozone research of 30 years ago."The current research is being led by Kimberly Prather, Ph.D., director of CAICE and UCSD Distinguished Chair in Atmospheric Chemistry, and Vicki Grassian, Ph.D., co-director of CAICE and F. Wendell Miller Professor, Department of Chemistry, The University of Iowa. Grassian is also an ACS Fellow.Thirty years ago, scientists discovered that chlorofluorocarbons degraded ozone high above Earth's surface. Furthermore, particulates, specifically polar stratospheric clouds, played a role in these processes. Subsequently, the Montreal Protocol, an international treaty signed in 1987, was enacted, fostering policies that have protected the ozone layer, and thus, people, from intense ultraviolet radiation ever since.Now, the team led by Prather and Grassian is studying how the more complex troposphere is impacted by aerosols, particulates suspended in the air that can circle the globe in a matter of weeks or even just days. These particulates are emitted from a wide range of sources, including coal-fired power plants, vehicles, wildfires, volcanoes, desert dust and even sea spray. Depending on their chemical make-up, aerosols have been shown to have a vast array of environmental effects, impacting cloud formation, precipitation levels and human health. Yet, aerosols are the most poorly understood component of our atmosphere.

Ozone Holes

September 4, 2013

https://www.sciencedaily.com/releases/2013/09/130904203703.htm

Pacific flights create most amount of ozone

The amount of ozone created from aircraft pollution is highest from flights leaving and entering Australia and New Zealand, a new study has shown.

The findings, which have been published today, Thursday 5 September, in IOP Publishing's journal The researchers, from Massachusetts Institute of Technology, used a global chemistry-transport model to investigate which parts of the world are specifically sensitive to the creation of ozone and therefore which individual flights create the highest amounts.The results showed that an area over the Pacific, around 1000 km to the east of the Solomon Islands, is the most sensitive to aircraft emissions. In this region, the researchers estimated that 1 kg of aircraft emissions -- specifically oxides of nitrogen (NOThe sensitivity in this area was around five times higher than the sensitivity in Europe and 3.7 times higher than the sensitivity in North America.Lead author of the paper, Steven Barrett, said: "Our findings show that the cleanest parts of the atmosphere exhibit the most dramatic response to new emissions. New emissions in this part of the Pacific will result in a relatively larger response from the atmosphere."In an analysis of around 83,000 individual flights, the researchers found that the 10 highest ozone-producing flights either originated, or were destined for, either New Zealand or Australia. A flight from Sydney to Bombay was shown to produce the highest amount of ozone -- 25,300 kg -- as the majority of the flight passed through the area in the Pacific where the sensitivity was the highest.Furthermore, the aircraft leaving and entering Australia and New Zealand are usually very large and the flight times are often very long, meaning more fuel would be burnt and more NOOzone is a relatively short-lived greenhouse gas, and its production and destruction relies heavily on the local chemical state of the atmosphere, so its effects are felt in specific regions at specific times rather than on a global scale.The researchers found that flights in October cause 40 per cent more NO"There have been many studies of the total impact of civil aviation emissions on the atmosphere, but there is very little knowledge of how individual flights change the environment."The places that the sensitivities are highest now are the fastest growing regions in terms of civil aviation growth, so there could potentially be ways to achieve significant reductions in the climate impact of aviation by focusing on re-routing aircraft around the particular regions of the world where ozone formation is highly sensitive to NO"Of course, longer flights are going to burn more fuel and emit more CO

Ozone Holes

September 4, 2013

https://www.sciencedaily.com/releases/2013/09/130904105145.htm

Air pollution worsened by climate change set to be more potent killer in the 21st century

This century, climate change is expected to induce changes in air pollution, exposure to which could increase annual premature deaths by more than 100,000 adults worldwide. Based on the findings from a modelling study published in Springer's journal Climatic Change, lead author Dr. Yuanyuan Fang, formerly at Princeton University and now at the Carnegie Institute for Science at Stanford, urges, in the face of future climate change, stronger emission controls to avoid worsening air pollution and the associated exacerbation of health problems, especially in more populated regions of the world.

Fang and her colleagues ran various present and future simulations using the Geophysical Fluid Dynamics Laboratory Atmospheric Model version 3 (AM3), one of the first fully coupled global chemistry-climate models to integrate atmospheric dynamics, chemistry and physics. An earlier version of this model was ranked among the best in the Intergovernmental Panel on Climate Change Fourth Assessment Report (IPCC AR4). The research team examined the impact of climate change on surface air quality, and how this influences global health statistics. Under a moderate climate change scenario, the simulated global surface temperature and precipitation increased by 2.7⁰C and 6 percent respectively, consistent with findings from the recent IPCC AR4 report.Climate change is believed to harm human health in a variety of ways, including through adverse changes in food production, heat stress, sea level rise, increased storm intensity, flooding and droughts, and increased incidence of vector-borne diseases. In addition, climate change indirectly impacts health by influencing concentrations of air pollutants, such as surface ozone and fine particulate matter (smaller than 2.5 micrometers in diameter), including sulphate, nitrate, fine dust particles and black carbon. These pollutants are linked with increased risks of lung cancer and respiratory, cardiopulmonary, cardiovascular and all-cause deaths.This study shows that climate change will exacerbate air pollution and associated health risks globally and especially over heavily populated and polluted regions of East Asia, South Asia and North America. The increased health risks are mainly driven by an increase in fine particulate matter under climate change. Weaker cyclones and more stagnation over the northeastern United States under future climate conditions are found likely to increase levels of harmful surface ozone over this region.Assuming emissions of air pollutants remain constant, Fang and her colleagues predict that 21st century climate changes will increase air pollution-related premature mortality from all causes worldwide by approximately 100,000 deaths annually. Deaths associated with respiratory diseases because of ozone inhalation could increase by 6,300 deaths annually. The corresponding years of life lost annually (an estimate of the number of years of life lost for each premature death relative to life expectancy) was calculated to be an extra 900,000 years, based on regional statistics provided by the World Health Organisation.Co-author Prof. Denise Mauzerall, Dr. Fang's post-doctoral advisor at Princeton, said, "This climate penalty indicates that stronger emission controls will be needed in the future simply to meet current air quality standards and to avoid higher health risks associated with the worsening of air quality as a result of climate change.""In the future, to improve air quality and protect human health, environmental policies that reduce emissions of greenhouse gases and warming aerosols, in addition to traditional air pollutants, will be beneficial," Fang advised.

Ozone Holes

August 29, 2013

https://www.sciencedaily.com/releases/2013/08/130829093405.htm

Ozone depletion linked to extreme precipitation in austral summer

The new study by Prof. Sarah Kang from Ulsan National Institute of Science and Technology (UNIST), showed that the ozone depletion over the South Pole has affected the extreme daily precipitation in the austral summer, for December, January, and February (DJF).

This work was published in the journal The ozone hole over the Antarctic has affected atmospheric circulation in the Southern Hemisphere (SH) summer and Kang's previous article in Science, analyzed the impact of ozone depletion to increased rainfall in the subtropics.The new article is explaining about the impact of stratospheric ozone depletion on the extreme daily precipitation in the austral summer with two global climate models: the Canadian middle Atmosphere Model (CMAM) and the National Center for Atmospheric Research Community Atmospheric Mode (CAM3).This research study has also been highlighted in the journal The research team led by Prof. Kang focused on a carefully conceived set of multimodel integrations forced only with observed stratospheric ozone changes. This single-forcing approach allows the research team to show extremes, in response to stratospheric ozone depletion and that these changes are likely of a dynamic rather than thermodynamic nature.The ozone layer is a layer in Earth's atmosphere which absorbs most of the UV radiation and contains relatively high concentrations of ozone (OIn this research they discovered that the ozone depletion in the Antarctic area is associated with extreme rain in the austral summer and it would be used to forecast heavy rain and the natural disasters in the future.Dangerous floods have occurred in every Australian state over the last 150 years. Some caused great loss of life, others devastated infrastructure. Between 1852 and 2011 at least 951 people were killed by floods, another 1326 were injured, and the cost of damage reached an estimated $4.76 million dollars.Even though we can predict these natural disasters in advance, we can't stop the flood but we can be prepared for it and reduce the damage."Due to limited data availability in the SH, it is hard to robustly determine observed changes in extreme precipitation," said Prof. Kang. "However, since the recent Southern Hemisphere climate change is driven by the ozone hole, we can deduce the recent trend from our climate model integrations.""We would expand our research to see the correlation of the ozone depletion of the North Pole and the climate changes in the Northern Hemisphere," said Prof. Kang, showing her future research plan.This research was supported by the 2013 Creativity & Innovation Research Fund 1.130033 of UNIST (Ulsan National Institute of Science and Technology).Fellow authors include: L.M. Polvani and G.J.P. Correa from Columbia University, J.C. Fyfe and M. Sigmond from Canadian Centre for Climate Modelling and Analysis, Environment Canada and S.-W. Son from Seoul National University, Korea.*Extreme daily precipitation- The strong precipitation that would happen with 1% probability.

Ozone Holes

August 19, 2013

https://www.sciencedaily.com/releases/2013/08/130819185352.htm

Scientists relate urban population to air pollution

Live in a large city like New York, London, Beijing or Mumbai, and you are likely exposed to more air pollution than people in smaller cities in surrounding areas. But exactly how a city's pollution relates to the size of its population has never been measured, until now.

Using satellite observations, NASA scientists directly measured air pollution's dependence on population in four of the planet's major air pollution regions: the United States, Europe, China and India.The study shows that the pollution-population relationship varies by region. For example, a city of 1 million people in Europe experiences six times higher nitrogen dioxide pollution than an equally populated city of 1 million people in India, according to the research led by Lok Lamsal, of NASA's Goddard Space Flight Center in Greenbelt, Md. The variation is a reflection of regional differences such as industrial development, per capita emissions and geography. The study was published June 13 in Previously, researchers have measured the relationship between population and several urban characteristics, such as infrastructure, employment and innovation. "We show that the relationship is also applicable to pollution," Lamsal said. "Measurement of that relationship is potentially useful for developing future inventories and formulating air pollution control policies."The researchers focused on nitrogen dioxide, or NO2, a common pollutant from the burning of fossil fuels. The gas is a precursor to the formation of near-ground ozone, which can cause respiratory problems and is a problem in many major metropolitan areas. NO2 is also unhealthy to breathe in high concentrations. One feature of the gas, however, is that it's a good proxy for urban air quality.Lok and colleagues studied data collected by the Ozone Monitoring Instrument on NASA's Aura satellite, which measures NO2 throughout the atmosphere in the afternoon around the world. Next they used an air quality computer model to derive from the satellite data the annual mean concentration of the gas near the ground in some of the Northern Hemisphere's major polluting regions, excluding hotspots such as power plants that could skew the urban relationship. By overlaying pollution concentration with population density data, the researchers could examine the relationship.Results across the different regions showed divergent NO2 surface concentrations in urban areas of 1 million people: 0.98 parts per billion (U.S.), 1.33 ppb (Europe), 0.68 ppb (China) and 0.23 ppb (India). The same regions saw various degrees of pollution increases in cities with population of 10 million people: 2.55 ppb (U.S.), 3.86 ppb (Europe), 3.13 ppb (China) and 0.53 ppb (India).The contribution to air pollution from surface-level NO2 in each region more than doubled when cities increased in population from 1 million to 10 million people, although in China the increase was much larger, by about a factor of five.Even though larger cities are typically more energy efficient with lower per-capita emissions, more people still translates to more pollution. But the study reveals some noteworthy regional differences."Energy usage patterns and per capita emissions differ greatly between India and Europe," Lamsal said. "Despite large populations, Indian cities seem cleaner in terms of NO2 pollution than the study's other regions."The researchers say that further investigation is needed in order to clarify the causes behind the regional differences.

Ozone Holes

August 8, 2013

https://www.sciencedaily.com/releases/2013/08/130808124501.htm

Ozone hole might slightly warm planet, computer model suggests

A lot of people mix up the ozone hole and global warming, believing the hole is a major cause of the world's increasing average temperature. Scientists, on the other hand, have long attributed a small cooling effect to the ozone shortage in the hole.

Now a new computer-modeling study suggests that the ozone hole might actually have a slight warming influence, but because of its effect on winds, not temperatures. The new research suggests that shifting wind patterns caused by the ozone hole push clouds farther toward the South Pole, reducing the amount of radiation the clouds reflect and possibly causing a bit of warming rather than cooling."We were surprised this effect happened just by shifting the jet stream and the clouds," said lead author Kevin Grise, a climate scientist at Lamont-Doherty Earth Observatory of Columbia University in New York City.Grise notes this small warming effect may be important for climatologists trying to predict the future of Southern Hemisphere climate.The work is detailed in Each ozone molecule consists of three oxygen atoms bound together. These ozone molecules gather in the lower portion of the stratosphere about 20 to 30 kilometers (12 to 19 miles) above the ground -- about twice as high as commercial airliners fly.Thankfully for the living things below, this layer of ozone shields Earth from some of the hazardous ultraviolet radiation barraging the atmosphere. Unchecked, these ultraviolet rays can cause sunburns, eye damage and even skin cancer.In the 1980s, scientists discovered thinning of the ozone layer above Antarctica during the Southern Hemisphere's spring months. The cause of this "hole" turned out to be chlorofluorocarbons, such as Freon, from cooling systems, aerosols cans and degreasing solvents, which break apart ozone molecules. Even though the1987 Montreal Protocol banned these chlorofluorocarbons worldwide, the ozone hole persists decades later.Many people falsely equate the ozone hole to global warming. In a 2010 Yale University poll, 61 percent of those surveyed believed the ozone hole significantly contributed to global warming. Additionally, 43 percent agreed with the statement "if we stopped punching holes in the ozone layer with rockets, it would reduce global warming."An actual consequence of the ozone hole is its odd effect on the Southern Hemisphere polar jet stream, the fast flowing air currents encircling the South Pole. Despite the ozone hole only appearing during the spring months, throughout each subsequent summer the high-speed jet stream swings south toward the pole."For some reason when you put an ozone hole in the Southern Hemisphere during springtime, you get this robust poleward shift in the jet stream during the following summer season," said Grise. "People have been looking at this for 10 years and there's still no real answer of why this happens."The team of scientists led by Grise wondered if the ozone hole's impacts on the jet stream would have any indirect effects on the cloud cover. Using computer models, they worked out how the clouds would react to changing winds."Because the jet stream shifts, the storm systems move along with it toward the pole," said Grise. "If the storm systems move, the cloud system is going to move with it."High- and mid-level clouds, the team discovered, traveled with the shifting jet stream toward the South Pole and the Antarctic continent. Low-level cloud coverage dropped in their models throughout the Southern Ocean. While modeling clouds is a difficult task due to the variety of factors that guide their formation and movement, Grise noted that observational evidence from the International Satellite Cloud Climatology Project, a decades-long NASA effort to map global cloud distributions, supports their theory of migrating cloud coverage.When the cloud cover moves poleward, the amount of energy the clouds can reflect drops, which increases the amount of radiation reaching the ground. "If you shift the reflector poleward," Grise explained, "you've moved it somewhere there is less radiation coming in."In 2007, the Intergovernmental Panel on Climate Change reported a direct cooling effect from the thinning ozone layer -- specifically, a reduction of about 0.05 watts per square meter's worth of energy reaching the ground. However, Grise and his colleagues estimated the indirect effect of the shifting cloud coverage to be an increase of approximately 0.2 watts per square meter. Their result not only suggests that warming rather than cooling would be taking place, but also that there's a larger influence overall. Since the jet stream only shifts during the summer months, the warming only takes place in those months."Theoretically this net radiation input into the system should give some sort of temperature increase, but it's unknown if that signal could be detected or what the magnitude of it would be," said Grise. For comparison, worldwide, an average of about 175 watts per square meter reaches the ground from sunlight, according to the George Washington University Solar Institute.Dennis Hartmann, an atmospheric scientist at the University of Washington in Seattle unrelated with the project, points out that since predicting cloud behavior is so challenging, the model used in Grise's study could be underestimating clouds north of the jet stream being pulled toward the equator and in turn reflecting more light, potentially reducing or even negating the warming effect. Hartmann added that he also has some concerns about the modeling of the low-level cloud response.Still, "this is certainly a very interesting topic and potentially important from a practical perspective of predicting Southern Hemisphere climate and even global warming rates," he commented.Looking toward the future, the jet stream should do less and less shifting to the south during the summer months as the ozone layer above the South Pole recovers. However, increasing levels of greenhouse gases can also change mid-latitude wind patterns and push the jet stream poleward, creating a complicated scenario which Grise said he plans to study in future work."You have sort of this tug-of-war between the jet being pulled equator-ward during the summer because of the ozone recovery and the greenhouse gases pulling the jet further poleward," said Grise. "What the clouds do in that scenario is an open question."Funding for the research was provided by the National Science Foundation and by the U.S. Department of Energy's Office of Science.

Ozone Holes

August 5, 2013

https://www.sciencedaily.com/releases/2013/08/130805143310.htm

Ozone-protection treaty had climate benefits, too, study says

The global treaty that headed off destruction of earth's protective ozone layer has also prevented major disruption of global rainfall patterns, according to a new study in the

The 1987 Montreal Protocol phased out the use of chloroflourocarbons, or CFCs, a class of chemicals that destroy ozone in the stratosphere, allowing more ultraviolet radiation to reach earth's surface. Though the treaty aimed to reverse ozone losses, the new research shows that it also protected the hydroclimate. The study says the treaty prevented ozone loss from disrupting atmospheric circulation, and kept CFCs, which are greenhouse gases, from warming the atmosphere and also disrupting atmospheric circulation. Had these effects taken hold, they would have combined to shift rainfall patterns in ways beyond those that may already be happening due to rising carbon dioxide in the air.At the time the Montreal Protocol was drafted, the warming potential of CFCs was poorly understood, and the impact of ozone depletion on surface climate and the hydrological cycle was not recognized at all. "We dodged a bullet we did not know had been fired," said study coauthor Richard Seager, a climate scientist at Columbia University's Lamont-Doherty Earth Observatory.Today, rising carbon dioxide levels are already disturbing earth's hydrological cycle, making dry areas drier and wet areas wetter. But in computer models simulating a world of continued CFC use, the researchers found that the hydrological changes in the decade ahead, 2020-2029, would have been twice as severe as they are now expected to be. Subtropical deserts, for example in North America and the Mediterranean region, would have grown even drier and wider, the study says, and wet regions in the tropics, and mid-to-high latitudes would have grown even wetter.The ozone layer protects life on earth by absorbing harmful ultraviolet radiation. As the layer thins, the upper atmosphere grows colder, causing winds in the stratosphere and in the troposphere below to shift, displacing jet streams and storm tracks. The researchers' model shows that if ozone destruction had continued unabated, and increasing CFCs further heated the planet, the jet stream in the mid-latitudes would have shifted toward the poles, expanding the subtropical dry zones and shifting the mid-latitude rain belts poleward. The warming due to added CFCs in the air would have also intensified cycles of evaporation and precipitation, causing the wet climates of the deep tropics and mid to high latitudes to get wetter, and the subtropical dry climates to get drier.The study builds on earlier work by coauthor Lorenzo Polvani, a climate scientist with joint appointments at Lamont-Doherty and Columbia's Fu Foundation School of Engineering and Applied Science. Polvani and others have found that two human influences on climate --ozone loss and industrial greenhouse gases -- have together pushed the jet stream in the southern hemisphere south over recent decades. As the ozone hole over Antarctica closes in the coming decades, the jet stream will stop its poleward migration, Polvani found in a 2011 study in the journal Geophysical Research Letters. The projected stopping of the poleward jet migration is a result of the ozone hole closing, canceling the effect of increasing greenhouse gases."We wanted to take a look at the more drastic scenario -- what would have happened if there had been no Montreal Protocol?" said study lead author Yutian Wu, a former Lamont graduate student who is now a postdoctoral researcher at New York University. "The climatic impacts of CFCs and ozone depletion were not known back then."The Montreal Protocol is considered one of the most successful environmental treaties of all time. Once scientists linked CFCs to rapid ozone loss over Antarctica, world leaders responded quickly. Nearly 200 countries have ratified the treaty. The ozone depletion that CFCs would have caused is now known to have been far worse than was realized at the time, in 1987. The cost of developing CFC-substitutes also turned out to be far less than the industry estimated."It's remarkable that the Montreal Protocol has not only been important in protecting the ozone layer and in decreasing global warming but that it also has had an important effect on rainfall patterns and reducing the changes we are in for," said Susan Solomon, an atmospheric scientist at the Massachusetts Institute of Technology who won the Vetlesen Prize earlier this year for her work on ozone depletion. Solomon was not involved in the study.As a greenhouse gas, CFCs can be thousands of times more potent than carbon dioxide. Dutch scientist Guus Velders estimated in a 2007 study that had the chemicals not been phased out, by 2010 they would have generated the warming equivalent of more than 220 billion tons of carbon dioxide. (Humans produced 32 billion tons of COHydroflourocarbons, or HFCs, have largely replaced CFCs as refrigerants, aerosol propellants and other products. While HFCs are ozone-safe, they, too, are powerful greenhouse gases that have become a concern as world leaders grapple with climate change. The Kyoto Protocol was drafted to regulate global greenhouse gas emissions, but its expiration at the end of 2012 has led some countries to seek climate protections from the Montreal Protocol. Micronesia, Canada, Mexico and the United States have asked that HFCs be regulated under Montreal. So far no action has been taken."This research supports the principle that it's generally best not to put things into the environment that weren't there before," said Scott Barrett, an economist at the Earth Institute who was not involved in the study. "It's a lesson, surely, for our current efforts to limit greenhouse gas emissions."

Ozone Holes

July 19, 2013

https://www.sciencedaily.com/releases/2013/07/130719083912.htm

It's not just the heat, it's the ozone: Hidden heat wave dangers exposed

During heat waves -- when ozone production rises -- plants' ozone absorption is curtailed, leaving more pollution in the air.This resulted in the loss of an estimated 460 lives in the UK in the hot summer of 2006.

Vegetation plays a crucial role in reducing air pollution, but new research by the Stockholm Environment Institute (SEI) at the University of York shows that they may not protect us when we need it most: during extreme heat, when ozone formation from traffic fumes, industrial processes and other sources is at its worst.The reason, explained lead author Dr Lisa Emberson, is that during heat waves -- when the ground is especially dry -- plants become stressed and shut their stomata (small pores on their leaves) to conserve water. This natural protective mechanism makes them more resilient to extreme heat and high ozone levels, but it also stops them from absorbing ozone and other pollutants."Vegetation can absorb as much as 20 per cent of the global atmospheric ozone production, so the potential impact on air quality is substantial," says Dr Emberson, a senior lecturer in the Environment Department at the University of York and director of SEI's York Centre. "What we set out to do in this study was to quantify that impact in terms of increased ozone levels and the toll on human life."The research team, which also included scientists at King's College, London, focused on the summer of 2006, when a heat wave and drought occurred across the UK and much of Europe. They combined two models used for human health and ecosystem risk assessment to compare two scenarios, one with perfect ozone uptake by plants, and one with minimal ozone absorption.The difference between perfect and minimal uptake was equivalent to 16 days of ozone levels above the threshold for human safety across the entire UK -- and as many as 20 days in the East Midlands and eastern UK. Using these same scenarios, the team also estimated that 970 premature deaths due to ozone would have occurred under minimal plant ozone uptake conditions over the June to July period; of these 460 could have been avoided if plants had been absorbing ozone at full capacity. All estimated premature deaths are in addition to human health and mortality impacts from the heat itself."The most vulnerable people to ozone pollution are those with existing respiratory and cardiovascular diseases," explains Dr Emberson. "For example, ground-level ozone can lead to lung inflammation, decreased lung function, and an increase in asthma attacks. That is why, during high ozone episodes, especially in urban areas, people are generally advised not to do physical activity."The study findings were published this week in the peer-reviewed journal The timing of the publication coincides with yet another major heat wave in the UK, and Dr Emberson says it is likely that ozone uptake by vegetation is once again curtailed. The extent of the problem, however, will depend on how dry the soil is, since it is the combination of heat and drought that stresses plants the most.Dr Emberson says the study highlights the importance of understanding the frequency with which such heat waves and droughts will occur in the future as well as how ozone uptake by vegetation is affected by droughts, extreme heat, and interaction with other pollutants."The more we know, the better we will be able to judge how successful our emission reduction efforts have been so far, and whether we need additional efforts -- in the UK, across Europe and beyond, since we know that pollutants such as ozone and its precursors can carried around the globe," she says.The research can also inform public-health responses, Dr Emberson says. For example, people may mistakenly believe that as long as they get out of the city, they are not at risk from poor air quality, so it is important to raise their awareness. Greater efforts can also be made to reduce traffic congestion and other sources of ozone-forming pollutants -- every day, but especially during heat waves.

Ozone Holes

July 12, 2013

https://www.sciencedaily.com/releases/2013/07/130712084455.htm

Air pollution responsible for more than 2 million deaths worldwide each year, experts estimate

More than two million deaths occur worldwide each year as a direct result of human-caused outdoor air pollution, a new study has found.

In addition, while it has been suggested that a changing climate can exacerbate the effects of air pollution and increase death rates, the study shows that this has a minimal effect and only accounts for a small proportion of current deaths related to air pollution.The study, which has been published today, 12 July, in IOP Publishing's journal It also estimates that around 2.1 million deaths are caused each year by human-caused increases in fine particulate matter (PMCo-author of the study, Jason West, from the University of North Carolina, said: "Our estimates make outdoor air pollution among the most important environmental risk factors for health. Many of these deaths are estimated to occur in East Asia and South Asia, where population is high and air pollution is severe."According to the study, the number of these deaths that can be attributed to changes in the climate since the industrial era is, however, relatively small. It estimates that a changing climate results in 1500 deaths due to ozone and 2200 deaths related to PMClimate change affects air quality in many ways, possibly leading to local increases or decreases in air pollution. For instance, temperature and humidity can change the reaction rates which determine the formation or lifetime of a pollutant, and rainfall can determine the time that pollutants can accumulate.Higher temperatures can also increase the emissions of organic compounds from trees, which can then react in the atmosphere to form ozone and particulate matter."Very few studies have attempted to estimate the effects of past climate change on air quality and health. We found that the effects of past climate change are likely to be a very small component of the overall effect of air pollution," continued West.In their study, the researchers used an ensemble of climate models to simulate the concentrations of ozone and PMPrevious epidemiological studies were then used to assess how the specific concentrations of air pollution from the climate models related to current global mortality rates.The researchers' results were comparable to previous studies that have analysed air pollution and mortality; however, there was some variation depending on which climate model was used."We have also found that there is significant uncertainty based on the spread among different atmospheric models. This would caution against using a single model in the future, as some studies have done," continued West.

Ozone Holes

July 4, 2013

https://www.sciencedaily.com/releases/2013/07/130704095132.htm

Climate change deniers using dirty tricks from 'Tobacco Wars', expert says

Fossil fuel companies have been funding smear campaigns that raise doubts about climate change, writes John Sauven in the latest issue of

Environmental campaigner Sauven argues: "Some of the characters involved have previously worked to deny the reality of the hole in the ozone layer, acid rain and the link between tobacco and lung cancer. And the tactics they are applying are largely the same as those they used in the tobacco wars. Doubt is still their product."Governments around the world have also attempted to silence scientists who have raised concerns about climate change. Tactics used have included: Writing about government corruption in the Indian mining industry, Sauven says: "It will be in these expanding economies that the battle over the Earth's future will be won or lost. And as in the tobacco wars, the fight over clean energy is likely to be a dirty one."

Ozone Holes

June 13, 2013

https://www.sciencedaily.com/releases/2013/06/130613092346.htm

'Self-cleaning' pollution-control technology could do more harm than good, study suggests

Research by Indiana University environmental scientists shows that air-pollution-removal technology used in "self-cleaning" paints and building surfaces may actually cause more problems than they solve.

The study finds that titanium dioxide coatings, seen as promising for their role in breaking down airborne pollutants on contact, are likely in real-world conditions to convert abundant ammonia to nitrogen oxide, the key precursor of harmful ozone pollution."As air quality standards become more stringent, people are going to be thinking about other technologies that can reduce pollution," said Jonathan D. Raff, assistant professor in the School of Public and Environmental Affairs at IU Bloomington and an author of the study. "Our research suggests that this may not be one of them.""Photooxidation of Ammonia on TiO2 as a Source of NO and NO2 under Atmospheric Conditions" is being published by the The researchers calculate that, in areas where the titanium dioxide technology is used, ammonia degradation could account for up to 13 percent of the nitrogen oxides in the immediate vicinity. This suggests that widespread use of the technology could contribute significantly to ozone formation.The findings are timely because the Environmental Protection Agency is developing stricter regulations for ground-level ozone, a primary component in photochemical smog. The pollution is linked to serious health problems, including breathing difficulties and heart and lung disease.Ozone is produced by reactions involving nitrogen oxides (NOx), which come primarily from motor vehicle emissions, and volatile organic compounds resulting from industrial processes. Equipping cars with catalytic converters has been effective at reducing ozone in urban areas. But different technologies may be needed to meet tighter air-quality standards of the future.The need has sparked interest in titanium dioxide, a common mineral that is used as a whitening agent in paints and surface coatings. The compound acts as a photocatalyst, breaking down nitrogen oxides, ammonia and other pollutants in the presence of sunlight. "Self-cleaning" surfaces coated with titanium dioxide can break down chemical grime that will otherwise adhere to urban buildings. News stories have celebrated "smog-eating" tiles and concrete surfaces coated with the compound.But Raff and his colleagues show that, in normal environmental conditions, titanium dioxide also catalyzes the incomplete breakdown of ammonia into nitrogen oxides. Ammonia is an abundant constituent in motor vehicle emissions, and its conversion to nitrogen oxides could result in increases in harmful ozone concentrations."We show that uptake of atmospheric NH3 (ammonia) onto surfaces containing TiO2 (titanium dioxide) is not a permanent removal process, as previously thought, but rather a photochemical route for generating reactive oxides of nitrogen that play a role in air pollution and are associated with significant health effects," the authors write.Raff, who is also an adjunct professor of chemistry in the IU College of Arts and Sciences, said other studies missed the effect on ammonia because they investigated reactions that occur with high levels of emissions under industrial conditions, not the low levels and actual humidity levels typically present in urban environments.The findings also call into question other suggestions for using titanium dioxide for environmental remediation -- for example, to remove odor-causing organic compounds from emissions produced by confined livestock feeding operations. Titanium dioxide has also been suggested as a geo-engineering substance that could be injected into the upper atmosphere to reflect sunlight away from Earth and combat global warming.Further studies in Raff's lab are aimed at producing better understanding of the molecular processes involved when titanium dioxide catalyzes the breakdown of ammonia. The results could suggest approaches for developing more effective pollution-control equipment as well as improvements in industrial processes involving ammonia.

Ozone Holes

May 30, 2013

https://www.sciencedaily.com/releases/2013/05/130530132443.htm

Global warming caused by CFCs, not carbon dioxide, researcher claims in controversial study

Chlorofluorocarbons (CFCs) are to blame for global warming since the 1970s and not carbon dioxide, according to a researcher from the University of Waterloo in a controversial new study published in the

CFCs are already known to deplete ozone, but in-depth statistical analysis now suggests that CFCs are also the key driver in global climate change, rather than carbon dioxide (CO"Conventional thinking says that the emission of human-made non-CFC gases such as carbon dioxide has mainly contributed to global warming. But we have observed data going back to the Industrial Revolution that convincingly shows that conventional understanding is wrong," said Qing-Bin Lu, a professor of physics and astronomy, biology and chemistry in Waterloo's Faculty of Science. "In fact, the data shows that CFCs conspiring with cosmic rays caused both the polar ozone hole and global warming.""Most conventional theories expect that global temperatures will continue to increase as COThe findings are based on in-depth statistical analyses of observed data from 1850 up to the present time, Professor Lu's cosmic-ray-driven electron-reaction (CRE) theory of ozone depletion and his previous research into Antarctic ozone depletion and global surface temperatures."It was generally accepted for more than two decades that the Earth's ozone layer was depleted by the sun's ultraviolet light-induced destruction of CFCs in the atmosphere," he said. "But in contrast, CRE theory says cosmic rays -- energy particles originating in space -- play the dominant role in breaking down ozone-depleting molecules and then ozone."Lu's theory has been confirmed by ongoing observations of cosmic ray, CFC, ozone and stratospheric temperature data over several 11-year solar cycles. "CRE is the only theory that provides us with an excellent reproduction of 11-year cyclic variations of both polar ozone loss and stratospheric cooling," said Professor Lu. "After removing the natural cosmic-ray effect, my new paper shows a pronounced recovery by ~20% of the Antarctic ozone hole, consistent with the decline of CFCs in the polar stratosphere."By demonstrating the link between CFCs, ozone depletion and temperature changes in the Antarctic, Professor Lu was able to draw almost perfect correlation between rising global surface temperatures and CFCs in the atmosphere."The climate in the Antarctic stratosphere has been completely controlled by CFCs and cosmic rays, with no COData recorded from 1850 to 1970, before any significant CFC emissions, show that COThe analyses support Lu's CRE theory and point to the success of the Montreal Protocol on Substances that Deplete the Ozone Layer."We've known for some time that CFCs have a really damaging effect on our atmosphere and we've taken measures to reduce their emissions," Professor Lu said. "We now know that international efforts such as the Montreal Protocol have also had a profound effect on global warming but they must be placed on firmer scientific ground.""This study underlines the importance of understanding the basic science underlying ozone depletion and global climate change," said Terry McMahon, dean of the faculty of science. "This research is of particular importance not only to the research community, but to policy makers and the public alike as we look to the future of our climate."Professor Lu's paper, "Cosmic-Ray-Driven Reaction and Greenhouse Effect of Halogenated Molecules: Culprits for Atmospheric Ozone Depletion and Global Climate Change," also predicts that the global sea level will continue to rise for some years as the hole in the ozone recovers increasing ice melting in the polar regions."Only when the effect of the global temperature recovery dominates over that of the polar ozone hole recovery, will both temperature and polar ice melting drop concurrently," says Lu.The peer-reviewed paper published this week not only provides new fundamental understanding of the ozone hole and global climate change but has superior predictive capabilities, compared with the conventional sunlight-driven ozone-depleting and CO

Ozone Holes

May 22, 2013

https://www.sciencedaily.com/releases/2013/05/130522131158.htm

Tropical upper atmosphere 'fingerprint' of global warming

In the tropics at heights more than 10 miles above the surface, the prevailing winds alternate between strong easterlies and strong westerlies roughly every other year. This slow heartbeat in the tropical upper atmosphere, referred to as the quasibiennial oscillation (QBO), impacts the winds and chemical composition of the global atmosphere and even the climate at Earth's surface.

The pulse of the QBO has weakened substantially at some altitudes over the last six decades, according to a new study by scientists at the International Pacific Research Center, University of Hawaii at Manoa, and the Japan Agency for Marine-Earth Science and Technology. The decline in the strength of the QBO is consistent with computer model projections of how the upper atmosphere responds to global warming induced by increased greenhouse gas concentrations. The study appears in the May 23, 2013, online issue of "This is the first demonstration of a systematic long-term trend in the observed QBO record," says co-author Kevin Hamilton and Director of the IPRC. "We see a similar trend in computer models of the global atmosphere when they simulate the last century using the historical changes of greenhouse gases. So this change in upper atmospheric behavior can be considered part of the "fingerprint" of the expected global warming signal in the climate system."The global atmospheric circulation is characterized by air slowly rising in the tropics into the upper atmosphere and sinking at higher latitudes. While this circulation is so slow that a blob of air may take decades to travel to the upper atmosphere, it impacts the chemical composition of the global atmosphere because many chemical properties are very different in the lower and upper atmosphere layers. Although computer models used to project climate changes from increasing greenhouse gas concentrations consistently simulate an increasing upward airflow in the tropics with global warming, this flow cannot be directly observed."We demonstrated that the mean upward-air motion suppresses the strength of the QBO winds in the models and thus interpret our observed weakened QBO trend as confirmation that the mean upward velocity in the tropics has indeed been increasing," notes Hamilton.Hamilton provides an example of why the upward airflow is so significant: "The manufacture of ozone-destroying chemicals such as the freon compounds used in the past in spray cans and in refrigerators has been largely banned for over 20 years. These chemicals, however, remain in the atmosphere for many decades. They are slowly flushed out of the lower atmosphere into the upper atmosphere where they are destroyed. Stronger mean upward airflow transports these chemicals more quickly into the upper atmosphere, and the ozone layer will recover more quickly to its natural state before the introduction of man-made freon compounds."

Ozone Holes

April 26, 2013

https://www.sciencedaily.com/releases/2013/04/130426114858.htm

Scientists investigate release of bromine in polar regions

The chemical element bromine, whose compounds contribute significantly to the depletion of ozone in the lower atmosphere, is also released in polar regions to a great extent from snow on land. This is the result reached by an international research team of scientists from the Institute of Environmental Physics of Heidelberg University and colleagues from the USA, who performed measurements and sampling together in Alaska. Until now, science has assumed that sea ice was the sole source of bromine emissions. A novel spectroscopic measurement device, developed in Heidelberg, was used aboard an American research aircraft for this study.

The results of this research have now been published in Ozone plays a key role not only in the stratosphere, but also on the ground. While at ground level it is not particularly relevant for the protection from UV radiation, it is for the self-cleaning of the atmosphere and removal of contaminants. In the 1990s Heidelberg researchers working with Prof. Dr. Ulrich Platt had already discovered that the extensive ozone depletion in the atmosphere close to the ground in the Arctic and Antarctic was due to a reaction of bromine with ozone, producing bromine oxide. This bromine is released in autocatalytic processes. During the polar spring, the resulting bromine oxide clouds can spread over several thousand square kilometres. "It is by far the largest release of bromine on our planet," says Prof. Platt of the Institute of Environmental Physics at Heidelberg University. The precise processes involved are quite complex and are still a topic of current research.Now the investigations in Alaska by the international team of scientists have yielded new information on the release of bromine from ice and snow. The researchers studied a variety of samples taken on site. It appears that the bromine-release processes are correlated to daylight, and thus involve photochemical reactions. Most importantly, however, the team was able to prove that the bromine emissions depended heavily on the pH value of the snow or ice sample. "The more acidic the sample, the more bromine was released. This led to the surprising result that snow on land, which is typically acidic, releases more bromine than alkaline sea ice, even though sea ice clearly contains more bromine," explains Dr. Denis Pöhler, a member of Prof. Platt's team.The scientists from Heidelberg University confirmed these findings particularly through simultaneous observations from the aircraft. The instrument, which was developed as part of a project funded by the German Research Foundation at the Institute of Environmental Physics, measures the sunlight reflected and scattered on the surface of the snow and in the atmosphere. Bromine oxide absorbs some of the sunlight. Based on the amount of absorption, the Heidelberg scientists were able to determine the bromine concentration and its vertical distribution up to several kilometres altitude. They also obtained data on its horizontal distribution. "This kind of comprehensive data allows us to precisely find the sources of bromine release in the Arctic," stresses Dr. Pöhler.The studies were conducted as part of the "Bromine, Ozone and Mercury Experiment" (BROMEX). Collaborators included researchers from Purdue University in West Lafayette/Indiana, the Cold Regions Research and Engineering Laboratory in Fort Wainwright/Alaska, the University of Alaska Fairbanks and the Georgia Institute of Technology in Atlanta. The instrument developed in Heidelberg will be used aboard the new German HALO research aircraft to measure not only bromine oxide, but also other compounds of significance for the atmosphere, such as nitrogen dioxide and sulphur dioxide.

Ozone Holes

April 24, 2013

https://www.sciencedaily.com/releases/2013/04/130424132705.htm

Ancient Earth crust stored in deep mantle

Scientists have long believed that lava erupted from certain oceanic volcanoes contains materials from the early Earth's crust. But decisive evidence for this phenomenon has proven elusive. New research from a team including Carnegie's Erik Hauri demonstrates that oceanic volcanic rocks contain samples of recycled crust dating back to the Archean era 2.5 billion years ago. Their work is published in

Oceanic crust sinks into Earth's mantle at so-called subduction zones, where two plates come together. Much of what happens to the crust during this journey is unknown. Model-dependent studies for how long subducted material can exist in the mantle are uncertain and evidence of very old crust returning to Earth's surface via upwellings of magma has not been found until now.The research team studied volcanic rocks from the island of Mangaia in Polynesia's Cook Islands that contain iron sulfide inclusions within crystals. In-depth analysis of the chemical makeup of these samples yielded interesting results.The research focused on isotopes of the element sulfur. (Isotopes are atoms of the same element with different numbers of neutrons.) The measurements, conducted by graduate student Rita Cabral, looked at three of the four naturally occurring isotopes of sulfur--isotopic masses 32, 33, and 34. The sulfur-33 isotopes showed evidence of a chemical interaction with UV radiation that stopped occurring in Earth's atmosphere about 2.45 billion years ago. It stopped after the Great Oxidation Event, a point in time when Earth's atmospheric oxygen levels skyrocketed as a consequence of oxygen-producing photosynthetic microbes. Prior to the Great Oxidation Event, the atmosphere lacked ozone. But once ozone was introduced, it started to absorb UV and shut down the process.This indicates that the sulfur comes from a deep mantle reservoir containing crustal material subducted before the Great Oxidation Event and preserved for over half the age of Earth."These measurements place the first firm age estimates of recycled material in oceanic hotspots," Hauri said. "They confirm the cycling of sulfur from the atmosphere and oceans into mantle and ultimately back to the surface," Hauri said.

Ozone Holes

April 24, 2013

https://www.sciencedaily.com/releases/2013/04/130424112305.htm

Sunlit snow triggers atmospheric cleaning, ozone depletion in the Arctic

National Science Foundation-funded researchers at Purdue University have discovered that sunlit snow is the major source of atmospheric bromine in the Arctic, the key to unique chemical reactions that purge pollutants and destroy ozone.

The new research also indicates that the surface snowpack above Arctic sea ice plays a previously unappreciated role in the bromine cycle and that loss of sea ice, which been occurring at an increasingly rapid pace in recent years, could have extremely disruptive effects in the balance of atmospheric chemistry in high latitudes.The team's findings suggest the rapidly changing Arctic climate--where surface temperatures are rising three times faster than the global average--could dramatically change its atmospheric chemistry, said Paul Shepson, an NSF-funded researcher who led the research team. The experiments were conducted by Kerri Pratt, a postdoctoral researcher funded by the Division of Polar Programs in NSF's Geosciences Directorate."We are racing to understand exactly what happens in the Arctic and how it affects the planet because it is a delicate balance when it comes to an atmosphere that is hospitable to human life," said Shepson, who also is a founding member of the Purdue Climate Change Research Center. "The composition of the atmosphere determines air temperatures, weather patterns and is responsible for chemical reactions that clean the air of pollutants."A paper detailing the results of the research, some of which was funded by NSF and some by the National Aeronautics and Space Administration, was recently published online at Ozone in the lower atmosphere behaves differently from the stratospheric ozone involved in the planet's protective ozone layer. This lower atmosphere ozone is a greenhouse gas that is toxic to humans and plants, but it also is an essential cleaning agent of the atmosphere.Interactions between sunlight, ozone and water vapor create an "oxidizing agent" that scrubs the atmosphere of most of the pollutants human activity releases into it, Shepson said.Temperatures at the poles are too cold for the existence of much water vapor and in the Arctic this cleaning process appears instead to rely on reactions on frozen surfaces involving molecular bromine, a halogen gas derived from sea salt.This gaseous bromine reacts with and destroys atmospheric ozone. This aspect of the bromine chemistry works so efficiently in the Arctic that ozone is often entirely depleted from the atmosphere above sea ice in the spring, Shepson noted."This is just a part of atmospheric ozone chemistry that we don't understand very well, and this unique Arctic chemistry teaches us about the potential role of bromine in other parts of the planet," he said. "Bromine chemistry mediates the amount of ozone, but it is dependent on snow and sea ice, which means climate change may have important feedbacks with ozone chemistry."While it was known that there is more atmospheric bromine in polar regions, the specific source of the natural gaseous bromine has remained in question for several decades, said Pratt, a Polar Programs-funded postdoctoral fellow and lead author of the paper."We thought that the fastest and best way to understand what is happening in the Arctic was to go there and do the experiments right where the chemistry is happening," Pratt said.She and Purdue graduate student Kyle Custard performed the experiments in -45 to -34 Celsius (-50 to -30 Fahrenheit) wind chills near Barrow, Alaska. The team examined first-year sea ice, salty icicles and snow and found that the source of the bromine gas was the top surface snow above both sea ice and tundra."Sea ice had been thought to be the source of the gaseous bromine," she said. "We had an 'of course!' moment when we realized it was the snow on top of the sea ice. The snow is what is in direct contact with the atmosphere. Sea ice is critical to the process, though. Without it, the snow would fall into the ocean, and this chemistry wouldn't take place. This is among the reasons why the loss of sea ice in the Arctic will directly impact atmospheric chemistry."The team also discovered that sunlight triggered the release of bromine gas from the snow and the presence of ozone increased the production of bromine gas."Salts from the ocean and acids from a layer of smog called Arctic haze meet on the frozen surface of the snow, and this unique chemistry occurs," Pratt said. "It is the interface of the snow and atmosphere that is the key."A series of chemical reactions that quickly multiplies the amount of bromine gas present, called the "bromine explosion," is known to occur in the atmosphere. The team suggests this also occurs in the spaces between the snow crystals and wind then releases the bromine gas up into the air above the snow.The team performed 10 experiments with snow and ice samples contained in a "snow chamber," a box constructed of aluminum with a special coating to prevent surface reactions and a clear acrylic top. Clean air with and without ozone was allowed to flow through the chamber and experiments were performed in darkness and in natural sunlight.The team also measured the levels of bromine monoxide, a compound formed from the reaction of bromine atoms with ozone, through flights of the Purdue Airborne Laboratory for Atmospheric Research.Shepson is the pilot of this specially equipped aircraft, which he and air operations technical specialist Brian Stirm flew from Indiana to Barrow for these experiments. They found the compound was most prevalent over snow-covered first-year sea ice and tundra, consistent with their snow chamber experiments.The experiments were performed from March to April 2012 and were part of NASA's Bromine, Ozone and Mercury Experiment, or BROMEX. The goal of the study is to understand the implications of Arctic sea ice reduction on tropospheric chemistry.Shepson's group next plans to perform laboratory studies to test the proposed reaction mechanisms and to return to Barrow to perform more snow chamber experiments.In addition, Shepson is co-leading a team using ice-tethered buoys to measure carbon dioxide, ozone and bromine monoxide across the Arctic Ocean, and Pratt is working with scientists from the University of Washington to examine the chemistry of snow from across the Arctic Ocean."In the Arctic, climate change is happening at an accelerated pace," Pratt said. "A big question is what will happen to atmospheric composition in the Arctic as the temperatures rise and snow and ice decline even further?"

Ozone Holes

April 2, 2013

https://www.sciencedaily.com/releases/2013/04/130402150145.htm

Ozone masks plants volatiles, plant eating insects confused

Increases in ground-level ozone, especially in rural areas, may interfere not only with predator insects finding host plants, but also with pollinators finding flowers, according to researchers from Penn State and the University of Virginia.

"Ozone pollution has great potential to perniciously alter key interactions between plants and animals," the researchers said in a recent issue ofThe animal tested in this case was the striped cucumber beetle, a predator of cucurbits -- cucumber, squash, pumpkin and melons. These insects dine on the plants from the moment they emerge from the ground and when fruit forms, they eat that as well."Insects detect odor with olfactory receptors located on their antennae," said Jose D. Fuentes, professor of meteorology, Penn State. "These receptors sense plant-emitted volatile organic compounds in very small amounts -- as low as six molecules hitting an antenna."However, ozone, which is a very reactive substance, degrades the volatile organic compounds when they mix to the point where they no longer stimulate the olfactory system.Fuentes, working with John Zenker, Penn State undergraduate in meteorology, and T'ai H. Roulston, research associate professor and curator, Blandy Experimental Farm, University of Virginia, tested the beetles in an enclosed Y-tube apparatus so that the insect could choose which branch to take. Researchers collected the insects from pumpkin and squash plants. They tested the insects using buffalo gourd plants, a naturally growing wild gourd that likes semiarid areas.Separate air streams flowed into the two branches of the Y-tube. Choices of air in each tube were ambient filtered air, ambient filtered air plus up to 120 parts per million ozone, ambient filtered air plus volatile organic compounds, or air plus up to 120 parts per billion ozone and volatile organic compounds from the plant. To obtain this mix, or only ozone or volatile organic compounds, that branch flowed either to a plant chamber or ozone generator or both.The researchers tested the insects with all ambient air, with ambient air and ozone, with ambient air and volatile organic compounds, and with ambient air and a mix of ozone and volatile organic compounds. When presented with an ambient air or volatile organic compound airstream, the beetles chose the volatile organic compound tube 80 percent of the time."However, as the ozone levels increased, they chose the path to the flower less frequently," said Fuentes. "By the time the mix contained 80 parts per billion ozone, the beetles showed no preference for either tube."The researchers also tested the beetles with volatile organic compounds and a mix of volatile organic compounds and ozone. At low ozone levels, the insects showed no preference, but as ozone levels increased, the insects increasingly preferred the ozone-free path. At 80 parts per billion, the beetles chose the volatile organic compounds without ozone significantly more often than the ozonized mixture.While one might think that higher ozone levels in the lower atmosphere would improve crops because predator insects would be unable to find their hosts, the additional ozone would also interfere with mutualistic insect plant responses such as pollination.The National Science Foundation supported this research.

Ozone Holes

March 11, 2013

https://www.sciencedaily.com/releases/2013/03/130311173917.htm

Causes of 2011 Arctic ozone hole determined

A combination of extreme cold temperatures, human-made chemicals and a stagnant atmosphere were behind what became known as the Arctic ozone hole of 2011, a new NASA study finds.

Even when both poles of the planet undergo ozone losses during the winter, the Arctic's ozone depletion tends to be milder and shorter-lived than the Antarctic's. This is because the three key ingredients needed for ozone-destroying chemical reactions -- chlorine from human-made chlorofluorocarbons (CFCs), frigid temperatures and sunlight -- are not usually present in the Arctic at the same time: the northernmost latitudes are generally not cold enough when the sun reappears in the sky in early spring. Still, in 2011, ozone concentrations in the Arctic atmosphere were about 20 percent lower than its late winter average.The new study shows that, while chlorine in the Arctic stratosphere was the ultimate culprit of the severe ozone loss of winter of 2011, unusually cold and persistent temperatures also spurred ozone destruction. Furthermore, uncommon atmospheric conditions blocked wind-driven transport of ozone from the tropics, halting the seasonal ozone resupply until April."You can safely say that 2011 was very atypical: In over 30 years of satellite records, we hadn't seen any time where it was this cold for this long," said Susan E. Strahan, an atmospheric scientist at NASA Goddard Space Flight Center in Greenbelt, Md., and main author of the new paper, which was recently published in the "Arctic ozone levels were possibly the lowest ever recorded, but they were still significantly higher than the Antarctic's," Strahan said. " There was about half as much ozone loss as in the Antarctic and the ozone levels remained well above 220 Dobson units, which is the threshold for calling the ozone loss a 'hole' in the Antarctic -- so the Arctic ozone loss of 2011 didn't constitute an ozone hole."The majority of ozone depletion in the Arctic happens inside the so-called polar vortex: a region of fast-blowing circular winds that intensify in the fall and isolate the air mass within the vortex, keeping it very cold.Most years, atmospheric waves knock the vortex to lower latitudes in later winter, where it breaks up. In comparison, the Antarctic vortex is very stable and lasts until the middle of spring. But in 2011, an unusually quiescent atmosphere allowed the Arctic vortex to remain strong for four months, maintaining frigid temperatures even after the sun reappeared in March and promoting the chemical processes that deplete ozone.The vortex also played another role in the record ozone low."Most ozone found in the Arctic is produced in the tropics and is transported to the Arctic," Strahan said. "But if you have a strong vortex, it's like locking the door -- the ozone can't get in."To determine whether the mix of human-made chemicals and extreme cold or the unusually stagnant atmospheric conditions was primarily responsible for the low ozone levels observed, Strahan and her collaborators used an atmospheric chemistry and transport model (CTM) called the Global Modeling Initiative (GMI) CTM. The team ran two simulations: one that included the chemical reactions that occur on polar stratospheric clouds, the tiny ice particles that only form inside the vortex when it's very cold, and one without. They then compared their results to real ozone observations from NASA's Aura satellite.The results from the first simulation reproduced the real ozone levels very closely, but the second simulation showed that, even if chlorine pollution hadn't been present, ozone levels would still have been low due to lack of transport from the tropics. Strahan's team calculated that the combination of chlorine pollution and extreme cold temperatures were responsible for two thirds of the ozone loss, while the remaining third was due to the atypical atmospheric conditions that blocked ozone resupply.Once the vortex broke down and transport from the tropics resumed, the ozone concentrations rose quickly and reached normal levels in April 2011.Strahan, who now wants to use the GMI model to study the behavior of the ozone layer at both poles during the past three decades, doesn't think it's likely there will be frequent large ozone losses in the Arctic in the future."It was meteorologically a very unusual year, and similar conditions might not happen again for 30 years," Strahan said. "Also, chlorine levels are going down in the atmosphere because we've stopped producing a lot of CFCs as a result of the Montreal Protocol. If 30 years from now we had the same meteorological conditions again, there would actually be less chlorine in the atmosphere, so the ozone depletion probably wouldn't be as severe."

Ozone Holes

March 11, 2013

https://www.sciencedaily.com/releases/2013/03/130311123933.htm

Ground-level ozone falling faster than model predicted

There is good news and better news about ground-level ozone in American cities. While dangerous ozone levels have fallen in places that clamp down on emissions from vehicles and industry, a new study from Rice University suggests that a model widely used to predict the impact of remediation efforts has been too conservative.

Particularly in Northeastern cities, ozone levels dropped even beyond what was anticipated by cutting emissions of nitrogen oxides (NOx) from 2002 to 2006. The study published online by the journal Atmospheric Environment suggests the Community Multiscale Air Quality (CMAQ) model misjudged the reduction in ozone by 20 to 60 percent."The models have been underpredicting how much benefit we get from controlling NOx emissions in some instances," said Daniel Cohan, an assistant professor of civil and environmental engineering and an author of the study with Rice graduate student Wei Zhou and Sergey Napelenok, a scientist in the Environmental Protection Agency's Atmospheric Modeling and Analysis Division."Following major controls of NOx, ozone has come down more quickly than anticipated," Cohan said. "This is good news. But it also poses a challenge because states rely upon models to predict whether they'll attain ozone standards in the future. If the models have key uncertainties that affect their responsiveness, that can affect the states' control strategies."Ozone is not emitted directly but instead forms near the ground from precursor emissions of NOx and hydrocarbons. Modeling of this complex chemistry is important to help states comply with federal standards for ozone, which now stand at 75 parts per billion (ppb) and may be tightened by the Obama administration. A recent Rice study showed a positive correlation between high ozone levels and cardiac arrest.In 2002, the EPA implemented a cap-and-trade program known as the NOx SIP Call to curtail emissions of ozone-forming NOx from industries in Eastern states. The dramatic reduction in emissions over the subsequent four years provided a real-world experiment for the researchers to test how well computer models predict improvements in air quality."We found that even when we tried to model things with the best available emissions and the best available meteorology, we still had a gap, especially in the Northeast states, that couldn't be explained," he said.In the SIP Call regions, the researchers found the simulated drop in ozone was 4.6 ppb, while the observed drop was 8 ppb, a significant difference. Faster-than-expected reductions in NOx emissions may explain some but not all of that gap. The remaining gap may result from inaccuracies in how the model represents the chemistry and transport of air pollutants, Cohan said."How ozone responds to changes in NOx and hydrocarbons is a nonlinear chemistry," Cohan said. "So it's certainly possible that even the best models could be slightly inaccurate in defining those relationships. It tells us that, as modelers, we need to revisit the formulations, especially the chemistry."While it may be preferable for models to be a bit conservative rather than too aggressive in predicting ozone improvements, Cohan said, the models are intended to represent air pollution as accurately as possible. A study by Cohan's research group last year showed that regulatory modeling by states tended to slightly under-predict the ozone reductions that were actually achieved."The goal of everyone in the process is to reach attainment in the most cost-effective manner possible, and we need accurate models to inform those decisions," Cohan said.The National Science Foundation funded the study through a CAREER grant to Cohan.

Ozone Holes

March 11, 2013

https://www.sciencedaily.com/releases/2013/03/130311091313.htm

Ozone layer above North Pole expected to recover by end of century

Good news for the ozone layer above the Arctic. The Montreal Protocol is showing effects: according to recent measurements, the ozone layer over the North Pole should recover by the end of the century. This is one of the main findings of the EU project RECONCILE, which was completed in February 2013. Scientists from Jülich and their colleagues from 35 research institutions and universities in 14 countries spent four years investigating the chemical process of ozone depletion. Their findings verified once again that chlorine compounds are indeed responsible for this. The scientists used the new insights to improve existing climate models. These models facilitate more reliable predictions on how the ozone layer will develop in future and on the possible consequences of climate change for the stratosphere.

"Even if the ozone layer recovers, climate change could alter the underlying conditions. This is yet another reason to reduce greenhouse gas emissions and stop climate change," emphasizes environmental chemist Dr. Marc von Hobe from Forschungszentrum Jülich, which coordinated RECONCILE. Climate change could alter the temperature, circulation patterns and chemical composition in the stratosphere. This also influences the ozone layer, which in turn has a bearing on temperature. Furthermore, possible ventures to mitigate climate change could have a negative impact on the ozone layer. One example is the so-called Geoengineering. The term describes the use of technological means to intervene in the geochemical or biogeochemical processes of Earth.In the Montreal Protocol, signed in 1987, more than 190 countries vowed to reduce the emission of chlorine containing chemicals such as chlorofluorocarbons (CFCs). A study published around six years ago indirectly called into question the role of CFCs and the Protocol. "In the project, we successfully answered some of the open questions regarding ozone loss, and we demonstrated that besides the destruction caused by chlorine, no additional chemical mechanisms play a decisive role," says Marc von Hobe. Analyses of air samples at the University of East Anglia and the University of Frankfurt as part of the project showed a clear decrease in stratospheric chlorine. Although these compounds remain in the atmosphere longer than previously thought, the scientists expect the ozone layer to recover by the end of the century.This forecast remains unaffected by incidents such as at the beginning of 2011 when the scientists observed the most severe ozone depletion above the North Pole yet. The decisive factor two years ago was an unusually long Arctic winter. Ozone is only depleted under very cold conditions. During the polar night, the polar vortex develops -- a sort of closed system with very cold air, which warmer air masses from the south cannot penetrate. Polar stratospheric clouds (PSCs) form in this vortex at temperatures below -80 °C. On their surfaces, a series of chlorine reactions is initiated that ultimately lead to ozone depletion. The longer the very cold conditions last, the more ozone is destroyed. Only when the polar vortex breaks down in spring can the ozone layer recover.When they investigated these processes in more detail, the RECONCILE researchers unearthed a number of surprises. For example, scientists from Jülich showed that surface reactions also occur very efficiently on liquid aerosols in the air. "For chlorine chemistry, the formation of PSCs is not as important as the temperature. Theoretically, the reactions can occur anywhere where it is cold enough and sufficient chlorine is present," explains Tobias Wegner, who wrote a PhD thesis on aerosol particles and chlorine activation at Forschungszentrum Jülich. However, PSCs still play an important role in ozone depletion. Nitrogen compounds, which react with chlorine compounds to stop the ozone depletion process at the end of the winter, are bound in PSC particles and fall downwards due to gravity. Therefore, chlorine reactions can continue right into spring. "The findings of the project have completely altered our understanding of these clouds. We learned that PSCs can form much more rapidly and at higher temperatures than we thought," says Prof. Tom Peter from ETH Zurich.Scientists from the Max-Planck-Institute for Chemistry, Johannes Gutenberg University Mainz and TU Darmstadt discovered an unexpectedly wide range of particles in their samples. These particles presumably descend from higher stratospheric layers into the polar vortex and contain metals, silicates, black carbon, etc. The origin of these particles is currently being investigated by a group at Mainz as part of the project entitled "In situ experiments on the chemical composition of high-altitude aerosols and clouds in the tropical upper troposphere and lower stratosphere" (EXCATRO), which was awarded an ERC Advanced Grant by the EU.With regard to another point, the scientists were able to put some of our worries to rest: after the record Arctic winter, there were fears of a dramatic increase in UV radiation in the northern hemisphere. "Although we did find elevated values, they were not nearly as high as would be required to considerably increase the risk of skin cancer," says Marc von Hobe.

Ozone Holes

February 25, 2013

https://www.sciencedaily.com/releases/2013/02/130225153126.htm

Clues to climate cycles dug from South Pole snow pit

Particles from the upper atmosphere trapped in a deep pile of Antarctic snow hold clear chemical traces of global meteorological events, a team from the University of California, San Diego and a colleague from France have found.

Anomalies in oxygen found in sulfate particles coincide with several episodes of the world-wide disruption of weather known as El Niño and can be distinguished from similar signals left by the eruption of huge volcanoes, the team reports in the early online edition of the "Our ability to link of reliable chemical signatures to well-known events will make it possible to reconstruct similar short-term fluctuations in atmospheric conditions from the paleohistory preserved in polar ice," said Mark Thiemens, Dean of the Division of Physical Sciences and professor of chemistry and biochemistry, who directed the research and dug up much of the snow.Thiemens, graduate student Justin McCabe and colleague Joel Savarino of Laboratoire de Glaciologie et Géophysique de l'Environnment in Grenoble, France, excavated a pit 6 meters deep in the snow near the South Pole, with shovels."At an elevation of 10,000 feet and 55 degrees below zero, this was quite a task," Thiemens said. Their efforts exposed a 22 year record of snowfall, a pileup of individual flakes, some of which crystallized around particles of sulfate that formed in the tropics.Atmospheric sulfates form when sulfur dioxide -- one sulfur and two oxygen molecules -- mixes with air and gains two more oxygen molecules. This can happen a number of different ways, some of which favor the addition of variant forms of oxygen, or isotopes, with and extra neutron or two, previous work by Thiemens's group has shown.Unlike polar ice, which compresses months of precipitation so tightly that resolution is measured in years, relatively fluffy snow allowed the team to resolve this record of atmospheric chemistry on a much finer scale."That was key," said Robina Shaheen, a project scientist in Thiemen's research group who led the chemical analysis. "This record was every six months. That high resolution made it clear we can trace a seasonal event such as ENSO."ENSO, the El Niño Southern Oscillation, is a complex global phenomenon that begins when trade winds falter allowing piled up in the tropical western Pacific to slosh toward South America in a warm stream that alters marine life crashing fisheries off Peru and Chile, and disrupts patterns of rainfall leaving parts of the planet drenched and others parched.The warmed air above the sea surface lifts sulfur dioxide high into the stratosphere, where it's oxidized by ozone, which imparts a distinctly different, anomalous pattern of oxygen variants to the resulting sulfate particles.In the Antarctic snow samples, the chemists found traces of these oxygen anomalies in sulfates trapped within layers of snow that fell during strong El Niño seasons.Volcanoes too can shoot sulfur compounds high into the atmosphere where they react with ozone to produce sulfates with oxygen anomalies. Three large volcanoes, El Chichón, Pinatubo and Cerro Hudson, erupted over the course of this time sample, which stretched from 1980 to 2002 and encompassed three ENSO events as well.

Ozone Holes

February 17, 2013

https://www.sciencedaily.com/releases/2013/02/130217134200.htm

Links between ozone levels and cardiac arrest analyzed

Researchers at Rice University in Houston have found a direct correlation between out-of-hospital cardiac arrests and levels of air pollution and ozone. Their work has prompted more CPR training in at-risk communities.

Rice statisticians Katherine Ensor and Loren Raun announced their findings February 18 at the American Association for the Advancement of Science (AAAS) conference in Boston. Their research, based on a massive data set unique to Houston, is due to be published in the American Heart Association journal At the same AAAS symposium, Rice environmental engineer Daniel Cohan discussed how uncertainties in air-quality models might impact efforts to achieve anticipated new ozone standards by the U.S. Environmental Protection Agency.Given that the American Lung Association has ranked Houston eighth in the United States for high-ozone days, the Rice researchers set out to see if there is a link between ambient ozone levels and cardiac arrest. Ensor is a professor and chair of Rice's Department of Statistics, and Raun is a research professor in Rice's Department of Statistics.For the new study, the authors analyzed eight years' worth of data drawn from Houston's extensive network of air-quality monitors and more than 11,000 concurrent out-of-hospital cardiac arrests (OHCA) logged by Houston Emergency Medical Services (EMS). They found a positive correlation between OHCAs and exposure to both fine particulate matter (airborne particles smaller than 2.5 micrograms) and ozone.The researchers found that a daily average increase in particulate matter of 6 micrograms per day over two days raised the risk of OHCA by 4.6 percent, with particular impact on those with pre-existing (and not necessarily cardiac-related) health conditions. Increases in ozone level were similar, but on a shorter timescale: Each increase of 20 parts per billion over one to three hours also increased OHCA risk, with a peak of 4.4 percent. Peak-time risks from both pollutants rose as high as 4.6 percent. Relative risks were higher for men, African-Americans and people over 65.For the study, OHCA events were defined as cases where EMS personnel performed chest compressions. Ensor and Raun noted the patients died in more than 90 percent of the cases, which occurred more during the hot summer months (55 percent of total cases).The researchers also looked at the effects of nitrogen dioxide, sulfur dioxide and carbon monoxide levels, none of which were found to impact the occurrence of OHCA.The work is expected to help Houston EMS fine-tune its deployment of personnel and equipment and provide early warnings to health officials and the public when weather and/or incidents warrant an alert for high ozone levels in specific areas, Ensor said.Co-author David Persse, Houston Fire Department EMS physician director and a public-health authority for the city, said it's long been thought by EMS workers that certain types of air pollution, including ozone, have significant negative effects on cardiac and respiratory health. "But this mathematically and scientifically validates what we know," he said.Houston is already acting upon the results."The city has targeted educational resources to at-risk communities, where they're now doing intensive bystander CPR training," Raun said. Early intervention is seen as critical, as the chance of survival for a person suffering cardiac arrest drops 10 percent for every minute he or she is left unattended. She said statistics show one life is saved for every 26 to 36 people who receive cardiopulmonary resuscitation from a bystander.Houston's effort is part of a range of interventions to mitigate the consequences of poor air quality days, though none are substitutes for the primary strategy of improving air quality, according to the city's Health and Human Services Department.Cohan's talk focused on uncertainties in estimating the health benefits that will result from efforts to control ozone pollution. Ozone itself cannot be controlled, he said, as it forms from several precursors. Cohan's research has shown that reducing nitrogen oxide emissions is typically the most effective way to control summertime peak afternoon ozone, but may be less effective than hydrocarbon emission reductions at other times.Ozone standards focus on peak conditions, but some epidemiological studies show that substantial health benefits can also result from reducing ozone at other times, he said. Thus, emission-control strategies aimed solely at achieving regulatory standards may not yield as great a health benefit as strategies that reduce ozone year-round. This research has important implications as states aim to attain national ozone standards. The standards are now set at 75 parts per billion (ppb), but the EPA is considering tightening them to a level in the 60-70 ppb range.A 2012 study by Raun and Ensor published by Rice's Baker Institute for Public Policy determined that, overall, the current EPA standard for ozone serves its purpose, while the particulate standard of 35 micrograms per cubic meter does not."The bottom-line goal is to save lives," Ensor said. "We'd like to contribute to a refined warning system for at-risk individuals. Blanket warnings about air quality may not be good enough."At the same time, we want to enhance our understanding of the health cost of pollution -- and celebrate its continuing reduction."The Houston Endowment and city of Houston funded the study led by Ensor, Raun and Persse. Arturo Blanco, chief of the Bureau of Pollution Control and Prevention, Houston Department of Health and Human Services, supported the research.

Ozone Holes

February 6, 2013

https://www.sciencedaily.com/releases/2013/02/130206185852.htm

One in 20 cases of pre-eclampsia may be linked to air pollutant

One in every 20 cases of the serious condition of pregnancy, pre-eclampsia, may be linked to increased levels of the air pollutant ozone during the first three months, suggests a large study published in the online journal

Mothers with asthma may be more vulnerable, the findings indicate.Pre-eclampsia is characterised by raised blood pressure and the presence of protein in the urine during pregnancy. It can cause serious complications, if left untreated.The authors base their findings on almost 121,000 singleton births in Greater Stockholm, Sweden, between 1998 and 2006; national data on the prevalence of asthma among the children's mothers; and levels of the air pollutants ozone and vehicle exhaust (nitrogen oxide) in the Stockholm area.There's a growing body of evidence pointing to a link between air pollution and premature birth, say the authors, while pregnant women with asthma are more likely to have pregnancy complications, including underweight babies and pre-eclampsia.In all, 4.4% of the pregnancies resulted in a premature birth and the prevalence of pre-eclampsia was 2.7%.There was no association between exposure to levels of vehicle exhaust and complications of pregnancy, nor were any associations found for any air pollutants and babies that were underweight at birth.But there did seem to be a link between exposure to ozone levels during the first three months of pregnancy and the risk of premature birth (delivery before 37 weeks) and pre-eclampsia, after adjusting for factors likely to influence the results and seasonal variations in air pollutants, although not spatial variations in exposure.Each rose by 4% for every 10 ug/m3 rise in ambient ozone during this period, the analysis indicated.Mothers with asthma were 25% more likely to have a child born prematurely and 10% more likely to have pre-eclampsia than mums without this condition.Asthma is an inflammatory condition and ozone may therefore have worsened respiratory symptoms and systemic inflammation, so accounting for the larger increase in the risk of premature birth among the mums with asthma, suggest the authors.But after taking account of the mother's age, previous births, educational attainment, ethnicity, asthma, season and year of conception, the authors calculated that one in every 20 (5%) cases of pre-eclampsia were linked to ozone levels during early pregnancy.

Ozone Holes

January 31, 2013

https://www.sciencedaily.com/releases/2013/01/130131144339.htm

Ozone depletion trumps greenhouse gas increase in jet-stream shift

Depletion of Antarctic ozone is a more important factor than increasing greenhouse gases in shifting the Southern Hemisphere jet stream in a southward direction, according to researchers at Penn State.

"Previous research suggests that this southward shift in the jet stream has contributed to changes in ocean circulation patterns and precipitation patterns in the Southern Hemisphere, both of which can have important impacts on people's livelihoods," said Sukyoung Lee, professor of meteorology.According to Lee, based on modeling studies, both ozone depletion and greenhouse gas increase are thought to have contributed to the southward shift of the Southern Hemisphere jet stream, with the former having a greater impact. B, but until now, no one has been able to determine the extent to which each of these two forcings has contributed to the shift using observational data."Understanding the differences between these two forcings is important in predicting what will happen as the ozone hole recovers," she said. "The jet stream is expected to shift back toward the north as ozone is replenished, yet the greenhouse-gas effect could negate this." Lee and her colleague, Steven Feldstein, professor of meteorology, developed a new method to distinguish between the effects of the two forcings. The method uses a cluster analysis to investigate the effects of ozone and greenhouse gas on several different observed wind patterns."When most people look at ozone and greenhouse gases, they focus on one wind pattern, but my previous research suggests that, by looking at several different but similar patterns, you can learn more about what is really happening," said Feldstein.In their study, the researchers analyzed four wind patterns. The first wind pattern corresponded to an equatorwarda shift of the midlatitude westerlies toward the equator. T; the second pattern also described an equatorward shift, but included a strong tropical component. T; the third pattern corresponded to a poleward shift of the westerlies toward the South Pole with a weakening in the maximum strength of the jet; and the. The fourth pattern corresponded to a smaller poleward jet shift with a strong tropical component.In addition to their novel inclusion of more than one wind pattern in their analysis, the scientists investigated the four wind patterns at very short time scales."Climate models are usually run for many years; they don't look at the day-to-day weather," said Feldstein. "But we learned that the four wind patterns fluctuate over about 10 days, so they change on a time scale that is similar to daily weather. This realization means that by taking into account fluctuations associated with the daily weather, it will be easier to test theories about the mechanism by which ozone and greenhouse gases influence the jet stream."The researchers used an algorithm to examine the relationship between daily weather patterns and the four wind patterns. They found that the first wind pattern -- which corresponded to an equatorward shift of the midlatitude westerlies -- was associated with greenhouse gases. They also found that the third pattern -- which corresponded to a poleward shift of the westerlies -- was associated with ozone. The other two wind patterns were unrelated to either of the forcings. The researchers found that a long-term decline in the frequency of the first pattern and a long-term increase in the frequency of the third pattern can explain the changes in the Southern Hemisphere jet stream."Ozone had the bigger impact on the change in the position of the jet stream," said Lee. "The opposite is likely true for the Northern Hemisphere; we think that ozone has a limited influence on the Northern Hemisphere. Understanding which of these forcings is most important in certain locations may help policy makers as they begin to plan for the future."In addition to finding that ozone is more important than greenhouse gases in influencing the jet-stream shift, the scientists also found evidence for a mechanism by which greenhouse gases influence the jet-stream shift. They learned that greenhouse gases may not directly influence the jet-stream shift, but rather may indirectly influence the shift by changing tropical convection, or the vertical transfer of heat in large-scale cloud systems, which, in turn, influences the jet shift. The researchers currently are further examining this and other possible mechanisms for how greenhouse gases and ozone influence the jet stream as well as Antarctic sea ice.The results will appear in the Feb. 1 issue of the journal "Not only are the results of this paper important for better understanding climate change, but this paper is also important because it uses a new approach to try to better understand climate change; it uses observational data on a short time scale to try to look at cause and effect, which is something that is rarely done in climate research," said Feldstein. "Also, our results are consistent with climate models, so this paper provides support that climate models are performing well at simulating the atmospheric response to ozone and greenhouse gases."

Ozone Holes

January 31, 2013

https://www.sciencedaily.com/releases/2013/01/130131144106.htm

Ozone thinning has changed ocean circulation

A hole in the Antarctic ozone layer has changed the way that waters in the southern oceans mix, a situation that has the potential to alter the amount of CO

In a paper published in this week's issue of the journal"This may sound entirely academic, but believe me, it's not," said Waugh, of the Morton K. Blaustein Department of Earth and Planetary Sciences at Johns Hopkins' Krieger School of Arts and Sciences. "This matters because the southern oceans play an important role in the uptake of heat and carbon dioxide, so any changes in southern ocean circulation have the potential to change the global climate."Waugh's team used measurements taken from the early 1990s to the mid-to-late 2000s of the amount of a chemical compound known as "chlorofluorocarbon-12," or CFC-12, in the southern oceans. CFC-12 was first produced commercially in the 1930s and its concentration in the atmosphere increased rapidly until the 1990s when it was phased out by the Montreal Protocol on substances that deplete the ozone layer. (Prior to the Montreal Protocol, CFC-12 was used in products such as aerosol hairsprays and refrigerants and in air conditioning systems.)From those ocean measurements, Waugh's team was able to infer changes in how rapidly surface waters have mixed into the depths of the southern oceans. Because they knew that concentrations of CFCs at the ocean surface increased in tandem with those in the atmosphere, they were able to surmise that the higher the concentration of CFC-12 deeper in the ocean, the more recently those waters were at the surface.The inferred age changes -- "younger" in the subtropics, "older" nearer the South Pole -- are consistent with the observed intensification of surface westerly winds, which have occurred primarily because of the Antarctic ozone hole, suggesting that stratospheric ozone depletion is the primary cause of the changes in ocean ventilation. As stratospheric ozone recovers over the next 50 years, the changes in ventilation may slow or reverse. The impact of continued increases in greenhouse gases in the atmosphere will also need to be considered, however. The combined impact of the two factors on the southern oceans' ventilation and uptake of heat and carbon is an open question.Also on the research team were collaborators Francois Primeau of the University of California, Irvine; Tim Devries of the University of California, Los Angeles; and Mark Holzer of the University of New South Wales and Columbia University. Funding for the study was provided by the National Science Foundation and the Australian Research Council.

Ozone Holes

January 22, 2013

https://www.sciencedaily.com/releases/2013/01/130122111835.htm

NASA ozone study may benefit air standards, climate

A new NASA-led study finds that when it comes to combating global warming caused by emissions of ozone-forming chemicals, location matters.

Ozone is both a major air pollutant with known adverse health effects and a greenhouse gas that traps heat from escaping Earth's atmosphere. Scientists and policy analysts are interested in learning how curbing the emissions of these chemicals can improve human health and also help mitigate climate change.Research scientists Kevin Bowman of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and Daven Henze of the University of Colorado, Boulder, set out to quantify, down to areas the size of large metropolitan regions, how the climate-altering impacts of these chemical emissions vary around the world. The chemicals, which are produced from sources such as planes, factories and automobiles, are converted to ozone in the presence of sunlight and subsequently transported by wind around our planet. Among these chemicals are nitrogen dioxide, carbon monoxide and non-methane hydrocarbons.By combining satellite observations of how much heat ozone absorbs in Earth's atmosphere with a model of how chemicals are transported in the atmosphere, the researchers discovered significant regional variability -- in some places by more than a factor of 10 -- in how efficiently ozone trapped heat in Earth's atmosphere, depending upon where the ozone-forming chemical emissions were located. This variability was found within individual continents and even among different regions with similar emission levels within individual countries. High-latitude regions such as Europe had a smaller impact than lower-latitude regions like North America. Ozone was observed to be a more efficient greenhouse gas over hot regions like the tropics or relatively cloud-free regions like the Middle East. The satellite data were collected by the Tropospheric Emission Spectrometer instrument on NASA's Aura spacecraft."When it comes to reducing ozone levels, emission reductions in one part of the world may drive greenhouse warming more than a similar level of emission reductions elsewhere," said Bowman, lead author of the study, published recently in the journal Variations in chemicals that lead to the production of ozone are driven by industry and human population. For example, the U.S. Northeast has much higher ozone precursor emission levels than, say, Wisconsin."We show that, for example, even though Chicago has a level of ozone precursor emissions three times larger than the levels in Atlanta, reducing emissions by 10 percent in the Atlanta region has the same impact on climate as reducing emissions by 10 percent in Chicago," Bowman added. "This is because Atlanta is a much more efficient place than Chicago for affecting climate through ozone."The researchers found that the top 15 regional contributors to global ozone greenhouse gas levels were predominantly located in China and the United States, including the regions that encompass New Orleans, Atlanta and Houston.Bowman and Henze found considerable variability in how different types of emissions contribute to ozone's greenhouse gas effect. For example, compared to all nitrogen dioxide emissions -- both human-produced and natural -- industrial and transportation sources make up a quarter of the total greenhouse gas effect, whereas airplanes make up only one percent. They also found that nitrogen dioxide contributes about two-thirds of the ozone greenhouse gas effect compared to carbon monoxide and non-methane hydrocarbons.Bowman said the research suggests that solutions to improve air quality and combat climate change should be tailored for the regions in which they are to be executed."One question that's getting a lot of interest in policy initiatives such as the United Nations' Environment Programme Climate and Clean Air Coalition is controlling short-lived greenhouse gases like methane and ozone as part of a short-term strategy for mitigating climate change," Bowman said. "Our study could enable policy researchers to calculate the relative health and climate benefits of air pollution control and pinpoint where emission reductions will have the greatest impacts. This wasn't really possible to do at these scales before now. This is particularly important in developing countries like China, where severe air pollution problems are of greater concern to public officials than climate change mitigation in the short term.""Our study is an important step forward in this field because we've built a special model capable of looking at the effects of location at a very high resolution," said Henze. "The model simulations are based upon actual observations of ozone warming effects measured by NASA's Tropospheric Emission Spectrometer satellite instrument. This is the first time we've been able to separate observed heat trapping due to ozone into its natural versus human sources, and even into specific types of human sources, such as fossil fuels versus biofuels. This information can be used to mitigate climate change while improving air quality."For more information on TES, visit: The California Institute of Technology in Pasadena manages JPL for NASA.

Ozone Holes

January 13, 2013

https://www.sciencedaily.com/releases/2013/01/130113144812.htm

Gas that triggers ozone destruction revealed

Scientists at the Universities of York and Leeds have made a significant discovery about the cause of the destruction of ozone over oceans.

They have established that the majority of ozone-depleting iodine oxide observed over the remote ocean comes from a previously unknown marine source.The research team found that the principal source of iodine oxide can be explained by emissions of hypoiodous acid (HOI) – a gas not yet considered as being released from the ocean – along with a contribution from molecular iodine (ISince the 1970s when methyl iodide (CHThis new research, which is published in The scientists quantified gaseous emissions of inorganic iodine following the reaction of iodide with ozone in a series of laboratory experiments. They showed that the reaction of iodide with ozone leads to the formation of both molecular iodine and hypoiodous acid. Using laboratory models, they show that the reaction of ozone with iodide on the sea surface could account for around 75 per cent of observed iodine oxide levels over the tropical Atlantic Ocean.Professor Lucy Carpenter, of the Department of Chemistry at York, said: “Our laboratory and modelling studies show that these gases are produced from the reaction of atmospheric ozone with iodide on the sea surface interfacial layer, at a rate which is highly significant for the chemistry of the marine atmosphere.“Our research reveals an important negative feedback for ozone – a sort of self-destruct mechanism. The more ozone there is, the more gaseous halogens are created which destroy it. The research also has implications for the way that radionucleides of iodine in seawater, released into the ocean mainly from nuclear reprocessing facilities, can be re-emitted into the atmosphere.”Professor John Plane, from the University of Leeds’ School of Chemistry, said: “This mechanism of iodine release into the atmosphere appears to be particularly important over tropical oceans, where measurements show that there is more iodide in seawater available to react with ozone. The rate of the process also appears to be faster in warmer water. The negative feedback for ozone should therefore be particularly important for removing ozone in the outflows of pollution from major cities in the coastal tropics.” The research was funded by the UK Natural Environment Research Council SOLAS (Surface Ocean Lower Atmosphere) programme.

Ozone Holes

January 9, 2013

https://www.sciencedaily.com/releases/2013/01/130109175412.htm

NASA chases climate change clues into the stratosphere

Starting this month, NASA will send a remotely piloted research aircraft as high as 65,000 feet over the tropical Pacific Ocean to probe unexplored regions of the upper atmosphere for answers to how a warming climate is changing Earth.

The first flights of the Airborne Tropical Tropopause Experiment (ATTREX), a multi-year airborne science campaign with a heavily instrumented Global Hawk aircraft, will take off from and be operated by NASA's Dryden Flight Research Center at Edwards Air Force Base in California. The Global Hawk is able to make 30-hour flights.Water vapor and ozone in the stratosphere can have a large impact on Earth's climate. The processes that drive the rise and fall of these compounds, especially water vapor, are not well understood. This limits scientists' ability to predict how these changes will influence global climate in the future. ATTREX will study moisture and chemical composition in the upper regions of the troposphere, the lowest layer of Earth's atmosphere. The tropopause layer between the troposphere and stratosphere, 8 miles to 11 miles above Earth's surface, is the point where water vapor, ozone and other gases enter the stratosphere.Studies have shown even small changes in stratospheric humidity may have significant climate impacts. Predictions of stratospheric humidity changes are uncertain because of gaps in the understanding of the physical processes occurring in the tropical tropopause layer. ATTREX will use the Global Hawk to carry instruments to sample this layer near the equator off the coast of Central America."The ATTREX payload will provide unprecedented measurements of the tropical tropopause," said Eric Jensen, ATTREX principal investigator at NASA's Ames Research Center in Moffett Field, Calif. "This is our first opportunity to sample the tropopause region during winter in the northern hemisphere when it is coldest and extremely dry air enters the stratosphere."Led by Jensen and project manager Dave Jordan of Ames, ATTREX scientists installed 11 instruments in the Global Hawk. The instruments include remote sensors for measuring clouds, trace gases and temperatures above and below the aircraft, as well as instruments to measure water vapor, cloud properties, meteorological conditions, radiation fields and numerous trace gases around the aircraft. Engineering test flights conducted in 2011 ensured the aircraft and instruments operated well at the very cold temperatures encountered at high altitudes in the tropics, which can reach minus 115 degrees Fahrenheit.Six science flights are planned between Jan. 16 and March 15. The ATTREX team also is planning remote deployments to Guam and Australia in 2014. Scientists hope to use the acquired data to improve global model predictions of stratospheric humidity and composition. The ATTREX team consists of investigators from Ames and three other NASA facilities; the Langley Research Center in Hampton, Va., Goddard Space Flight Center in Greenbelt, Md., and Jet Propulsion Laboratory in Pasadena, Calif. The team also includes investigators from the National Oceanic and Atmospheric Administration, National Center for Atmospheric Research, academia, and private industry.ATTREX is one of the first investigations in NASA's new Venture-class series of low- to moderate-cost projects. The Earth Venture missions are part of NASA's Earth System Science Pathfinder Program managed by Langley. These small, targeted science investigations complement NASA's larger science research satellite missions.For more information about the ATTREX mission, visit: A digital ATTREX press kit is available at:

Ozone Holes

December 18, 2012

https://www.sciencedaily.com/releases/2012/12/121218153241.htm

Ozone levels have sizeable impact on worker productivity

Researchers in the Department of Health Policy and Management at Columbia's Mailman School of Public Health assessed the impact of pollution on agricultural worker productivity using daily variations in ozone levels. Their results show that ozone, even at levels below current air-quality standards in most parts of the world, has significant negative impacts on worker productivity. Their findings suggest that environmental protection is important for promoting economic growth and investing in human capital in contrast to its common portrayal as a tax on producers.

Results of the study are published in the Ozone pollution continues to be a pervasive global issue with much debate over optimal levels. While policy makers routinely note that regulating ozone smog leads to many health benefits like reduced hospitalizations and mortality rates, Matthew Neidell, PhD, associate professor at the Mailman School and principal investigator, set out to investigate whether lower air pollution might also affect job performance. Until this research, there had been no systematic evidence on the direct impact of pollution on worker productivity.The researchers found that a 10 ppb (parts per billion) change in average ozone exposure results in a significant 5.5 percent change in agricultural worker productivity. "These estimates are particularly noteworthy as the U.S. EPA is currently moving in the direction of reducing federal ground-level ozone standards," said Dr.Neidell, PhD. This past September President Obama said he would not support a proposal by the Environmental Protection Agency to tighten the federal ozone standard because it would pose too heavy a burden on businesses, which stunned public health experts and environmentalists.Dr. Neidell also points out that in developing countries where environmental regulations are less strict and agriculture plays a more dominant role in the economy, the effects reported here may have a vast detrimental impact on a country's prosperity.

Ozone Holes

November 21, 2012

https://www.sciencedaily.com/releases/2012/11/121121130939.htm

Unexpected microbes fighting harmful greenhouse gas

The environment has a more formidable opponent than carbon dioxide. Another greenhouse gas, nitrous oxide, is 300 times more potent and also destroys the ozone layer each time it is released into the atmosphere through agricultural practices, sewage treatment and fossil fuel combustion.

Luckily, nature has a larger army than previously thought combating this greenhouse gas -- according to a study by Frank Loeffler, University of Tennessee, Knoxville-Oak Ridge National Laboratory Governor's Chair for Microbiology, and his colleagues.The findings are published in the Nov. 12 edition of the Scientists have long known about naturally occurring microorganisms called denitrifiers, which fight nitrous oxide by transforming it into harmless nitrogen gas. Loeffler and his team have now discovered that this ability also exists in many other groups of microorganisms, all of which consume nitrous oxide and potentially mitigate emissions.The research team screened available microbial genomes encoding the enzyme systems that catalyze the reduction of the nitrous oxide to harmless nitrogen gas.They discovered an unexpected broad distribution of this class of enzymes across different groups of microbes with the power to transform nitrous oxide to innocuous nitrogen gas. Within these groups, the enzymes were related yet evolutionarily distinct from those of the known denitrifiers. Microbes with this capability can be found in most, if not all, soils and sediments, indicating that a much larger microbial army contributes to nitrous oxide consumption."Before we did this study, there was an inconsistency in nitrous oxide emission predictions based on the known processes contributing to nitrous oxide consumption, suggesting the existence of an unaccounted nitrous oxide sink," said Loeffler. "The new findings potentially reconcile this discrepancy."According to Loeffler, the discovery of this microbial diversity and its contributions to nitrous oxide consumption will allow the scientific community to advance its understanding of the ecological controls on global nitrous oxide emissions and to refine greenhouse gas cycle models."This will allow us to better describe and predict the consequences of human activities on ozone layer destruction and global warming," said Loeffler. "Our results imply that the analysis of the typical denitrifier populations provides an incomplete picture and is insufficient to account for or accurately predict the true nitrous oxide emissions."

Ozone Holes

October 30, 2012

https://www.sciencedaily.com/releases/2012/10/121030161523.htm

Ozone's impact on soybean yield: Reducing future losses

People tend to think of ozone as something in the upper atmosphere that protects Earth's surface from UV radiation. At the ground level, however, ozone is a pollutant that damages crops, particularly soybean.

Lisa Ainsworth, a University of Illinois associate professor of crop sciences and USDA Agricultural Research Service plant molecular biologist, said that establishing the exposure threshold for damage is critical to understanding the current and future impact of this pollutant."Most of my research is on measuring the effects of ozone on soybean, determining the mechanisms of response, and then trying to improve soybean tolerance to ozone so that we can improve soybean yields," she explained.Ozone is highly reactive with membranes and proteins and is known to damage the human lung. It also harms plants, slowing photosynthesis and accelerating senescence. As a result, they take in and fix less carbon, reducing yield. Ainsworth said that ground level concentrations of ozone are already high enough to damage crop production."Ozone reacts very quickly once it enters the leaf through the stomata," she explained. "It can form other oxygen radicals and also hydrogen peroxide. Then a series of cascading reactions causes a decrease in photosynthesis, reducing stomata conductance."The plant's response to ozone mimics a hypersensitive response to a pathogen attack. "At quite high concentrations of ozone, you can get leaf bronzing, stippling of the leaves, and necrotic spots," Ainsworth said. "At really high concentrations, you get cell death." The metabolic changes then feed forward to affect plant productivity.Ainsworth's group conducted a two year study in 2009 and 2010 at the Soybean Free Air Concentration Enrichment (SoyFACE) facility at the U of I South Farms. It was the first dose-response experiment to look at ozone and soybean under completely open-air conditions.They investigated the responses of seven different soybean genotypes to eight ozone concentrations. The plants were exposed to ozone concentrations ranging from ambient levels of 38 parts per billion up to 200 parts per billion. "This is quite high, but unfortunately, those kinds of concentrations are what very polluted areas of China and India are looking at today," Ainsworth said.The researchers found that any increase above the ambient concentration was enough to reduce seed yield: roughly half a bushel per acre for each additional part per billion."This is significant," Ainsworth said. "Especially considering that background concentrations of ozone today vary year to year, anywhere from about 38 to 39 parts per billion to about 62. That can be 15 bushels per acre from one year to the next that farmers are losing to ozone." The researchers compared the results of this study, which used modern genotypes, with results from experiments conducted in controlled environments in the 1980s. They found that the responses of the modern genotypes were similar to those of the older genotypes."Breeders haven't inadvertently bred for ozone tolerance in more modern lines," Ainsworth said. "They're still sensitive to ozone, which means that farmers are still subject to these yearly variations in ozone and are losing yield accordingly."Potential increases in background ozone are predicted to increase soybean yield losses by 9 to 19 percent by 2030. Levels were particularly high during this year's growing season because most days were sunny and warm, and thus they were favorable for ozone formation. Peaks on many days exceeded 80 parts per billion, twice the known sensitivity threshold.

Ozone Holes

October 24, 2012

https://www.sciencedaily.com/releases/2012/10/121024164723.htm

2012 Antarctic ozone hole second smallest in 20 years

The average area covered by the Antarctic ozone hole this year was the second smallest in the last 20 years, according to data from NASA and National Oceanic and Atmospheric Administration (NOAA) satellites. Scientists attribute the change to warmer temperatures in the Antarctic lower stratosphere.

The ozone hole reached its maximum size Sept. 22, covering 8.2 million square miles (21.2 million square kilometers), or the area of the United States, Canada and Mexico combined. The average size of the 2012 ozone hole was 6.9 million square miles (17.9 million square kilometers). The Sept. 6, 2000 ozone hole was the largest on record at 11.5 million square miles (29.9 million square kilometers)."The ozone hole mainly is caused by chlorine from human-produced chemicals, and these chlorine levels are still sizable in the Antarctic stratosphere," said NASA atmospheric scientist Paul Newman of NASA's Goddard Space Flight Center in Greenbelt, Md. "Natural fluctuations in weather patterns resulted in warmer stratospheric temperatures this year. These temperatures led to a smaller ozone hole."Atmospheric ozone is no longer declining because concentrations of ozone-depleting chemicals stopped increasing and are now declining.The ozone layer acts as Earth's natural shield against ultraviolet radiation, which can cause skin cancer. The ozone hole phenomenon began making a yearly appearance in the early 1980s. The Antarctic ozone layer likely will not return to its early 1980s state until about 2065, Newman said. The lengthy recovery is because of the long lifetimes of ozone-depleting substances in the atmosphere. Overall atmospheric ozone no longer is declining as concentrations of ozone-depleting substances decrease. The decrease is the result of an international agreement regulating the production of certain chemicals.This year also marked a change in the concentration of ozone over the Antarctic. The minimum value of total ozone in the ozone hole was the second highest level in two decades. Total ozone, measured in Dobson units (DU) reached 124 DU on Oct. 1. NOAA ground-based measurements at the South Pole recorded 136 DU on Oct. 5. When the ozone hole is not present, total ozone typically ranges from 240-500 DU.This is the first year growth of the ozone hole has been observed by an ozone-monitoring instrument on the Suomi National Polar-orbiting Partnership (NPP) satellite. The instrument, called the Ozone Mapping Profiler Suite (OMPS), is based on previous instruments, such as the Total Ozone Mapping Spectrometer (TOMS) and the Solar Backscatter Ultraviolet instrument (SBUV/2). OMPS continues a satellite record dating back to the early 1970s.In addition to observing the annual formation and extent of the ozone hole, scientists hope OMPS will help them better understand ozone destruction in the middle and upper stratosphere with its Nadir Profiler. Ozone variations in the lower stratosphere will be measured with its Limb Profiler."OMPS Limb looks sideways, and it can measure ozone as a function of height," said Pawan K. Bhartia, a NASA atmospheric physicist and OMPS Limb instrument lead. "This OMPS instrument allows us to more closely see the vertical development of Antarctic ozone depletion in the lower stratosphere where the ozone hole occurs."NASA and NOAA have been monitoring the ozone layer on the ground and with a variety of instruments on satellites and balloons since the 1970s. Long-term ozone monitoring instruments have included TOMS, SBUV/2, Stratospheric Aerosol and Gas Experiment series of instruments, the Microwave Limb Sounder, the Ozone Monitoring Instrument, and the OMPS instrument on Suomi NPP. Suomi NPP is a bridging mission leading to the next-generation polar-orbiting environmental satellites called the Joint Polar Satellite System, will extend ozone monitoring into the 2030s.NASA and NOAA have a mandate under the Clean Air Act to monitor ozone-depleting gases and stratospheric depletion of ozone. NOAA complies with this mandate by monitoring ozone via ground and satellite measurements. The NOAA Earth System Research Laboratory in Boulder, Colo., performs the ground-based monitoring. The Climate Prediction Center performs the satellite monitoring.

Ozone Holes

October 18, 2012

https://www.sciencedaily.com/releases/2012/10/121018123306.htm

Ozone affects forest watersheds

U.S. Forest Service and Oak Ridge National Laboratory (ORNL) scientists have found that rising levels of ozone, a greenhouse gas, may amplify the impacts of higher temperatures and reduce streamflow from forests to rivers, streams, and other water bodies. Such effects could potentially reduce water supplies available to support forest ecosystems and people in the southeastern United States.

Impacts of ozone, a global scale pollutant, on forests are not well understood at a large scale. This modeling study indicates that current and projected increases in ozone in the 21st century will likely enhance the negative effects of warming on watersheds, aggravating drought and altering stream flow. Using data on atmospheric water supply and demand and statistical models, researchers with the Forest Service and ORNL were able to show what effects ozone can have on stream flow in dry seasons. Published in the November issue of the journal "From previous studies, we know a lot about ozone's influences on crops and leaves of young trees. However, no studies have investigated the impacts of ozone on water flow in large forested watersheds," says Ge Sun, research hydrologist with the Forest Service Eastern Forest Environmental Threat Assessment Center "Our studies show that ozone has a possible connection in the reduction of streamflow in late summer when flow is generally lowest, particularly in areas with high ozone levels such as the Appalachian Mountains in the Southeast."Researchers developed models based on 18 to 26 years of data and observed streamflow in response to climate and atmospheric chemistry during the growing season. The research team evaluated individual and interactive effects of ozone on late season streamflow for six southeastern forested watersheds ranging in size from 38 acres to more than 3,700 square miles. Estimates of ozone's influence on streamflow ranged from 7 percent in the area of lowest ozone in West Virginia to 23 percent in the areas of highest exposure in Tennessee.The findings from this study along with a wide range of previous field studies challenge assumptions derived from small controlled studies that ozone exposure reduces water loss from trees and forests. The present study of mature forests under moderate ozone exposure shows however those ecosystems may react in a different way than can be predicted by short-range, intensive studies."We're predicting that forests under high ozone conditions will use more water instead of less, as was previously assumed," says Samuel "Sandy" McLaughlin, scientist emeritus from the ORNL Environmental Sciences Division. "The concern is that ozone-induced increases in plant water loss could aggravate drought impacts on forests, and reduce the water available for people and stream life dependent on water flow during the dry seasons."Forest Service and ORNL scientists also collaborated with researchers from the University of Virginia, Lamont Doherty Observatory, and the University of Gothenburg, Sweden.

Ozone Holes

September 19, 2012

https://www.sciencedaily.com/releases/2012/09/120919103614.htm

New screening method identifies 1,200 candidate refrigerants to combat global warming

Researchers at the National Institute of Standards and Technology (NIST) have developed a new computational method for identifying candidate refrigerant fluids with low "global warming potential" (GWP) -- the tendency to trap heat in the atmosphere for many decades -- as well as other desirable performance and safety features.

The NIST effort is the most extensive systematic search for a new class of refrigerants that meet the latest concerns about climate change. The new method was used to identify about 1,200 promising, low-GWP chemicals for further study among some 56,000 that were considered. Only about 60 of these have boiling points low enough to be suitable for common refrigeration equipment, an indication of how difficult it is to identify usable fluids.The ongoing NIST project is a response to U.S. industry interest in a new generation of alternative refrigerants that already are required for use in the European Union.The refrigerants now used in cars and homes are mainly hydrofluorocarbons (HFCs). They were adopted a generation ago in the effort to phase out chlorofluorocarbons (CFCs), which deplete the stratospheric ozone layer. An example is R-134a (1,1,1,2-tetrafluoroethane), which replaced ozone-depleting chemicals in automobile air conditioners and home refrigerators. R-134a now is being phased out in Europe because HFCs remain in the atmosphere for many years, yielding a high GWP. A compound's GWP is defined as the warming potential of one kilogram of the gas relative to one kilogram of carbon dioxide. R-134a has a GWP of 1,430, much higher than the GWP of 150 or less now mandated for automotive use in Europe.Promising low-GWP chemicals include fluorinated olefins, which react rapidly with atmospheric compounds and thus will not persist for long periods."What industry is trying to do is be prepared, because moving from a GWP in the thousands or tens of thousands to a GWP of 150 is an enormous challenge, both economically and technologically," says NIST chemist Michael Frenkel. "We decided to leverage the tools NIST has been developing for the last 15 years to look into the whole slew of available chemicals."The affected industry is huge: The U.S. air conditioning, heating and refrigeration equipment manufacturing industry ships about $30 billion in goods annually, according to the U.S. Bureau of the Census.NIST has extensive experience evaluating alternative refrigerants, having previously helped the refrigeration industry find replacements for CFCs.The new NIST method estimates GWP by combining calculations of a compound's radiative efficiency (a measure of how well it absorbs infrared radiation) and atmospheric lifetime, both derived from molecular structure. Additional filtering is based on low toxicity and flammability, adequate stability, and critical temperature (where the compound's liquid and gas properties converge) in a desirable range. The method was applied to 56,203 compounds and identified 1,234 candidates for further study. The method, which was validated against available literature data, is accurate and fast enough for virtual screening applications. The approach is similar to the large-scale virtual screening and computational design methods for discovering new pharmaceuticals.The screening is the initial stage of a larger study funded by the U.S. Department of Energy. The next step will be to further narrow down the candidates to a couple dozen suitable for detailed investigation in refrigeration cycle modeling.

Ozone Holes

August 20, 2012

https://www.sciencedaily.com/releases/2012/08/120820114041.htm

Extreme weather linked to global warming, Nobel prize-winning scientist says

New scientific analysis strengthens the view that record-breaking summer heat, crop-withering drought and other extreme weather events in recent years do, indeed, result from human activity and global warming, Nobel Laureate Mario J. Molina, Ph.D., said at a conference in Philadelphia on August 20.

Molina, who shared the 1995 Nobel Prize in Chemistry for helping save the world from the consequences of ozone depletion, presented the keynote address at the 244"People may not be aware that important changes have occurred in the scientific understanding of the extreme weather events that are in the headlines," Molina said. "They are now more clearly connected to human activities, such as the release of carbon dioxide ― the main greenhouse gas ― from burning coal and other fossil fuels."Molina emphasized that there is no "absolute certainty" that global warming is causing extreme weather events. But he said that scientific insights during the last year or so strengthen the link. Even if the scientific evidence continues to fall short of the absolute certainly measure, the heat, drought, severe storms and other weather extremes may prove beneficial in making the public more aware of global warming and the need for action, said Molina."It's important that people are doing more than just hearing about global warming," he said. "People may be feeling it, experiencing the impact on food prices, getting a glimpse of what everyday life may be like in the future, unless we as a society take action."Molina, who is with the University of California, San Diego, suggested a course of action based on an international agreement like the Montreal Protocol that phased out substances responsible for the depletion of the ozone layer."The new agreement should put a price on the emission of greenhouse gases, which would make it more economically favorable for countries to do the right thing. The cost to society of abiding by it would be less than the cost of the climate change damage if society does nothing," he said.In the 1970s and 1980s, Molina, F. Sherwood Rowland, Ph.D., and Paul J. Crutzen, Ph.D., established that substances called CFCs in aerosol spray cans and other products could destroy the ozone layer. The ozone layer is crucial to life on Earth, forming a protective shield high in the atmosphere that blocks potentially harmful ultraviolet rays in sunlight. Molina, Rowland and Crutzen shared the Nobel Prize for that research. After a "hole" in that layer over Antarctica was discovered in 1985, scientists established that it was indeed caused by CFCs, and worked together with policymakers and industry representatives around the world to solve the problem. The result was the Montreal Protocol, which phased out the use of CFCs in 1996.Adopted and implemented by countries around the world, the Montreal Protocol eliminated the major cause of ozone depletion, said Molina, and stands as one of the most successful international agreements. Similar agreements, such as the Kyoto Protocol, have been proposed to address climate change. But Molina said these agreements have largely failed.Unlike the ozone depletion problem, climate change has become highly politicized and polarizing, he pointed out. Only a small set of substances were involved in ozone depletion, and it was relatively easy to get the small number of stakeholders on the same page. But the climate change topic has exploded. "Climate change is a much more pervasive issue," he explained. "Fossil fuels, which are at the center of the problem, are so important for the economy, and it affects so many other activities. That makes climate change much more difficult to deal with than the ozone issue."In addition to a new international agreement, other things must happen, he said. Scientists need to better communicate the scientific facts underlying climate change. Scientists and engineers also must develop cheap alternative energy sources to reduce dependence on fossil fuels.Molina said that it's not certain what will happen to Earth if nothing is done to slow down or halt climate change. "But there is no doubt that the risk is very large, and we could have some consequences that are very damaging, certainly for portions of society," he said. "It's not very likely, but there is some possibility that we would have catastrophes."

Ozone Holes

August 10, 2012

https://www.sciencedaily.com/releases/2012/08/120810134105.htm

50-year decline found in some Los Angeles vehicle-related pollutants

In California's Los Angeles Basin, levels of some vehicle-related air pollutants have decreased by about 98 percent since the 1960s, even as area residents now burn three times as much gasoline and diesel fuel. Between 2002 and 2010 alone, the concentration of air pollutants called volatile organic compounds (VOCs) dropped by half, according to a new study by NOAA scientists and colleagues, published in the

"The reason is simple: Cars are getting cleaner," said Carsten Warneke, Ph.D., a NOAA-funded scientist with the Cooperative Institute for Research in Environmental Sciences (CIRES) at the University of Colorado Boulder.VOCs, primarily emitted from the tailpipes of vehicles, are a key ingredient in the formation of ground-level ozone which, at high levels, can harm people's lungs and damage crops and other plants.The magnitude of the drop in VOC levels was surprising, even to researchers who expected some kind of decrease resulting from California's longtime efforts to control vehicle pollution."Even on the most polluted day during a research mission in 2010, we measured half the VOCs we had seen just eight years earlier," Warneke said. "The difference was amazing."The 98 percent drop in VOCs in the last 50 years does not mean that ozone levels have dropped that steeply; the air chemistry that leads from VOCs to ozone is more complex than that. Ozone pollution in the Los Angeles Basin has decreased since the 1960s, but levels still don't meet ozone standards set by the Environmental Protection Agency.Requirements for catalytic converters, use of reformulated fuels less prone to evaporate, and improved engine efficiency of new vehicles have all likely contributed to overall declines in vehicle-related pollution, including VOCs.The improvement in this one measure of air quality in Los Angeles may not surprise many longtime residents, Warneke said. People who lived in the city in the 1960s often couldn't see nearby mountains through the smog; today, they often can.For the new study, Warneke and his colleagues evaluated Los Angeles air quality measurements from three sources: NOAA-led research campaigns in 2002 and 2010, which involved extensive aircraft sampling of the atmosphere; datasets from other intensive field campaigns reaching back five decades; and air quality measurements from the California Air Resources Board monitoring sites, which reach back two to three decades.Overall, VOCs dropped by an average of 7.5 percent per year. "This is essentially the kind of change we would expect, and it is very good to find that it is actually taking place," Warneke said.A few specific VOCs, such as propane and ethane, did not drop as quickly. Those chemicals come from sources other than vehicles, such as the use and production of natural gas. Another recent study led by CIRES and NOAA researchers and published online August 4 in Warneke said that he would expect the decrease in emissions of VOCs by cars to continue in Los Angeles, given that engine efficiency continues to improve and older, more polluting vehicles drop out of the fleet of all vehicles on the road.

Ozone Holes

July 30, 2012

https://www.sciencedaily.com/releases/2012/07/120730094140.htm

Cloud seeds and ozone holes

The destruction of atmospheric ozone can take place within newly forming Polar Stratospheric Clouds (PSCs), which serve as the battleground for humanmade chlorofluorocarbons (CFCs) to attack and destroy ozone. These clouds form when clusters of frozen water "pick up" other atmospheric molecules such as methane, nitrogen oxides, and water molecules, similar to the way a snowball's girth increases as it rolls down a mountainside.

Most previously established atmospheric models have assumed that a straightforward measurement, a geometrical cross section, of the ice particles is sufficient to understandthe particle formation process. However, an international team of scientists has uncovered new evidence that these clusters can attract and capture molecules from a much larger volume than the space the clusters physically occupy.The work is presented in a paper accepted to the AIP's Researchers discovered this discrepancy in expected size by mimicking the growth process of cloud seeds in laboratory experiments performed at the J. Heyrovský Institute of Physical Chemistry, part of the Academy of Sciences of the Czech Republic in Prague. A beam of water clusters was sent through a chamber filled with a typical atmospheric gas such as methane or water vapor, and the team measured how many molecules the clusters picked up as they passed. They found that the clusters were able to pick up molecules even when those molecules did not collide directly with the clusters. Theoretical studies supported these results.The researchers hope their findings will allow for more accurate models to predict the dynamics of ice particle formation in PSCs, which will in turn impact scientists' understanding of atmospheric chemistry processes such as ozone depletion, which increases the amount of harmful ultraviolet light entering Earth's atmosphere from the Sun.

Ozone Holes

July 26, 2012

https://www.sciencedaily.com/releases/2012/07/120726142204.htm

Climate change linked to ozone loss: May result in more skin cancer

For decades, scientists have known that the effects of global climate change could have a potentially devastating impact across the globe, but Harvard researchers say there is now evidence that it may also have a dramatic impact on public health.

As reported in a paper published in the July 27 issue of In the system described by Anderson and his team, water vapor injected into the stratosphere by powerful thunderstorms converts stable forms of chlorine and bromine into free radicals capable of transforming ozone molecules into oxygen. Recent studies have suggested that the number and intensity of such storms are linked to climate changes, Anderson said, which could in turn lead to increased ozone loss and greater levels of harmful UV radiation reaching the Earth's surface, and potentially higher rates of skin cancer."If you were to ask me where this fits into the spectrum of things I worry about, right now it's at the top of the list," Anderson said. "What this research does is connect, for the first time, climate change with ozone depletion, and ozone loss is directly tied to increases in skin cancer incidence, because more ultraviolet radiation is penetrating the atmosphere."Unfortunately, Anderson said, we don't know how this process will evolve over time."We don't know what the development of this has been -- we don't have measurements of this deep convective injection of water into the stratosphere that go back in time," Anderson said."But the best guide for the evolution of this is to look at the research that connects climate change with severe storm intensity and frequency, and it's clear that there is a developing scientific case that the addition of carbon dioxide to the atmosphere is increasing climate change, and in turn driving severe storm intensity and frequency."While it's impossible to know how many skin cancer cases may be related to ozone depletion over the U.S., the link between ozone loss and increased incidence of the disease has been extensively studied, Anderson said."There has been a major effort by the medical community to define the relationship between decreases in ozone and the subsequent increases in skin cancer," he said. "The answer is quite clear -- if you multiply the fractional decrease in ozone protection by about three, you get the increase in skin cancer incidence. There are 1 million new skin cancer cases in the U.S. annually -- it's the most common form of cancer, and it's one that's increasing in spite of all the medical research devoted to it."But it isn't only humans who have to worry about the effects of increased UV radiation.Many crops, particularly staple crops grown for human consumption -- such as wheat, soybeans and corn -- could suffer damage to their DNA, Anderson said.Ironically, Anderson said, the discovery that climate change might be driving ozone loss happened virtually by accident.Though they had worked since the mid-1980s to investigate ozone depletion in the Arctic and Antarctic, by the early-2000s, Anderson's team had turned their attention to climate studies. In particular, they were working to understand how the convective clouds -- updrafts that cause storms to build high into the sky -- contribute to the creation of cirrus clouds."It was in the process of looking at that mechanism that we came to this unexpected observation -- that the convective clouds in these storm systems over the U.S. are reaching far deeper into the stratosphere that we ever expected," Anderson said.While earlier tests performed in the Arctic had demonstrated that water vapor was a key component in creating the "free-radical" compounds that break down ozone, Anderson said the latest finding is much more troubling, because it suggests the process can happen at much higher temperatures than initially suspected."The bottom line is that if you increase the water vapor concentration, you actually increase the threshold temperature for executing this chemical conversion -- from the stable forms of chlorine to the free radical form," Anderson said. "If the amount of water vapor and the temperature over the U.S. satisfies the conditions for rapid conversion of inorganic chlorine to this free-radical form, we've got a real problem, because the chemistry is identical to what we previously demonstrated is taking place over the Arctic."Also surprising, he added, was the realization that, to throw water vapor high into the atmosphere, storms needn't be unusually large."We have hundreds of measurements world-wide addressing the photochemical structure controlling ozone, but only a limited number of flights over the U.S. in summer," he said. "The flights were studying average storms over the middle-west, and of the 20 observations we made over the U.S., about half demonstrated significant penetration into the stratosphere," he said.The next step in the research, Anderson said, is to conduct a series of tests to confirm whether the free-radical form of chlorine and bromine are present in the stratosphere at significantly elevated levels in the presence of convectively-injected water vapor."In my mind, this is not just a broad public health issue," Anderson said. "This is about actually being able to step out into the sunlight -- it's about your children and your children's health. Of course, we don't know how rapidly the frequency and intensity of these storms will increase, so we can't place a time scale on this problem, but the core issue here is quite straightforward and simple, because we understand this chemistry."

Ozone Holes

July 5, 2012

https://www.sciencedaily.com/releases/2012/07/120705204935.htm

Extreme heat raises climate change questions, concerns

The recent heat wave baking much of the country has prompted many people to ask: Is this due to climate change?

"This is always the million-dollar question, but unfortunately, there's no definitive way to answer it," says Steve Vavrus, a senior scientist in the Nelson Institute Center for Climatic Research at the University of Wisconsin-Madison. "We've experienced extreme heat, drought, floods, wildfires and windstorms throughout history, so in a sense this is nothing unusual. We need time to assess whether this year's set of extreme weather events falls outside of normal variations."The list of unusual conditions over the past year is long. According to the National Oceanic and Atmospheric Administration (NOAA), last winter was the fourth-warmest on record in the United States; spring was the warmest since recordkeeping began in 1895; and April marked the end of the warmest 12-month period in U.S. history.Still, Vavrus says scientists need more information to determine whether global warming is to blame. But he says heat waves like the current one will become more common on a warmer planet as we continue to add greenhouse gases such as carbon dioxide to the atmosphere, primarily through the burning of fossil fuels."I think it's a harbinger of what's to come under greenhouse warming," says Vavrus. "Virtually all climate models simulate more intense and frequent heat waves as the climate warms, and most of the world has experienced increases in extreme heat during the past several decades."That's not good news for air quality or human health. Tracey Holloway, an associate professor of environmental studies, atmospheric and oceanic sciences, and civil and environmental engineering, says hotter temperatures lead to more ground-level ozone. Breathing ozone can damage lungs and worsen bronchitis, emphysema and asthma, and particulate air pollutants can affect a person's lungs and heart."Over the past few weeks, both ozone and particulate matter have increased across much of the country, with the Air Quality Index registering levels deemed 'unhealthy' or 'unhealthy for sensitive groups,'" says Holloway. "In the last week of June, moderate or unhealthy air covered a third to half of the continental U.S."She says overall air quality typically degrades in hot conditions through a variety of physical and chemical processes."Often on the hottest days, we have very stagnant air, so emissions from cars and trucks, power plants and industry, along with natural emissions, have no place to go," she explains. "They hang around near the surface and react in the atmosphere to form ozone and some types of particles."Holloway says heat-related events such as wildfires add harmful pollutants, and the increasing demand for air conditioning drives up power plant emissions.In addition to causing respiratory issues, the excess heat poses direct health risks, according to Jonathan Patz, a professor of environmental studies and population health sciences and director of the UW-Madison Global Health Institute."Of all natural disasters in the U.S., heat waves have caused the most mortality," he says. "This week's heat wave began relatively early in the summer, and early-season heat waves can be particularly deadly, since we are less adapted to the heat, both physiologically and behaviorally."Patz participated in a recent study of hospitalizations during heat waves in Milwaukee over a 16-year period."We found that risks to people with endocrine diseases such as diabetes, and renal disorders like kidney stones, increase during extreme heat waves," says Patz. "So do attempted suicides."He says people in certain urban locations are more affected by the heat."Individuals who live on top-floor apartments, especially those without air conditioning, are at greater risk," he says. "Locations with more black asphalt roofs and roadways can be hotter than areas with more trees and green-space."Patz says the health risks are compounded when extreme heat causes or combines with power outages, such as the extensive loss of electricity following intense wind storms that cut across the Midwest and mid-Atlantic last Friday."Such events are stark reminders of just how vulnerable we remain to extreme weather events," he says.Whether these recent risks and impacts are the result of global climate change remains an unresolved question, according to Jack Williams, director of the Nelson Institute Center for Climatic Research. But he says there's no doubt that the global climate is changing."For the last 40 years of global warming, there is nothing comparable in the instrumental record since about 1880," Williams says. "To find comparable analogs for the amount of warming expected for this century under standard greenhouse gas emission scenarios, you have to go back to the climate changes accompanying the last deglaciation, about 20,000 years ago."

Ozone Holes

June 25, 2012

https://www.sciencedaily.com/releases/2012/06/120625162932.htm

Ozone exposure linked to potential heart attacks

Young, healthy adult volunteers exposed for two hours to ozone developed physiological changes associated with cardiovascular ailments, according to a small study reported in

Study participants showed evidence of vascular inflammation, a potential reduced ability to dissolve artery-blocking blood clots, and changes in the autonomic nervous system that controls the heart's rhythm. The changes were temporary and reversible in these young, healthy participants.Ground level ozone is created when pollutants from vehicles, power plants, industry, chemical solvents and consumer products react in the presence of sunlight. Recent epidemiology studies have reported associations between acute exposure to ozone and death but little is known about the underlying pathophysiological pathways responsible."This study provides a plausible explanation for the link between acute ozone exposure and death," said Robert B. Devlin, Ph.D., the study's lead author and senior scientist at the U.S. Environmental Protection Agency's (EPA) National Health and Environmental Effects Research Laboratory in Research Triangle Park, N.C.Devlin and colleagues focused on a single, short-term exposure and not the effects of years of exposure to ozone.Researchers exposed 23 volunteers, ages 19 to 33, to 0.3 parts per million (ppm) of ozone. The dose was higher than the EPA's eight hour ozone standard of 0.076 ppm. However, a person breathing 0.3 ppm for two hours receives roughly the same amount of ozone as does a person breathing the lower 0.076 ppm for eight hours, Devlin noted.Study participants underwent two controlled exposures -- one to clean air and one to ozone-polluted air -- at least two weeks apart. During each exposure, participants alternated 15-minute periods of stationary cycling and rest.None of the participants reported complaints or physical symptoms after inhaling clean air or ozone. However, immediately following and the morning after ozone inhalation, tests showed significant ozone-induced vascular changes compared to clear-air exposure. These changes included:Epidemiology studies have also associated acute exposure to another ubiquitous air pollutant, particulate matter (PM), with death in elderly people with cardiovascular disease. Particulate matter is tiny airborne particles that can be inhaled into the lungs. Controlled exposure studies of both humans and animals have described PM-induced changes that are very similar to those described in this ozone study, suggesting that both pollutants may be causing death by affecting similar pathways, the researchers said.The World Health Organization estimates 2 million people worldwide, mostly elderly people with cardiovascular disease, die because of acute exposure to air pollution. The EPA puts the yearly U.S. toll at 40,000-50,000 deaths."People can take steps to reduce their ozone exposure, but a lot of physicians don't realize this," Devlin said.The EPA website, Read the American Heart Association scientific statement on air pollution and cardiovascular disease. Take free risk assessment quizzes and find your risk of heart attack, high blood pressure and diabetes.

Ozone Holes

June 12, 2012

https://www.sciencedaily.com/releases/2012/06/120612115920.htm

Volcanic gases could deplete ozone layer

Giant volcanic eruptions in Nicaragua over the past 70,000 years could have injected enough gases into the atmosphere to temporarily thin the ozone layer, according to new research. And, if it happened today, a similar explosive eruption could do the same, releasing more than twice the amount of ozone-depleting halogen gases currently in stratosphere due to humanmade emissions.

Bromine and chlorine are gases that "love to react -- especially with ozone," said Kirstin Krüger, a meteorologist with GEOMAR in Kiel, Germany. "If they reach the upper levels of the atmosphere, they have a high potential of depleting the ozone layer."New research by Krüger and her colleagues, which she presented June 12 at a scientific conference in Selfoss, Iceland, combined a mixture of field work, geochemistry and existing atmospheric models to look at the previous Nicaraguan eruptions. And the scientists found that the eruptions were explosive enough to reach the stratosphere, and spewed out enough bromine and chlorine in those eruptions, to have an effect on the protective ozone layer. Krüger's talk was at the American Geophysical Union's Chapman Conference on Volcanism and the Atmosphere.Steffen Kutterolf, a chemical volcanologist with GEOMAR and one of Krüger's colleagues, tackled the question of how much gas was released during the eruptions. He analyzed gases that were trapped by minerals crystallizing in the magma chambers, and applied a novel method that involves using the high-energy radiation from the German Electron Synchrotron in Hamburg to detect trace elements, including bromine. From that, Kutterolf estimated the amount of gas within magma before the eruptions, as well as the gas content in the lava rocks post-eruption. The difference, combined with existing field data about the size of the eruption, allowed the scientists to calculate how much bromine and chlorine are released.Previous studies have estimated that in large, explosive eruptions -- the type that sends mushroom clouds of ash kilometers high -- up to 25 percent of the halogens ejected can make it to the stratosphere. For this study, the research team used a more conservative estimate of 10 percent reaching the stratosphere, to calculate the potential ozone layer depletion.Taking an average from 14 Nicaraguan eruptions, the scientists found bromine and chlorine concentrations in the stratosphere jumped to levels that are equivalent to 200 percent to 300 percent of the 2011 concentrations of those gases. The Upper Apoyo eruption 24,500 years ago, for example, released 120 megatons of chlorine and 600 kilotons of bromine into the stratosphere.Volcanic sulfate aerosols alone can lead to an ozone increase -- if chlorine levels are at low, pre-industrial levels, Krüger said. But bromine and chlorine are halogens, gases whose atoms have seven electrons in the outer ring. To reach a stable, eight-electron configuration, these atoms will rip electrons off of passing molecules, like ozone. So when an eruption also pumps bromine and chlorine levels into the stratosphere, the ozone-depleting properties of the gases together with aerosols is expected to thin the protective layer."As we have bromine and chlorine together, we believe that this can lead to substantial depletion," she said. "And this is from one single eruption."Because the effects are in the stratosphere, where the volcanic gases can be carried across the globe, eruptions of tropical volcanoes could lead to ozone depletion over a large area, Krüger said, potentially even impacting the ozone over polar regions. However, that's a question for future research to address. Some volcanic gases can last in the stratosphere up to six years, she added, although the most significant impacts from eruptions like Mount Pinatubo were within the first two years.The next step in the research, Krüger said, is to investigate how much damage to the ozone layer the volcanic gases caused in the past -- and what the damage could be from future volcanic eruptions in the active Central American region.The title of the study is "The Combined Bromine and Chlorine Release From Large Explosive Volcanic Eruptions: a Threat to Stratospheric Ozone."

Ozone Holes

June 12, 2012

https://www.sciencedaily.com/releases/2012/06/120612101605.htm

Satellite sees smoke from Siberian fires reach the US coast

Fires burning in Siberia recently sent smoke across the Pacific Ocean and into the U.S. and Canada. Images of data taken by the nation's newest Earth-observing satellite tracked aerosols from the fires taking six days to reach America's shores.

Suomi National Polar-orbiting Partnership (S-NPP) satellite's Ozone Mapping Profiler Suite (OMPS) tracks aerosols, like this smoke, that are transported by winds across the globe.The Voice of Russia reported that 11,000 hectares (about 42.4 square miles) of forests in Siberia were on fire in May and that the Russian Ministry of Emergency Situations says roughly 80 percent of these fires are intentionally set to clear land for farming.Colin Seftor, an atmospheric physicist working for Science Systems and Applications, Inc. at NASA Goddard Space Flight Center, in Greenbelt, Md. studies aerosols using OMPS data and created images from them."This smoke event is one example that shows that what happens over one area of the Earth can easily affect another area thousands of miles away, whether it's from Asia to North America or North America to Europe, and so on. Not only smoke and dust can get carried long distance. Pollutants, and even disease-carrying spores can be carried by the prevailing winds. For this event, I found out that the smoke plumes were lofted up to at least 12 kilometers (or about 7.5 miles) from the intense heat of the fires. At that point the smoke got picked up by higher level winds," Seftor says. Seftor false-colored the images to make the data stand out. He said," The colors on the image are artificial, but what they convey is a sense of the density of the smoke." In the images, he used blue and green colors to represent less smoke. Yellows and pink represent more smoke. Seftor showed smoke density by the level of transparency in the coloration. The less dense the smoke is the more you can see through it, and the more dense it is, the less you can see through it.The thickest area of smoke appears over Mongolia. This high concentration is transported across the Pacific Ocean and crosses into Alaska.Seftor says that unlike photographs, satellite data shows researchers the difference between reflections of smoke and dust from those from snow, ice or the tops of clouds. The UV (ultra-violet) aerosol index is helpful because it makes "seeing" dust and smoke easier even when that background is bright. The aerosol index allows him to separate the aerosol signal from the background."One of the biggest uncertainties we've had in terms of understanding our climate has to do with aerosols and what exactly aerosols do to the climate," Seftor says, adding that the OMPS instrument adds to and expands on decades of scientific research. The Ozone Monitoring Instrument (OMI) was the precursor to OMPS. "Climate changes often occur over long periods, and it takes decades of data and measurements to detect and understand them. "

Ozone Holes

May 16, 2012

https://www.sciencedaily.com/releases/2012/05/120516140004.htm

Humanmade pollutants may be driving Earth's tropical belt expansion: May impact large-scale atmospheric circulation

Black carbon aerosols and tropospheric ozone, both humanmade pollutants emitted predominantly in the Northern Hemisphere's low- to mid-latitudes, are most likely pushing the boundary of the tropics further poleward in that hemisphere, new research by a team of scientists shows.

While stratospheric ozone depletion has already been shown to be the primary driver of the expansion of the tropics in the Southern Hemisphere, the researchers are the first to report that black carbon and tropospheric ozone are the most likely primary drivers of the tropical expansion observed in the Northern Hemisphere.Led by climatologist Robert J. Allen, an assistant professor of Earth sciences at the University of California, Riverside, the research team notes that an unabated tropical belt expansion would impact large-scale atmospheric circulation, especially in the subtropics and mid-latitudes."If the tropics are moving poleward, then the subtropics will become even drier," Allen said. "If a poleward displacement of the mid-latitude storm tracks also occurs, this will shift mid-latitude precipitation poleward, impacting regional agriculture, economy, and society."Study results appear in the May 17 issue of Observations show that the tropics have widened by 0.7 degrees latitude per decade, with warming from greenhouse gases also contributing to the expansion in both hemispheres. To study this expansion, the researchers first compared observational data with simulated data from climate models for 1979-1999. The simulated data were generated by a collection of 20 climate models called the Coupled Model Intercomparison Project version 3 or "CMIP3."The researchers found that CMIP3 underestimates the observed 0.35 degrees latitude per decade expansion of the Northern Hemisphere tropics by about a third. But when they included either black carbon or tropospheric ozone or both in CMIP3, the simulations mimicked observations better, suggesting that the pollutants were playing a role in the Northern Hemisphere tropical expansion.Next, to ensure that their results were not influenced by intrinsic differences between CMIP3's 20 models, the researchers expanded the time period studied to 1970-2009, comparing available observed data with simulated data from NCAR's Community Atmosphere Model (CMIP3 data did not extend to 1970-2009). They then repeated the exercise with the GFDL Atmospheric Model. Using these models allowed the researchers to directly isolate the effects of black carbon and tropospheric ozone on the location of the tropical boundaries.As before, they found that the models underestimate the observed Northern Hemisphere expansion of the tropics by about a third. When black carbon and tropospheric ozone were incorporated in these models, however, the simulations showed better agreement with observations, underscoring the pollutants' role in widening the tropical belt in the Northern Hemisphere."Both black carbon and tropospheric ozone warm the tropics by absorbing solar radiation," Allen explained. "Because they are short-lived pollutants, with lifetimes of one-two weeks, their concentrations remain highest near the sources: the Northern Hemisphere low- to mid-latitudes. It's the heating of the mid-latitudes that pushes the boundaries of the tropics poleward."Allen further explained that with an expansion of the tropics, wind patterns also move poleward, dragging other aspects of atmospheric circulation with them, such as precipitation."For example, the southern portions of the United States may get drier if the storm systems move further north than they were 30 years ago," he said. "Indeed, some climate models have been showing a steady drying of the subtropics, accompanied by an increase in precipitation in higher mid-latitudes. The expansion of the tropical belt that we attribute to black carbon and tropospheric ozone in our work is consistent with the poleward displacement of precipitation seen in these models."Black carbon aerosols are tiny particles of carbon produced from biomass burning and incomplete combustion of fossil fuels. Most of the world's black carbon production occurs in the Northern Hemisphere, with Southeast Asia being a major producer. The same is true of tropospheric ozone, a secondary pollutant that results when volatile organic compounds react with sunlight."Greenhouse gases do contribute to the tropical expansion in the Northern Hemisphere," Allen said. "But our work shows that black carbon and tropospheric ozone are the main drivers here. We need to implement more stringent policies to curtail their emissions, which would not only help mitigate global warming and improve human health, but could also lessen the regional impacts of changes in large-scale atmospheric circulation in the Northern Hemisphere."Thomas Reichler, an associate professor of atmospheric sciences at the University of Utah, noted that the new work by the Allen-led team represents a major advance in climate dynamics research."For a long time it has been unclear to the research community why climate models were unable to replicate the observed changes in the atmospheric wind structure," said Reichler, who was not involved in the study. "This work demonstrates now in very convincing ways that changes in the amount and distribution of tiny absorbing particles in the atmosphere are responsible for the observed changes. Since previous model simulations did not account properly for the effects of these particles on the atmosphere, this work provides a surprisingly simple but effective answer to the original question."Allen, who conceived the research project and designed the study, was joined in the research by Steven C. Sherwood at the University of New South Wales, Australia; Joel Norris at the Scripps Institution of Oceanography, San Diego; and Charles S. Zender at UC Irvine.Next, the research team will study the implications of the tropical expansion from a predominantly hydrological perspective."The question to ask is how far must the tropics expand before we start to implement policies to reduce the emissions of greenhouse gases, tropospheric ozone and black carbon that are driving the tropical expansion?" said Allen, who joined UCR in 2011.

Ozone Holes

May 9, 2012

https://www.sciencedaily.com/releases/2012/05/120509171415.htm

DC3: Chemistry of thunderstorms

NASA researchers are about to fly off on a campaign that will take them into the heart of thunderstorm country.

The Deep Convective Clouds and Chemistry (DC3) field campaign will use an airport in Salina, Kan., as a base to explore the impact of large thunderstorms on the concentration of ozone and other substances in the upper troposphere. The campaign is being led by the National Center for Atmospheric Research in Boulder, Colorado, and is funded by the National Science Foundation (NSF) and NASA."Thunderstorms provide a mechanism for rapid lifting of air from the surface to higher altitudes in a matter of minutes to hours," said James Crawford of NASA's Langley Research Center in Hampton, Va., and a member of the mission's scientific steering committee."This allows molecules that are short-lived and more abundant near the surface to be transported to the upper troposphere in amounts that could not happen under normal atmospheric conditions," he said.Additional chemical impacts come from the production of nitrogen oxides by lightning, but the details of these processes are not well understood."All of this together has an influence on ozone in the coldest part of the atmosphere where it exerts the largest influence on climate," Crawford said. "Of the chemicals we'll be studying, nitrogen oxides in particular are key to the creation of ozone and are produced both naturally by lightning and by human activity through the burning of fossil fuels."The campaign is scheduled to run from May 15 to June 30. NASA partners include Langley, Goddard Space Flight Center in Greenbelt, Md., Marshall Space Flight Center in Huntsville, Ala., Ames Research Center at Moffett Field, Calif. and Dryden Flight Research Center in Edwards, Calif.The troposphere is the lowest part of the atmosphere, extending from the ground up to an average depth of 11 miles in the middle latitudes. It contains about 80 percent of the atmosphere's mass and 99 percent of its water vapor. This region is important because water vapor, ozone, cirrus clouds and particles such as dust contribute to the amount of radiation -- heat -- allowed in and out of the atmosphere, and have a direct impact on the climate system."We tend to associate thunderstorms with heavy rain and lightning, but they also shake things up at the top of cloud level," said NCAR scientist Chris Cantrell, a DC3 principal investigator. "Their impacts high in the atmosphere have effects on climate that last long after the storm dissipates."During the mission, a NASA DC-8 carrying more than 20 instruments measuring scores of substances will make far-reaching flights out of Salina in coordination with a network of ground-based radar, lightning antenna stations and instrumentation in Colorado, Oklahoma and Alabama. The aircraft's home is Dryden Flight Research Center.The DC-8 is flying in tandem with the NSF/NCAR Gulfstream-V, a higher-flying aircraft able to more consistently reach the altitudes where outflow from deep convection deposits material.The DC-8 will sample outflow when possible, but more importantly will focus on lower altitude inflow conditions, and on pre- and post-storm changes in how material is distributed with altitude. Its range will also enable it to sample outflow downwind of storms to examine chemical changes induced by the lifted material.The principal investigators are from NCAR, Pennsylvania State University and Colorado State University, the National Oceanic and Atmospheric Administration, and numerous university and partners and international collaborators. German scientists will bring yet a third plane, a Dassault Falcon.The DC3 mission is related to another airborne campaign examining the role of deep convection in transporting material from the surface to the upper atmosphere. The DC-8 and Gulfstream-V will both participate in the Southeast Asia Composition, Cloud, Climate Coupling Regional Study (SEAC4RS) mission that will take place in August and September this year from a base in Thailand.

Ozone Holes

March 20, 2012

https://www.sciencedaily.com/releases/2012/03/120320163842.htm

Japan shares space station SMILES via atmospheric data distribution

Did you panic when you heard in recent news that two massive solar flares from the Sun were hitting Earth's atmosphere? The coronal mass ejections, or CMEs, typically produced by solar flares might pose a danger, if not for Earth's protective atmosphere and magnetosphere. Using International Space Station research and technology, scientists continue to learn more about the atmosphere, adding important new data to the collective understanding of this important defensive veil.

Atmospheric gasses, held in place by gravity, surround our planet and keep us safe from extreme temperatures, ultraviolet radiation, and the vacuum of space. Meanwhile, the magnetic fields generated by and surrounding Earth -- the magnetosphere -- help to shield us from the ever-present, solar wind-increased radiation events resulting from CMEs.The Japanese Aerospace Exploration Agency, or JAXA, developed a high-precision technology that resides outside the station, mounted on the Japanese Experiment Module-Exposed Facility, or JEM-EF, as part of an investigation to study the chemical makeup of Earth's middle atmosphere. Known as the Superconducting Submillimeter-Wave Limb-Emission Sounder, or SMILES (A cooperation between JAXA and the Japanese National Institute of Information and Communications Technology, or NICT, made the development of SMILES possible. Their combined objective was to use this space station technology to demonstrate highly sensitive submillimeter-wave "the ozone layer."The ozone layer helps to protect life on Earth from harmful ultraviolet radiation, and is destroyed by trace atmospheric constituents such as chlorine and bromine that can be produced from human-made refrigerants, solvents, and other compounds. The data collected by SMILES improves our understanding of how these trace atmospheric constituents impact the ozone layer.A select set of research groups received observation data from SMILES, unique for its high sensitivity detection of atmospheric chemistry. The use of this data can help scientists find answers to questions of climate change, including ozone and global warming research. While SMILES is no longer collecting data, the hardware continues to run as a technology test on orbit.A recent press release from JAXA announced that the confirmed high-precision data from this study, compiled during a 6 month period ending in April 2010, is now available for release to the public. The SMILES data includes 11 types of atmospheric minor elements, such as chlorine compounds and ozone. This knowledge helps to expand scientific understanding of the atmosphere's chemical makeup, specifically in the stratosphere and lower mesosphere.

Ozone Holes

March 1, 2012

https://www.sciencedaily.com/releases/2012/03/120301111111.htm

Sea ice drives arctic air pollutants, NASA finds

Drastic reductions in Arctic sea ice in the last decade may be intensifying the chemical release of bromine into the atmosphere, resulting in ground-level ozone depletion and the deposit of toxic mercury in the Arctic, according to a new NASA-led study.

The connection between changes in the Arctic Ocean's ice cover and bromine chemical processes is determined by the interaction between the salt in sea ice, frigid temperatures and sunlight. When these mix, the salty ice releases bromine into the air and starts a cascade of chemical reactions called a "bromine explosion." These reactions rapidly create more molecules of bromine monoxide in the atmosphere. Bromine then reacts with a gaseous form of mercury, turning it into a pollutant that falls to Earth's surface.Bromine also can remove ozone from the lowest layer of the atmosphere, the troposphere. Despite ozone's beneficial role blocking harmful radiation in the stratosphere, ozone is a pollutant in the ground-level troposphere.A team from the United States, Canada, Germany, and the United Kingdom, led by Son Nghiem of NASA's Jet Propulsion Laboratory in Pasadena, Calif., produced the study, which has been accepted for publication in the Journal of Geophysical Research- Atmospheres. The team combined data from six NASA, European Space Agency and Canadian Space Agency satellites; field observations and a model of how air moves in the atmosphere to link Arctic sea ice changes to bromine explosions over the Beaufort Sea, extending to the Amundsen Gulf in the Canadian Arctic."Shrinking summer sea ice has drawn much attention to exploiting Arctic resources and improving maritime trading routes," Nghiem said. "But the change in sea ice composition also has impacts on the environment. Changing conditions in the Arctic might increase bromine explosions in the future."The study was undertaken to better understand the fundamental nature of bromine explosions, which first were observed in the Canadian Arctic more than two decades ago. The team of scientists wanted to find if the explosions occur in the troposphere or higher in the stratosphere.Nghiem's team used the topography of mountain ranges in Alaska and Canada as a "ruler" to measure the altitude at which the explosions took place. In the spring of 2008, satellites detected increased concentrations of bromine, which were associated with a decrease of gaseous mercury and ozone. After the researchers verified the satellite observations with field measurements, they used an atmospheric model to study how the wind transported the bromine plumes across the Arctic.The model, together with satellite observations, showed the Alaskan Brooks Range and the Canadian Richardson and Mackenzie mountains stopped bromine from moving into Alaska's interior. Since most of these mountains are lower than 6,560 feet (2,000 meters), the researchers determined the bromine explosion was confined to the lower troposphere."If the bromine explosion had been in the stratosphere, 5 miles [8 kilometers] or higher above the ground, the mountains would not have been able to stop it and the bromine would have been transported inland," Nghiem said.After the researchers found that bromine explosions occur in the lowest level of the atmosphere, they could relate their origin to sources on the surface. Their model, tracing air rising from the salty ice, tied the bromine releases to recent changes in Arctic sea ice that have led to a much saltier sea ice surface.In March 2008, the extent of year-round perennial sea ice eclipsed the 50-year record low set in March 2007, shrinking by 386,100 square miles (one million square kilometers) -- an area the size of Texas and Arizona combined. Seasonal ice, which forms over the winter when seawater freezes, now occupies the space of the lost perennial ice. This younger ice is much saltier than its older counterpart because it has not had time to undergo processes that drain its sea salts. It also contains more frost flowers -- clumps of ice crystals up to four times saltier than ocean waters -- providing more salt sources to fuel bromine releases.Nghiem said if sea ice continues to be dominated by younger saltier ice, and Arctic extreme cold spells occur more often, bromine explosions are likely to increase in the future.Nghiem is leading an Arctic field campaign this month that will provide new insights into bromine explosions and their impacts. NASA's Bromine, Ozone, and Mercury Experiment (BROMEX) involves international contributions by more than 20 organizations. The new studies will complement those of a previously conducted NASA field campaign, Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS), which is providing scientists with valuable data for studies of bromine.This study was funded by NASA, the National Oceanic and Atmospheric Administration, the National Science Foundation, the Office of Naval Research, the International Polar Year Program, Environment Canada, the Natural Sciences and Engineering Council of Canada, the European Space Agency, the State of Bremen, the German Aerospace Center, and the European Organisation for the Exploitation of Meteorological Satellites.

Ozone Holes

February 24, 2012

https://www.sciencedaily.com/releases/2012/02/120224110737.htm

CFC substitutes: Good for the ozone layer, bad for climate?

The Montreal Protocol led to a global phase-out of most substances that deplete the ozone layer, such as chlorofluorocarbons (CFCs). A happy side-effect of the gradual ban of these products is that Earth's climate has also benefited because CFCs are also potent greenhouse gases. However, now a "rebound effect" threatens to accelerate the rate of global warming.

Hydrofluorocarbons (HFCs), which have been used in recent years in increasing quantities as substitutes for CFCs, are also climatically very active and many are also extremely long-lived. In the journal It is regarded as the most successful international environmental agreement and has, to date, been ratified by 196 countries -- the Montreal Protocol on Substances That Deplete the Ozone Layer. As a result, CFCs and ozone "killers" will gradually disappear from the atmosphere over the coming decades. And because many of these substances are also very active greenhouse gases, Earth's climate will profit from the sinking concentrations too.So far, so good. In many processes where previously CFCs were used, these are now being increasingly substituted by fluorinated compounds such as HFCs (which, simply put, are similar substances to CFCs but do not contain chlorine and do not deplete stratospheric ozone). They are used as cooling agents in air conditioning plants and refrigerators, as propellants in aerosol cans, as solvents and as foaming agents in the manufacture of foam products. However, there is a downside to the use of HFCs -- they are also very potent greenhouse gases. HFC-134a, also known as R-134a, for example, which is used in automobile air conditioning units, is 1430 more active than the "classic" greenhouse gas carbon dioxide (COThe reduction of greenhouse gas emissions is covered by the Kyoto Protocol. This agreement is, however, not binding for the world's largest emitter of greenhouse gases, the USA (which has never ratified the protocol), nor for threshold and developing countries. In addition the Kyoto Protocol is currently limited to the period from 2000 to 2012. No agreement has yet been reached on extending it. What this means is that the significant increase in global emissions of HFCs seen over the past few years will soon negate the positive effects on climate brought by the Montreal protocol's CFC phase-out.This link is shown by an analysis published in the latest issue of "Science." An international team of researchers, headed by Holland's Guus Velders and including the chemistry Nobel laureate Mario Molina and Empa researcher Stefan Reimann, investigated the unintentional (positive) climate effects resulting from the Montreal Protocol. Since the year 2000 the radiative forcing (a measure of the effect on the climate of chemical substances) of all ozone-depleting substances including CFCs has remained at a more or less constant value of 0.32 W/mVelders, Reimann and their co-authors fear that this positive effect will soon be negated by HFC emissions, which are currently increasing at 10 to 15% annually. In their article they state that "the HFC contribution to climate change can be viewed as an unintended negative side effect" of the Montreal Protocol. At the moment the effect is still small -- about 0.012 W/mAmong other things, the scientists recommend modifying the Montreal protocol so that it also covers the use of long-lived HFCs. Such proposals have already been tabled in previous years by various countries including the USA. "Since it is it is as a result of the Montreal protocol that these substances are being manufactured in increasing amounts, they could be included in the agreement too, so their use can be regulated as well," maintains Reimann. A stepwise phase-out of HFCs is technically feasible since, according to Reimann, chemical and technological alternatives are already available. In the USA for example refrigerators are cooled using HFC-134a; in Switzerland the use of this substance in refrigerators is banned and climate neutral hydrocarbons are used instead.

Ozone Holes

February 14, 2012

https://www.sciencedaily.com/releases/2012/02/120214171040.htm

Short-term exposure to most major air pollutants associated with increased risk of heart attack

Short-term exposure (for up to 7 days) to all major air pollutants, with the exception of ozone, is significantly associated with an increased risk of heart attack, according to a review and meta-analysis of previous studies appearing in the February 15 issue of

The potentially harmful effect of episodes of high air pollution on health has been suspected for more than 50 years. "In industrialized countries, cardiovascular disease is the leading cause of mortality and is associated with significant morbidity. These countries have high pollution levels. Since the 1990s, many epidemiological studies have demonstrated associations between air pollution levels and human health in terms of hospital admissions and overall mortality, including respiratory or cardiovascular mortality. However, the association between air pollution and near-term risk of myocardial infarction [MI; heart attack] remains controversial. Some studies have shown an association, while other studies have found either no association or association only for selected pollutants," according to background information in the article.Hazrije Mustafic, M.D., M.P.H., of the University Paris Descartes, INSERM Unit 970, Paris, and colleagues conducted a systematic review and meta-analysis to examine the association between short-term exposure to air pollutants and the risk of heart attack, and to quantify these associations. The major air pollutants included in the analysis were ozone, carbon monoxide, nitrogen dioxide, sulfur dioxide, and particulate matter (PM) with an aerodynamic diameter of 10 μm (micrometers; PM10) or less and those 2.5 micrometers (PM2.5) or less.The researchers conducted a search of the medical literature and identified 34 studies that met criteria for inclusion in the analysis, which indicated associations of statistical significance between all analyzed air pollutants and heart attack risk, with the exception of ozone. The subgroup analysis, based on study quality, yielded results comparable with those from the overall analysis.The authors suggest a number of possible mechanisms for the associations found. "The first potential mechanism is inflammation. Studies have shown that levels of inflammatory markers such as C-reactive protein are higher as a result of exposure to air pollution. The second potential mechanism is abnormal regulation of the cardiac autonomic system. Several observational studies have linked high levels of air pollution with increased heart rate and decreased heart rate variability. The third possible mechanism is an increase in blood viscosity as a result of air pollution. This association can promote thrombus [blood clot] formation, accelerate the progression of atherosclerosis, and weaken the stability of atherosclerotic plaques."The researchers acknowledge that the magnitude of association found in this study is relatively small compared with those of classic heart attack risk factors, such as smoking, hypertension, or diabetes. "Nevertheless, the population attributable fractions of each pollutant is not negligible because the majority of the population, including young and disabled patients, is exposed to air pollution, particularly in urban settings, and thus an improvement in air quality could have a significant effect on public health.""In conclusion, our meta-analysis is the first to our knowledge to evaluate the quality and magnitude of associations between short-term exposure to major air pollutants and the risk of MI," the authors write. "Further research is needed to determine whether effective interventions that improve air quality are associated with a decreased incidence of MI."

Ozone Holes

February 1, 2012

https://www.sciencedaily.com/releases/2012/02/120201093105.htm

Coastal waters produce halogenated organic molecules that exacerbate stratospheric ozone depletion

Coastal waters of the tropical Western Pacific produce natural halogenated organic molecules involving chlorine, bromine and iodine atoms that may damage the stratospheric ozone layer. This is the conclusion drawn from the initial findings of a field measurement campaign conducted in the South China Sea in the framework of the international SHIVA project. In November and December 2011, the scientists involved in this interdisciplinary project, which is coordinated by physicists from the Institute of Environmental Physics at Heidelberg University, investigated the oceanic sources and atmospheric transport pathways of these trace gases in the waters and air of Malaysia, Brunei and the Philippines.

The halogens chlorine, bromine and iodine are known as ozone-depleting substances. Micro-organisms such as macro-algae and phytoplankton form natural halogenated organic molecules, which are released into the air, where they eventually find their way into the stratosphere. The SHIVA project is testing conjectures based on earlier findings by scientists from Heidelberg University's Institute of Environmental Physics that the ozone layer may not only be harmed by industrial "ozone killers" like chlorofluorocarbons (CFC), but also by these natural halogenated organic molecules. "Our measurements off the coast of Borneo, in the South China Sea and in the Sulu Sea indicate that the biologically productive coastal waters are particularly abundant sources of these trace gases," says overall coordinator Prof. Dr. Klaus Pfeilsticker of Heidelberg University. Involved in the field measurements were the German research ship "Sonne" and various smaller Malaysian vessels. "In addition, our British and Malaysian colleagues did laboratory analyses which indicate that rhodophyta, or red algae, are one of the prime producers of these halogenated organic molecules, due to a stress reaction triggered by oxygen," Prof. Pfeilsticker adds.The German Aerospace Center's (Deutsches Zentrum für Luft- und Raumfahrt, DLR) research plane "Falcon" based in Miri (Borneo) was used to investigate the atmospheric transport pathways of the halogenated organic molecules and their decay products more closely. In the tropics, atmospheric transport of the targeted species to the mid troposphere is fairly rapid due to the shallow atmospheric boundary layer. In addition, in the rainy season convective systems like thunderstorms lift the air masses into the upper troposphere in a matter of hours. "The results from our measurements and models indicate that for the transport of ozone relevant and other trace gases into the upper tropical troposphere, the vertical transport due to intermittent convective systems is the most important factor," says Prof. Pfeilsticker. "From there these gases are transported to the lower stratosphere by radiative heating in the tropical tropopause layer."Next, the scientists will evaluate and interpret the new data with the help of large-scale chemical, transport and global-climate models. "Our aim is to predict the future development of the ozone layer under the influence of anthropogenic climate change in the tropical oceans, atmospheric circulation and photochemistry," says Prof. Pfeilsticker. In the coming years, the transport pathways of the halogenated organic molecules in the tropical tropopause region are to be investigated with high-flying planes like the NASA's"Global Hawk."

Ozone Holes

January 24, 2012

https://www.sciencedaily.com/releases/2012/01/120122152445.htm

New study sheds light on evolutionary origin of oxygen-based cellular respiration

Researchers at the RIKEN SPring-8 Center in Harima, Japan have clarified the crystal structure of quinol dependent nitric oxide reductase (qNOR), a bacterial enzyme that offers clues on the origins of our earliest oxygen-breathing ancestors. In addition to their importance to fundamental science, the findings provide key insights into the production of nitrogen oxide, an ozone-depleting and greenhouse gas hundreds of times more potent than carbon dioxide.

As the central process by which cells capture and store the chemical energy they need to survive, cellular respiration is essential to all life on this planet. While most of us are familiar with one form of respiration, whereby oxygen is used to transform nutrients into molecules of adenosine triphosphate (ATP) for use as energy ("aerobic respiration"), many of the world's organisms breathe in a different way. At the bottom of the ocean and in other places with no oxygen, organisms get their energy instead using substances such as nitrate or sulfur to synthesize ATP, much the way organisms did many billions of years ago ("anaerobic respiration").While less well-known, this latter type of cellular respiration is no less important, fuelling the production of most of the world's nitrous oxide (N2O), an ozone depleting and greenhouse gas 310 times more potent than carbon dioxide. As the enzyme responsible for catalyzing the reactions underlying anaerobic respiration, nitric oxide reductase (NOR) has attracted increasing attention in environmental circles. The mystery of NOR's catalyzing mechanism, however -- which accounts for a staggering 70% of the planet's N2O production -- remains largely unsolved.With their latest research, the team sought an answer to this mystery in the origin of an evolutionary innovation known as the "proton pump." To accelerate ATP-synthesis, aerobic organisms harness the potential of an electrochemical concentration gradient across the cell, created by "pumping" protons out using energy from an oxygen reduction reaction. The enzyme powering this mechanism, cytochrome oxidase (COX), is genetically and structurally similar to NOR, suggesting a common ancestor. No evidence of any "pump," however, has been detected in anaerobic organisms.That is, until now. Using radiation from the RIKEN SPring-8 facility in Harima, Japan, the world's largest synchrotron radiation facility, the researchers probed the 3D structure of qNOR and discovered a channel acting as a proton transfer pathway for a key catalytic reaction. While not itself a proton pump, the position and function of this pathway suggest it is an ancestor of the proton pump found in COX. The finding thus establishes first-ever evidence for a proton pump in anaerobic organisms, shedding light onto the mysterious mechanisms governing the production of nitrogen oxide and the evolutionary path that led to their emergence.

Ozone Holes

January 24, 2012

https://www.sciencedaily.com/releases/2012/01/120119133759.htm

Low temperatures enhance ozone degradation above the Arctic

Extraordinarily cold temperatures in the winter of 2010/2011 caused the most massive destruction of the ozone layer above the Arctic so far: The mechanisms leading to the first ozone hole above the North Pole were studied by scientists of the KIT Institute of Meteorology and Climate Research (IMK). According to these studies, further cooling of the ozone layer may enhance the influence of ozone-destroying substances, e.g. chlorofluorocarbons (CFC), such that repeated occurrence of an ozone hole above the Arctic has to be expected.

About a year ago, IMK scientists, together with colleagues from Oxford, detected that ozone degradation above the Arctic for the first time reached an extent comparable to that of the ozone hole above the South Pole. Then, the KIT researchers studied the mechanisms behind. Their results have now been published in the journal "Geophysical Research Letters."According to IMK studies, occurrence of the Arctic ozone hole was mainly due to the extraordinarily cold temperatures in the ozone layer that is located at about 18 km height in the stratosphere, i.e. the second layer of Earth's atmosphere. There, chlorine compounds originating from chlorofluorocarbons (CFC, e.g. greenhouse gases and refrigerants) and other pollutants are converted chemically at temperatures below -78°C. These chemical conversion products attack the ozone layer and destroy it partly. One of the main statements in the study: If the trend to colder temperatures in the stratosphere observed in the past decades will continue, repeated occurrence of an Arctic ozone hole has to be expected.The team of IMK researchers analyzed measurements of the chemical composition of the atmosphere by the MIPAS satellite instrument developed by KIT. In addition, model calculations were made to determine concrete effects of further cooling of the ozone layer. "We found that further decrease in temperature by just 1°C would be sufficient to cause a nearly complete destruction of the Arctic ozone layer in certain areas," says Dr. Björn-Martin Sinnhuber, main author of the study. Observations over the past thirty years indicate that the stratosphere in cold Arctic winters cooled down by about 1°C per decade on the average. According to Sinnhuber, further development of the ozone layer will consequently be influenced also by climate change. He points out that the increase in carbon dioxide and other greenhouse gases will warm up the bottom air layers near the ground due to the reflection of part of the thermal radiation by the bottom layer of the atmosphere towards Earth's surface, but also result in a cooling of the air layers of the stratosphere above, where the ozone layer is located.After the first discovery of the Antarctic ozone hole in the mid-1980s, CFCs were rapidly identified to be the cause and their use was prohibited by the Montreal Protocol of 1987. However, it will take decades until these substances will have been removed completely from the atmosphere. "Future cooling of the stratosphere would enhance and extend the impacts of these substances on the ozone layer," says Dr. Björn-Martin Sinnhuber. It is now necessary to study potential feedbacks on climate change.The present study is embedded in long-term programs of IMK in this field. In December, the researchers started a new measurement campaign in the Arctic ozone layer in Northern Sweden using a high-altitude aircraft. Again, they encountered extraordinarily low temperatures. However, it is not yet possible to predict whether temperatures will be low enough over a longer term to cause a comparably large degradation of ozone in this winter.

Ozone Holes

December 5, 2011

https://www.sciencedaily.com/releases/2011/12/111205081648.htm

Historic Spanish analysis of atmospheric ozone highlights the importance of chlorofluorocarbon gases

Researchers from the Andalusian Centre for Environmental Studies and the University of Granada have rebuilt the ozone column trends recorded between 1978 and 2008 that rise up over the Iberian Peninsula. The study was published weeks ago in the

The results highlight the influence that the prohibition of aerosols and chlorofluorocarbon gases (CFC) has had. According to Manuel Antón from the Department of Applied Physics of the University of Granada, "although these types of emissions were banned by the 1987 Montreal Protocol, our study reveals that stratospheric ozone did not show signs of recovery until 1995.""We established two measurement periods. For the first, between 1979 and 1994, we saw that stratospheric ozone depletion was significant with higher levels in the north of the peninsula," states Antón. According to the study, the effects of depletion were felt more in cities such as Barcelona, Santander and La Coruña who all saw a reduction in ozone levels of approximately 4% per decade due to dynamic factors in the stratosphere.The second period studied, between 1995 and 2008, differed from the first. For example, ozone levels showed positive trends with greater recovery levels (2.5% per decade) in the north-east of the Peninsula where levels were higher than other regions due to industrial emissions. Antón says that "we have seen that the troposphere ozone contributes in recovering total ozone levels."In contrast to the stratospheric ozone, which acts as a filter against harmful radiation, the tropospheric or ground-level ozone found in the lowest layer of the atmosphere is a secondary pollutant. It mainly comes from the photochemical processes that transform nitrogen oxides and volatile particles from burning fossil fuels into ozone. Heat and light from the sun stimulate such processes which is why ground-level ozone is such a common pollutant in Spain.The results show that in highly industrial areas such as the north-east of Spain, the recovery of the ozone layer was quicker thanks to the ozone contribution of the troposphere to the stratosphere. However, the authors of the study warn that "other anthropogenic effects could complicate the recovery process and result in areas with altered ozone levels."The ozone level measurement data used in the study were taken from two satellites. These were the US satellite TOMS (Total Ozone Mapping Spectrometer, which has provided daily images of the spatial distribution of the ozone between 1978 and 2005) and the European satellite GOME (Global Ozone Monitoring Experiment which more recently took measurements from July 1995 to June 2011). The University of Évora (Portugal), the Institute of Atmospheric Sciences and Climate in Bologna (Italy) and the German Aerospace Centre also participated in the study.

Ozone Holes

December 2, 2011

https://www.sciencedaily.com/releases/2011/12/111201163608.htm

Sharp decline in pollution from U.S. coal power plants, NASA satellite confirms

A team of scientists have used the Ozone Monitoring Instrument (OMI) on NASA's Aura satellite to confirm major reductions in the levels of a key air pollutant generated by coal power plants in the eastern United States. The pollutant, sulfur dioxide, contributes to the formation of acid rain and can cause serious health problems.

The scientists, led by an Environment Canada researcher, have shown that sulfur dioxide levels in the vicinity of major coal power plants have fallen by nearly half since 2005. The new findings, the first satellite observations of this type, confirm ground-based measurements of declining sulfur dioxide levels and demonstrate that scientists can potentially measure levels of harmful emissions throughout the world, even in places where ground monitoring is not extensive or does not exist. About two-thirds of sulfur dioxide pollution in American air comes from coal power plants. The scientists attribute the decline in sulfur dioxide to the Clean Air Interstate Rule, a rule passed by the U.S. Environmental Protection Agency in 2005 that called for deep cuts in sulfur dioxide emissions. In response to that rule, many power plants in the United States have installed desulfurization devices and taken other steps that limit the release of sulfur dioxide. The rule put a cap on emissions, but left it up to power companies to determine how to reduce emissions and allowed companies to trade pollution credits.While scientists have used the Ozone Monitoring Instrument to observe sulfur dioxide levels within large plumes of volcanic ash and over heavily polluted parts of China in the past, this is the first time they have observed such subtle details over the United States, a region of the world that in comparison to fast-growing parts of Asia now has relatively modest sulfur dioxide emissions. Just a few decades ago, sulfur dioxide pollution was quite severe in the United States. Levels of the pollutant have dropped by about 75 percent since the 1980s due largely to the passage of the Clean Air Act.Vitali Fioletov, a scientist based in Toronto at Environment Canada, and his colleagues developed a new mathematical approach that made the improved measurements a reality. The approach centers on averaging measurements within a 30 miles radius (50 km) of a sulfur dioxide source over several years. "Vitali has developed an extremely powerful technique that makes it possible to detect emissions even when levels of sulfur dioxide are about four times lower than what we could detect previously," said Nickolay Krotkov, a researcher based at NASA's Goddard Space Flight Center in Greenbelt, Md., and a coauthor of the new paper.The technique allowed Fioletov and his colleagues to pinpoint the sulfur dioxide signals from the 40 largest sulfur dioxide sources in the United States -- generally coal power plants that emit more than 70 kilotons of sulfur dioxide per year. The scientists observed major declines in sulfur dioxide emissions from power plants in Alabama, Georgia, Indiana, Kentucky, North Carolina, Ohio, Pennsylvania and West Virginia by comparing levels of the pollutant for an average of the period 2005 to 2007 with another average from 2008 to 2010."What we're seeing in these satellite observations represents a major environmental accomplishment," said Bryan Bloomer, an Environmental Protection Agency scientist familiar with the new satellite observations. "This is a huge success story for the EPA and the Clean Air Interstate Rule," he said.The researchers focused their analysis on the United States to take advantage of the presence of a robust network of ground-based instruments that monitor sulfur dioxide emissions inside power plant smokestacks. The ground-based instruments have logged a 46 percent decline in sulfur dioxide levels since 2005 -- a finding consistent with the 40 percent reduction observed by OMI."Now that we've confirmed that the technique works, the next step is to use it for other parts of the world that don't have ground-based sensors," said Krotkov. "The real beauty of using satellites is that we can apply the same technique to the entire globe in a consistent way." In addition, the team plans to use a similar technique to monitor other important pollutants that coal power plants release, such as nitrogen dioxide, a precursor to ozone.OMI, a Dutch and Finnish built instrument, was launched in 2004, as one of four instruments on the NASA Aura satellite, and can measure sulfur dioxide more accurately than any satellite instrument flown to date. Though OMI remains in very good condition and scientists expect it to continue producing high-quality data for many years, the researchers also hope to use data from an upcoming Dutch-built OMI follow-on instrument called TROPOMI that is expected to launch on a European Space Agency satellite in 2014.On July 6, 2011, the U.S. Environmental Protection Agency (EPA) finalized the Cross-State Air Pollution Rule (CSAPR), requiring 27 states to significantly reduce power plant emissions that contribute to ozone and fine particle pollution in other states. This rule replaces EPA's 2005 Clean Air Interstate Rule (CAIR). A December 2008 court decision kept the requirements of CAIR in place temporarily but directed EPA to issue a new rule to implement Clean Air Act requirements concerning the transport of air pollution across state boundaries. This action responds to the court's concerns.

Ozone Holes

November 21, 2011

https://www.sciencedaily.com/releases/2011/11/111117154635.htm

Ozone from rock fracture could serve as earthquake early warning

Researchers the world over are seeking reliable ways to predict earthquakes, focusing on identifying seismic precursors that, if detected early enough, could serve as early warnings.

New research, published this week in the journal Scientists in the lab of Raúl A. Baragiola, a professor of engineering physics in the University of Virginia School of Engineering and Applied Science set up experiments to measure ozone produced by crushing or drilling into different igneous and metamorphic rocks, including granite, basalt, gneiss, rhyolite and quartz. Different rocks produced different amounts of ozone, with rhyolite producing the strongest ozone emission.Some time prior to an earthquake, pressures begin to build in underground faults. These pressures fracture rocks, and presumably, would produce detectable ozone.To distinguish whether the ozone was coming from the rocks or from reactions in the atmosphere, the researchers conducted experiments in pure oxygen, nitrogen, helium and carbon dioxide. They found that ozone was produced by fracturing rocks only in conditions containing oxygen atoms, such as air, carbon dioxide and pure oxygen molecules, indicating that it came from reactions in the gas. This suggests that rock fractures may be detectable by measuring ozone.Baragiola began the study by wondering if animals, which seem -- at least anecdotally -- to be capable of anticipating earthquakes, may be sensitive to changing levels of ozone, and therefore able to react in advance to an earthquake. It occurred to him that if fracturing rocks create ozone, then ozone detectors might be used as warning devices in the same way that animal behavioral changes might be indicators of seismic activity.He said the research has several implications."If future research shows a positive correlation between ground-level ozone near geological faults and earthquakes, an array of interconnected ozone detectors could monitor anomalous patterns when rock fracture induces the release of ozone from underground and surface cracks," he said."Such an array, located away from areas with high levels of ground ozone, could be useful for giving early warning to earthquakes."He added that detection of an increase of ground ozone might also be useful in anticipating disasters in tunnel excavation, landslides and underground mines.Baragiola's co-authors are U.Va. research scientist Catherine Dukes and visiting student Dawn Hedges.

Ozone Holes

November 10, 2011

https://www.sciencedaily.com/releases/2011/11/111109143007.htm

Greenhouse gas index continues to climb

NOAA's updated Annual Greenhouse Gas Index (AGGI), which measures the direct climate influence of many greenhouse gases such as carbon dioxide and methane, shows a continued steady upward trend that began with the Industrial Revolution of the 1880s.

Started in 2004, the AGGI reached 1.29 in 2010. That means the combined heating effect of long-lived greenhouse gases added to the atmosphere by human activities has increased by 29 percent since 1990, the "index" year used as a baseline for comparison. This is slightly higher than the 2009 AGGI, which was 1.27, when the combined heating effect of those additional greenhouse gases was 27 percent higher than in 1990."The increasing amounts of long-lived greenhouse gases in our atmosphere indicate that climate change is an issue society will be dealing with for a long time," said Jim Butler, director of the Global Monitoring Division of NOAA's Earth System Research Laboratory in Boulder, Colo. "Climate warming has the potential to affect most aspects of society, including water supplies, agriculture, ecosystems and economies. NOAA will continue to monitor these gases into the future to further understand the impacts on our planet."The AGGI is analogous to the dial on an electric blanket -- that dial does not tell you exactly how hot you will get, nor does the AGGI predict a specific temperature. Yet just as turning the dial up increases the heat of an electric blanket, a rise in the AGGI means greater greenhouse warming.NOAA scientists created the AGGI recognizing that carbon dioxide is not the only greenhouse gas affecting the balance of heat in the atmosphere. Many other long-lived gases also contribute to warming, although not currently as much as carbon dioxide.The AGGI includes methane and nitrous oxide, for example, greenhouse gases that are emitted by human activities and also have natural sources and sinks. It also includes several chemicals known to deplete Earth's protective ozone layer, which are also active as greenhouse gases. The 2010 AGGI reflects several changes in the concentration of these gases, including:Scientists at NOAA's Earth System Research Laboratory prepare the AGGI each year from atmospheric data collected through an international cooperative air sampling network of more than 100 sites around the world.NOAA researchers developed the AGGI in 2004 and have so far back calculated it to 1978. Atmospheric composition data from ice core and other records could allow the record to be extended back centuries.The Annual Greenhouse Gas Index (AGGI) is available online at:

Ozone Holes

October 21, 2011

https://www.sciencedaily.com/releases/2011/10/111020145106.htm

Significant ozone hole remains over Antarctica

The Antarctic ozone hole, which yawns wide every Southern Hemisphere spring, reached its annual peak on September 12, stretching 10.05 million square miles, the ninth largest on record. Above the South Pole, the ozone hole reached its deepest point of the season on October 9 when total ozone readings dropped to 102 Dobson units, tied for the 10th lowest in the 26-year record.

The ozone layer helps protect the planet's surface from harmful ultraviolet radiation. NOAA and NASA use balloon-borne instruments, ground instruments, and satellites to monitor the annual South Pole ozone hole, global levels of ozone in the stratosphere, and the humanmade chemicals that contribute to ozone depletion."The upper part of the atmosphere over the South Pole was colder than average this season and that cold air is one of the key ingredients for ozone destruction," said James Butler, director of NOAA's Global Monitoring Division in Boulder, Colo. Other key ingredients are ozone-depleting chemicals that remain in the atmosphere and ice crystals on which ozone-depleting chemical reactions take place."Even though it was relatively large, the size of this year's ozone hole was within the range we'd expect given the levels of manmade, ozone-depleting chemicals that continue to persist," said Paul Newman, chief atmospheric scientist at NASA's Goddard Space Flight Center.Levels of most ozone-depleting chemicals are slowly declining due to international action, but many have long lifetimes, remaining in the atmosphere for decades. Scientists around the world are looking for evidence that the ozone layer is beginning to heal, but this year's data from Antarctica do not hint at a turnaround.In August and September (spring in Antarctica), the sun begins rising again after several months of darkness. Circumpolar winds keep cold air trapped above the continent, and sunlight-sparked reactions involving ice clouds and humanmade chemicals begin eating away at the ozone. Most years, the conditions for ozone depletion ease by early December, and the seasonal hole closes.Levels of most ozone-depleting chemicals in the atmosphere have been gradually declining since an international treaty to protect the ozone layer, the 1987 Montreal Protocol, was signed. That international treaty caused the phase out of ozone-depleting chemicals, then used widely in refrigeration, as solvents and in aerosol spray cans.Global atmospheric models predict that stratospheric ozone could recover by the middle of this century, but the ozone hole in the Antarctic will likely persist one to two decades beyond that, according to the latest analysis by the World Meteorological Organization, the Researchers do not expect a smooth, steady recovery of Antarctic ozone, because of natural ups and downs in temperatures and other factors that affect depletion, noted NOAA ESRL scientist Bryan Johnson. Johnson helped co-author a recent NOAA paper that concluded it could take another decade to begin discerning changes in the rates of ozone depletion.Johnson is part of the NOAA team tracks ozone depletion around the globe and at the South Pole with measurements made from the ground, in the atmosphere itself and by satellite. Johnson's "ozonesonde" group has been using balloons to loft instruments 18 miles into the atmosphere for 26 years to collect detailed profiles of ozone levels from the surface up. The team also measures ozone with satellite and ground-based instruments.This November marks the 50th anniversary of the start of total ozone column measurements by the NOAA Dobson spectrophotometer instrument at South Pole station. Ground-based ozone column measurements started nearly two decades before the yearly Antarctic ozone hole began forming, therefore helping researchers to recognize this unusual change of the ozone layer.NASA measures ozone in the stratosphere with the Ozone Monitoring Instrument (OMI) aboard the Aura satellite. OMI continues a NASA legacy of monitoring the ozone layer from space that dates back to 1972 and the launch of the Nimbus-4 satellite.

Ozone Holes

October 18, 2011

https://www.sciencedaily.com/releases/2011/10/111013153955.htm

Future forests may soak up more carbon dioxide than previously believed

North American forests appear to have a greater capacity to soak up heat-trapping carbon dioxide gas than researchers had previously anticipated.

As a result, they could help slow the pace of human-caused climate warming more than most scientists had thought, a U-M ecologist and his colleagues have concluded.The results of a 12-year study at an experimental forest in northeastern Wisconsin challenge several long-held assumptions about how future forests will respond to the rising levels of atmospheric carbon dioxide blamed for human-caused climate change, said University of Michigan microbial ecologist Donald Zak, lead author of a paper published online this week in "Some of the initial assumptions about ecosystem response are not correct and will have to be revised," said Zak, a professor at the U-M School of Natural Resources and Environment and the Department of Ecology and Evolutionary Biology in the College of Literature, Science, and the Arts.To simulate atmospheric conditions expected in the latter half of this century, Zak and his colleagues continuously pumped extra carbon dioxide into the canopies of trembling aspen, paper birch and sugar maple trees at a 38-acre experimental forest in Rhinelander, Wis., from 1997 to 2008.Some of the trees were also bathed in elevated levels of ground-level ozone, the primary constituent in smog, to simulate the increasingly polluted air of the future. Both parts of the federally funded experiment -- the carbon dioxide and the ozone treatments -- produced unexpected results.In addition to trapping heat, carbon dioxide is known to have a fertilizing effect on trees and other plants, making them grow faster than they normally would. Climate researchers and ecosystem modelers assume that in coming decades, carbon dioxide's fertilizing effect will temporarily boost the growth rate of northern temperate forests.Previous studies have concluded that this growth spurt would be short-lived, grinding to a halt when the trees can no longer extract the essential nutrient nitrogen from the soil.But in the Rhinelander study, the trees bathed in elevated carbon dioxide continued to grow at an accelerated rate throughout the 12-year experiment. In the final three years of the study, the COIt appears that the extra carbon dioxide allowed trees to grow more small roots and "forage" more successfully for nitrogen in the soil, Zak said. At the same time, the rate at which microorganisms released nitrogen back to the soil, as fallen leaves and branches decayed, increased."The greater growth has been sustained by an acceleration, rather than a slowing down, of soil nitrogen cycling," Zak said. "Under elevated carbon dioxide, the trees did a better job of getting nitrogen out of the soil, and there was more of it for plants to use."Zak stressed that growth-enhancing effects of COThe ozone portion of the 12-year experiment also held surprises.Ground-level ozone is known to damage plant tissues and interfere with photosynthesis. Conventional wisdom has held that in the future, increasing levels of ozone would constrain the degree to which rising levels of carbon dioxide would promote tree growth, canceling out some of a forest's ability to buffer projected climate warming.In the first few years of the Rhinelander experiment, that's exactly what was observed. Trees exposed to elevated levels of ozone did not grow as fast as other trees. But by the end of study, ozone had no effect at all on forest productivity."What happened is that ozone-tolerant species and genotypes in our experiment more or less took up the slack left behind by those who were negatively affected, and that's called compensatory growth," Zak said. The same thing happened with growth under elevated carbon dioxide, under which some genotypes and species fared better than others."The interesting take home point with this is that aspects of biological diversity -- like genetic diversity and plant species compositions -- are important components of an ecosystem's response to climate change," he said. "Biodiversity matters, in this regard."Co-authors of the Ecology Letters paper were Kurt Pregitzer of the University of Idaho, Mark Kubiske of the U.S. Forest Service and Andrew Burton of Michigan Technological University. The work was funded by grants from the U.S. Department of Energy and the U.S. Forest Service.

Ozone Holes

October 3, 2011

https://www.sciencedaily.com/releases/2011/10/111003190937.htm

Unprecedented Arctic ozone loss last winter

A NASA-led study has documented an unprecedented depletion of Earth's protective ozone layer above the Arctic last winter and spring caused by an unusually prolonged period of extremely low temperatures in the stratosphere.

The study, published online Oct. 2 in the journal The Antarctic ozone hole forms when extremely cold conditions, common in the winter Antarctic stratosphere, trigger reactions that convert atmospheric chlorine from human-produced chemicals into forms that destroy ozone. The same ozone-loss processes occur each winter in the Arctic. However, the generally warmer stratospheric conditions there limit the area affected and the time frame during which the chemical reactions occur, resulting in far less ozone loss in most years in the Arctic than in the Antarctic.To investigate the 2011 Arctic ozone loss, scientists from 19 institutions in nine countries (United States, Germany, The Netherlands, Canada, Russia, Finland, Denmark, Japan and Spain) analyzed a comprehensive set of measurements. These included daily global observations of trace gases and clouds from NASA's Aura and CALIPSO spacecraft; ozone measured by instrumented balloons; meteorological data and atmospheric models. The scientists found that at some altitudes, the cold period in the Arctic lasted more than 30 days longer in 2011 than in any previously studied Arctic winter, leading to the unprecedented ozone loss. Further studies are needed to determine what factors caused the cold period to last so long."Day-to-day temperatures in the 2010-11 Arctic winter did not reach lower values than in previous cold Arctic winters," said lead author Gloria Manney of NASA's Jet Propulsion Laboratory in Pasadena, Calif., and the New Mexico Institute of Mining and Technology in Socorro. "The difference from previous winters is that temperatures were low enough to produce ozone-destroying forms of chlorine for a much longer time. This implies that if winter Arctic stratospheric temperatures drop just slightly in the future, for example as a result of climate change, then severe Arctic ozone loss may occur more frequently."The 2011 Arctic ozone loss occurred over an area considerably smaller than that of the Antarctic ozone holes. This is because the Arctic polar vortex, a persistent large-scale cyclone within which the ozone loss takes place, was about 40 percent smaller than a typical Antarctic vortex. While smaller and shorter-lived than its Antarctic counterpart, the Arctic polar vortex is more mobile, often moving over densely populated northern regions. Decreases in overhead ozone lead to increases in surface ultraviolet radiation, which are known to have adverse effects on humans and other life forms.Although the total amount of Arctic ozone measured was much more than twice that typically seen in an Antarctic spring, the amount destroyed was comparable to that in some previous Antarctic ozone holes. This is because ozone levels at the beginning of Arctic winter are typically much greater than those at the beginning of Antarctic winter.Manney said that without the 1989 Montreal Protocol, an international treaty limiting production of ozone-depleting substances, chlorine levels already would be so high that an Arctic ozone hole would form every spring. The long atmospheric lifetimes of ozone-depleting chemicals already in the atmosphere mean that Antarctic ozone holes, and the possibility of future severe Arctic ozone loss, will continue for decades."Our ability to quantify polar ozone loss and associated processes will be reduced in the future when NASA's Aura and CALIPSO spacecraft, whose trace gas and cloud measurements were central to this study, reach the end of their operational lifetimes," Manney said. "It is imperative that this capability be maintained if we are to reliably predict future ozone loss in a changing climate."Other institutions participating in the study included Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany; NASA Langley Research Center, Hampton, Va.; Royal Netherlands Meteorological Institute, De Bilt, The Netherlands; Delft University of Technology, 2600 GA Delft, The Netherlands; Science Systems and Applications, Inc., Greenbelt, Md., and Hampton, Va.; Science and Technology Corporation, Lanham, Md.; Environment Canada, Toronto, Ontario, Canada; Central Aerological Observatory, Russia; NOAA Earth System Research Laboratory, Boulder, Colo.; Arctic Research Center, Finnish Meteorological Institute, Finland; Danish Climate Center, Danish Meteorological Institute, Denmark; Eindhoven University of Technology, Eindhoven, The Netherlands; Arctic and Antarctic Research Institute, St. Petersburg, Russia; National Institute for Environmental Studies, Japan; National Institute for Aerospace Technology, Spain; and University of Toronto, Ontario, Canada.For more information on NASA's Aura mission, visit:

Ozone Holes

September 27, 2011

https://www.sciencedaily.com/releases/2011/09/110927073159.htm

Climate change set to increase ozone-related deaths over next 60 years, scientists warn

Scientists are warning that death rates linked to climate change will increase in several European countries over the next 60 yrs.

A new study, which is being presented at the European Respiratory Society's Annual Congress in Amsterdam, predicts that Belgium, France, Spain and Portugal will see the biggest climate-induced increase in ozone-related deaths over the next 60 years.The research is part of the Climate-TRAP project and its health impact assessment lead by Prof Bertil Forsberg from the Umea University in Sweden. The aim is to prepare the health sector for changing public health needs due to climate change.According to the World Health Organization (WHO), climate change that has occurred since the 1970s caused over 140,000 excess deaths annually by the year 2004. In addition to its impact on clean air, drinking water and crop production, many deadly diseases such as malaria and those which cause diarrhea are particularly sensitive to climate change.In this new research, the scientists used emission scenarios and models to assess the health impacts of a changing climate. They took projections from two greenhouse gas emission scenarios, A2 and A1B, and two global climate models, ECHAM4 and HADLEY, to simulate how the various future ozone levels are affected by climate change.They compared four periods: baseline period (1961-1990); the current situation (1990-2009); nearer future (2012-2050); and further future (2041-2060).The findings revealed that since 1961, Belgium, Ireland, The Netherlands and the UK have seen the biggest impact on ozone-related deaths due to climate change. The results predicted that the biggest increase over the next 50 yrs is likely to be seen in Belgium, France, Spain and Portugal, who could expect an increase of between 10 and 14%. However, Nordic and Baltic countries are predicted to see a decrease over the same period.Dr Hans Orru, air pollution expert from the Umea University and University of Tartu in Estonia, explains: "Ozone is a highly oxidative pollutant, linked with hospitalisations and deaths due to problems with the respiratory system. Ground-level ozone formation is due to rise as temperatures increase with climate change. The results of our study have shown the potential effects that climate change can have on ozone levels and how this change will impact upon the health of Europeans."Professor Marc Decramer, President of the ERS, said: "Outdoor air pollution is the biggest environmental threat in Europe. If we do not act to reduce levels of ozone and other pollutants, we will see increased hospital admissions, extra medication and millions of lost working days. As part of the European Respiratory Roadmap, which was launched last month, the ERS is calling for a collaborative approach between health professionals and policy makers, to protect vulnerable populations from the damaging effects air pollutants can have."

Ozone Holes

September 27, 2011

https://www.sciencedaily.com/releases/2011/09/110926081921.htm

Plant 'body clock' observed in tropical rainforest; Research to aid ozone pollution predictions

Predictions of the ground-level pollutant ozone may be more accurate in the future, thanks to new research into plant circadian rhythms.

The research was led by Lancaster University and is published in the journal Ozone is formed in the atmosphere when volatile organic compounds like isoprene -- which is emitted by some plants -- react with nitrogen oxides from car engines or industry. Ozone at ground level is very harmful to human health, may decrease crop yields, and is a greenhouse gas.Researchers, led by Professor Nick Hewitt of the Lancaster Environment Centre, have found that the rate at which plants emit isoprene is influenced by their body clock or circadian rhythm.This 24-hour circadian rhythm, which also controls leaf movement and respiration in plants, has never before been observed operating in concert in a stand of trees. The discovery alters current estimates of plant-derived isoprene emissions. Ground-level ozone concentrations, calculated using the new isoprene emissions, are then closer to observed concentrations, going some way to resolve a long-standing deficiency in computer simulation of ground-level ozone.Professor Hewitt said: "We spend billions of pounds trying to control ozone -- for example, by putting catalytic convertors in new cars in order to prevent emissions of oxides of nitrogen. This discovery of the circadian rhythm operating on the forest canopy scale is another step in better understanding ozone and improving our models of the atmosphere."The researchers examined measurements of isoprene made above tropical rainforest and oil palm plantations in Sabah in Malaysia, carried out as part of a £2.5m UK/Malaysian scientific research project.Dr Eiko Nemitz of the UK Centre for Ecology and Hydrology said: "Our flux measurements show that emissions of isoprene are under circadian control, strongly in the oil palm plantation and less strongly in the rainforest. These ecosystems therefore emit less isoprene than current emissions models predict."Professor Rob MacKenzie of the University of Birmingham, who led the initial ozone modelling studies, added "Using various models of atmospheric chemistry, we show that this more complete understanding of the processes controlling isoprene emissions yields a better predictive capability for ground-level ozone, especially in isoprene-sensitive regions of the world."These regions include the south eastern US, the Mediterranean, the Middle East, parts of South East Asia and Japan.Using computer simulations from the National Centre for Atmospheric Research in Colorado, the team then compared their simulated ground-level ozone with real-life ozone measurements at 290 atmospheric monitoring sites in the US. They found that their model accuracy significantly improved when it included circadian control of isoprene emissions.The work was funded by the Natural Environment Research Council and the paper is published as part of the Royal Society's South East Asian Rainforest Research Programme.

Ozone Holes

August 30, 2011

https://www.sciencedaily.com/releases/2011/08/110830111350.htm

Future climate change may increase asthma attacks in children

Mount Sinai School of Medicine researchers have found that climate change may lead to more asthma-related health problems in children, and more emergency room (ER) visits in the next decade.

The data, published in the current issue of the The research team, led by Perry Sheffield, MD, Assistant Professor of Preventive Medicine at Mount Sinai School of Medicine, used regional and atmospheric chemistry models to reach its calculations. They linked regional climate and air quality information to New York State Department of Health records of pediatric, asthma-related emergency room visits in 14 counties that are part of the New York City metropolitan area. Then they simulated ozone levels for June through August for five consecutive years in the 2020s, and compared them with 1990s levels. The researchers found a median increase of 7.3 percent in ozone-related asthma emergency department visits, with increases ranging from 5.2 percent to 10.2 percent per county."Our study shows that these assessment models are an effective way of evaluating the long-term impact of global climate change on a local level," said Dr. Sheffield. "This study is a jumping off point to evaluate other outcomes including cost utilization, doctors' visits, missed school days, and a general understanding of the overall burden of climate change on children with asthma."Dr. Sheffield and her team plan to continue using these models to understand the specific impacts of climate change. The authors conclude that better measures to reduce carbon pollution that contributes to global climate change as well as pollution that forms ozone need to be implemented.Funding for this study was provided by the National Institutes of Health Research Training Program in Environmental Pediatrics.

Ozone Holes

August 30, 2011

https://www.sciencedaily.com/releases/2011/08/110829210818.htm

Mysteries of ozone depletion continue 25 years after the discovery of the Antarctic ozone hole

Even after many decades of studying ozone and its loss from our atmosphere miles above Earth, plenty of mysteries and surprises remain, including an unexpected loss of ozone over the Arctic this past winter, an authority on the topic said in Denver Colorado on May 29. She also discussed chemistry and climate change, including some proposed ideas to "geoengineer" Earth's climate to slow down or reverse global warming.

The talk happened at the 242nd National Meeting & Exposition of the American Chemical Society (ACS), being held this week.In a Kavli Foundation Innovations in Chemistry Lecture, Susan Solomon, Ph.D., of the University of Colorado, Boulder, said that the combined efforts of scientists, the public, industry and policy makers to stop ozone depletion is one of science's greatest success stories, but unanswered questions remain. And ozone is still disappearing."We're no longer producing the primary chemicals -- chlorofluorocarbons (CFCs) -- that caused the problem, but CFCs have very long lifetimes in our atmosphere, and so we'll have ozone depletion for several more decades," said Solomon. "There are still some remarkable mysteries regarding exactly how these chlorine compounds behave in Antarctica -- and it's amazing that we still have much to learn, even after studying ozone for so long."The ozone layer is crucial to life on Earth, forming a protective shield high in the atmosphere that blocks potentially harmful ultraviolet rays in sunlight. Scientists have known since 1930 that ozone forms and decomposes through chemical processes. The first hints that human activity threatened the ozone layer emerged in the 1970s, and included one warning from Paul Crutzen, Ph.D., that agricultural fertilizers might reduce ozone levels. Another hint was from F. Sherwood Rowland, Ph.D., and Mario Molina, Ph.D., who described how CFCs in aerosol spray cans and other products could destroy the ozone layer. The three shared a 1995 Nobel Prize in Chemistry for that research. In 1985, British scientists discovered a "hole," a completely unexpected area of intense ozone depletion over Antarctica. Solomon's 1986 expedition to Antarctica provided some of the clinching evidence that underpinned a global ban on CFCs and certain other ozone-depleting gases.Evidence suggests that the ozone depletion has stopped getting worse. "Ozone can be thought of as a patient in remission, but it's too early to declare recovery," said Solomon. And surprises, such as last winter's loss of 40% of the ozone over the Arctic still occur due to the extremely long lifetimes of ozone-destroying substances released years ago before the ban.Solomon also took listeners on a tour of gases and aerosols that affect climate change and described how these substances can contribute to global warming."On the thousand-year timescale, carbon dioxide is by far the most important greenhouse gas produced by humans, but there are some other interesting -- though much less abundant -- gases such as perfluorinated compounds that also last thousands of years and similarly affect our climate for millennia," said Solomon.Increases in atmospheric "greenhouse gases" such as carbon dioxide trap heat in the atmosphere, causing Earth's temperature to creep upward. Global warming is causing ocean levels to rise and could lead some regions to become dry "dust bowls."Dealing with global warming has prompted a lot of interesting research on how to reduce greenhouse gas emissions, how to adapt to a changing climate and on the possibility of 'geoengineering' to cool the climate."Recent studies on 'geoengineering' the Earth's climate involve stratospheric particles of different sorts," she said. "Most of these schemes involve sulfate particles, but other types have been proposed."The talk took place on Monday, August 29 in the Wells Fargo Theater at the Colorado Convention Center.Sponsored by The Kavli Foundation, a philanthropic organization that supports basic scientific research, the lectures are designed to address the urgent need for vigorous, "outside the box" thinking by scientists as they tackle the world's mounting challenges, including climate change, emerging diseases, and water and energy shortages."We are dedicated to advancing science for the benefit of humanity, promoting public understanding of scientific research, and supporting scientists and their work," said Kavli Foundation President Robert W. Conn in a statement. "The Kavli Foundation Innovations in Chemistry Lecture program at the ACS national meetings fits perfectly with our commitment to support groundbreaking discovery and promote public understanding."The Kavli lectures debuted at the Anaheim meeting in March during this International Year of Chemistry and will continue through 2013. They will address the urgent need for vigorous, new, "outside-the-box"- thinking, as scientists tackle many of the world's mounting challenges like climate change, emerging diseases, and water and energy shortages. The Kavli Foundation, an internationally recognized philanthropic organization known for its support of basic scientific innovation, agreed to sponsor the lectures in conjunction with ACS in 2010.

Ozone Holes

August 30, 2011

https://www.sciencedaily.com/releases/2011/08/110829153413.htm

Monitoring ground-level ozone from space

Satellite views of the Midwestern United States show that ozone levels above 50 parts per billion (ppb) along the ground could reduce soybean yields by at least 10 percent, costing more than $1 billion in lost crop production, according to U.S. Department of Agriculture (USDA) scientists.

In a 5-year study led by the National Aeronautics and Space Administration, Agricultural Research Service (ARS) molecular biologist Lisa Ainsworth, ARS plant physiologist Fitz Booker, and university scientists surveyed widespread ozone damage to soybeans in Iowa, Illinois and Indiana, using both ozone surface monitors and satellite instruments.Ainsworth works at the ARS Global Change and Photosynthesis Research Unit in Urbana, Ill., and Booker works at the ARS Plant Science Research Unit in Raleigh, N.C. ARS is USDA's principal intramural scientific research agency.Satellite information is useful for investigating ozone impacts on crop yields because satellite information is available for rural regions, where ground monitoring networks do not exist. Satellite observations, which are also available for farmland in countries without ground networks, could provide important insight into the global extent of ozone reduction of crop yields.Ozone levels in most urban areas of the United States have declined with improvements in emission controls, but they are still high enough to damage soybean, peanut, cotton, rice, tomato and other crops. Ozone levels are expected to rise in countries like India and China as growing populations are able to afford more cars and build more power plants. Another concern is that ozone levels will rise in developing countries, whose people can least withstand losses of staples such as rice and wheat.Ainsworth's and Booker's findings are consistent with those from their SoyFACE (Soybean Free Air Concentration Enrichment) experiments and studies in outdoor open-top chambers. SoyFACE involves testing plants in open-air field conditions under atmospheric conditions predicted for the year 2050. The consistency of the satellite data with SoyFACE findings and the agreement with data from ozone surface monitors suggests that satellites provide an effective way to monitor crop damage from ozone.This research, in support of the USDA priority of responding to climate change, was published in the journal

Ozone Holes

August 23, 2011

https://www.sciencedaily.com/releases/2011/08/110822135018.htm

Southern South American wildfires expected to increase

A new University of Colorado Boulder study indicates a major climate oscillation in the Southern Hemisphere that is expected to intensify in the coming decades will likely cause increased wildfire activity in the southern half of South America.

The research team used tree rings dating to 1506 to track past wildfire activity in the forests of Patagonia tied to the Southern Annular Mode, or SAM, a climate oscillation that creates low atmospheric pressure in the Antarctic that is tied to warmer and drier conditions in southern South America. The tree rings showed that when SAM was in its positive phase, there were widespread fires in both dry woodlands and rainforests in Patagonia, a region that straddles Argentina and Chile, said CU-Boulder Research Associate Andres Holz, lead study author."Our study shows for about the past 250 years, the Southern Annular Mode has been the main driver in creating droughts and fires in two very different ecosystems in southern South America," said Holz. "Climate models suggest an increase in SAM beginning in the 1960s due to greenhouse gas increases and Antarctic ozone depletion probably will cause this region to be drought-prone and fire-prone for at least the next 100 years."A paper on the subject by Holz and CU-Boulder geography Professor Thomas Veblen was published in Holz and Veblen compared past wildfire records for two ecologically distinct regions in Patagonia -- the relatively dry region of southern Patagonia in Argentina and the temperate rainforest of Patagonia in northern Chile. While the tree ring historical record showed increased fires in both regions correlated with a positive SAM, the trend has been less pronounced in northern Patagonia in the past 50 years, likely because of fire-suppression efforts there, Holz said.But the decades of fire suppression have caused the northern Patagonian woodlands to become denser and more prone towildfire during hot and dry years, Holz said."Even in areas of northern Patagonia where fire suppression previously had been effective, record surface areas of woodlands and forests have burned in recent years of extreme drought," said Veblen. "And since this is in an area of rapid residential growth into wildland-urban interface areas, this climate-driven trend towards increasing fire risk is becoming a major problem for land managers and homeowners."The two CU-Boulder researchers studied reconstructions of tree rings going back more than 500 years from 432 trees at 42 sample sites in northern Argentina and southern Chile -- the largest available data set of annual, readable tree ring records in the Southern Hemisphere. The tree rings, which indicate climate cycles and reveal the scars of old fires, showed that wildfires generally increased in both regions when SAM was in its strong, positive phase.Although the Antarctic ozone hole stopped growing in about 2000 as a result of a ban on ozone-depleting gases and now appears to be slowly repairing itself, a 2011 paper by researchers at the National Center for Atmospheric Research in Boulder indicates ozone recovery and greenhouse gas influences essentially will cancel each other out, preventing SAM from returning to its pre-1960s levels."Before the Industrial Revolution, SAM intensified naturally at times to create drought situations in Patagonia," Holz said. "But in the last 80 years or so, the natural variation has been overwhelmed by a bias toward a positive SAM phase because of ozone-depleting chemicals and greenhouse gases we have put in the atmosphere."The research effort was supported by the National Geographic Society, the National Science Foundation, the CU Beverly Sears Small Grants Program and the Council on Research and CreativeResearch of the CU Graduate School."As warming and drying trends continue, it is likely that wildfire activity will increase even in woodland areas where fire suppression has previously been effective," Holz and Veblen wrote in

Ozone Holes

August 22, 2011

https://www.sciencedaily.com/releases/2011/08/110822111755.htm

Breeding ozone-tolerant crops

U.S. Department of Agriculture (USDA) scientists working with the University of Illinois at Urbana-Champaign found that future levels of ground-level ozone could reduce soybean yields by an average 23 percent.

Randy Nelson, geneticist and research leader with the USDA Agricultural Research Service Soybean/Maize Germplasm, Pathology, and Genetics Research Unit in Urbana, Ill., and Lisa Ainsworth, a molecular biologist with the ARS Global Change and Photosynthesis Research Unit in Urbana, are screening soybean varieties for ozone tolerance and sensitivity in SoyFACE (Soybean Free Air Concentration Enrichment) experiments. They are working with Amy Betzelberger, a graduate research assistant in the Department of Plant Biology at the University of Illinois, and other University of Illinois colleagues.ARS is USDA's principal intramural scientific research agency.SoyFACE involves testing plants in open-air field conditions under atmospheric conditions predicted for the year 2050. At that time, ozone concentrations are expected to be 50 percent higher than today's concentrations.During 2007 and 2008, Nelson, Ainsworth, Betzelberger and their colleagues tested 10 Midwestern soybean varieties that had been released between 1952 and 2003. The varieties were selected from initial tests of 22 cultivars and experimental lines evaluated for four years.The researchers found that exposure to 82 parts per billion (ppb) ozone reduced soybean yields by an average 23 percent across all 10 varieties. They also found significant differences in ozone tolerance among the varieties. This shows the potential for breeding more ozone-tolerant varieties.Since ozone concentrations have been rising for decades, the scientists initially thought that varieties developed more recently would be more ozone-tolerant. But the scientists didn't see any significant improvement in ozone tolerance in soybean varieties released since the 1980s.

Ozone Holes

August 19, 2011

https://www.sciencedaily.com/releases/2011/08/110815113538.htm

Climate change and ozone destruction hastened with nitrous oxide used in agriculture

Researchers have discovered a new binding site for nitrous oxide (N

Nitrous oxide (NNThe functionality and mechanisms of this important enzyme had not been thoroughly researched until Dr Anja Pomowski successfully clarified the structure of a NThe newly discovered structure shows first that the ratio and amount of substances in the metal centre of the enzyme have only been described incompletely thus far, and that they contain an additional sulphur atom. Second, the team also identified the binding of the N

Ozone Holes

July 31, 2011

https://www.sciencedaily.com/releases/2011/07/110729175415.htm

Soybean genetic treasure trove found in Swedish village

The first screening by U.S. Department of Agriculture (USDA) scientists of the American ancestors of soybeans for tolerance to ozone and other stresses had an eye-opening result: The world superstars of stress resistance hailed from a little village in far northern Sweden, called Fiskeby.

The screeners, geneticist Tommy Carter and plant physiologist Kent Burkey, are with the Agricultural Research Service (ARS) in Raleigh, NC. Carter works in the ARS Soybean and Nitrogen Fixation Research Unit, and Burkey is in the agency's Plant Science Research Unit. ARS is USDA's principal intramural scientific research agency.After analyzing thousands of soybean types to generate the family tree of North American soybeans, Carter found 30 ancestors, which together account for 92 percent of the genetic material in North American soybeans. He screened these ancestors first for salt tolerance. Two lines of vegetable soybeans, Fiskeby 840-7-3 and Fiskeby III, were the most salt tolerant.Carter screened for aluminum tolerance, and again the Fiskeby plants stood out -- and the same thing happened when he screened for tolerance to drought and high ozone levels. The Fiskeby plants also were found to be resistant to iron deficiency and toxic soil aluminum.The scientists searched breeder pedigree records and found that only a few U.S. cultivars trace their ancestry to the Fiskeby stress-tolerant types. This indicates that there is great potential to increase tolerance to ozone and other stresses in North American soybeans by adding genes from Fiskeby.Burkey, Carter and Jim Orf, a geneticist at the University of Minnesota at St. Paul, have crossed Fiskeby III with ozone-susceptible Mandarin Ottawa soybeans and developed 240 breeding lines from the offspring.With the help of funding from the United Soybean Board of Chesterfield, Mo., the team is mapping the genes in these lines to see which are connected to resistance to ozone and the other stresses.The Swedish soybeans appear to have an even more pronounced resistance to ozone than to the other stresses. Understanding the ozone effect may be key to unraveling the secrets of the broad stress resistance of the Swedish soybeans.

Ozone Holes

July 16, 2011

https://www.sciencedaily.com/releases/2011/07/110715162908.htm

NASA's Aura satellite measures pollution 'Butterfly' from fires in Central Africa

Fires raging in central Africa are generating a high amount of pollution that is showing up in data from NASA's Aura Satellite, with the ominous shape of a dark red butterfly in the skies over southern part of the Democratic Republic of the Congo and northern Angola.

An image of the pollution from agricultural fires in central Africa was created from data of nitrogen dioxide (NOEach year, people in the region burn croplands to clear fields after harvests. Burning is also used to create new growth in pastures and move grazing animals to new locations.NODetection of NOOMI measures NOOMI data is archived at the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC), and is provided by KNMI, the Koninklijk Nederlands Meteorologisch Instituut (Royal Netherlands Meteorological Institute). Dr. P.F. Levelt is the Principal Investigator of OMI, Dr. J. Tamminen is the Finnish Co-PI, and Dr. P.K. Bhartia leads the U.S. OMI science team. Dr. James Gleason (NASA) and Pepijn Veefkind (KNMI) are PIs of the OMI NO

Ozone Holes

July 1, 2011

https://www.sciencedaily.com/releases/2011/07/110701164042.htm

NASA's Aura Satellite measures pollution from New Mexico, Arizona fires

NASA's Aura Satellite has provided a view of nitrogen dioxide levels coming from the fires in New Mexico and Arizona. Detecting nitrogen dioxide is important because it reacts with sunlight to create low-level ozone or smog and poor air quality.

The fierce Las Conchas fire threatened the town and National Laboratory in Los Alamos, while smoke from Arizona's immense Wallow Fire and the Donaldson Fire in central New Mexico also created nitrogen dioxides (NOAn image showing nitrogen dioxide levels from June 27 to 29, 2011 was created from OMI data using the NASA Giovanni system by Dr. James Acker at NASA's Goddard Space Flight Center in Greenbelt, Md. The highest levels of NOLow-level ozone (smog) is hazardous to the health of both plants and animals, and ozone in association with particulate matter causes respiratory problems in humans.On July 1, Inciweb reported that the Las Conchas fire is currently burning on 93,678 acres and was three percent contained. An infrared flyover at 4 a.m. MDT on July 1 reported 103,842 acres burned. InciWeb is the "Incident Information System" website that reports wildfire conditions throughout the country.The Donaldson fire is estimated to cover 72,650 acres and is located to the southeast of the Las Conchas fire. Inciweb reported on July 1 that the fire is burning in the Lincoln National Forest and Mescalero-Apache Tribal lands and is not accessible. The terrain is steep and rocky. It is located about 10 miles northwest of Ruidoso Downs, N.M.Inciweb reported on July 1 that "smoke from the fire is impacting the communities of Ruidoso, Ruidoso Downs, Capitan, Lincoln, Hondo, Fort Stanton, Picacho, Tinnie, San Patricio, Glencoe and other surrounding areas." In east central Arizona, the Wallow Fire is now 95 percent contained, according to InciWeb. Total acres burned are 538,049, including 15,407 acres in New Mexico.Emissions from coal-burning power plants located in northwest New Mexico were also visible in the image.OMI data is archived at the NASA Goddard Earth Sciences Data and Information Services Center (GES DISC), and is provided by KNMI, the Koninklijk Nederlands Meteorologisch Instituut (Royal Netherlands Meteorological Institute). Dr. P.F. Levelt is the Principal Investigator of OMI, Dr. J. Tamminen is the Finnish Co-PI, and Dr. P.K. Bhartia leads the U.S. OMI science team. Dr. James Gleason (NASA) and Pepijn Veefkind (KNMI) are PIs of the OMI NOFor more information about the Aura Satellite's OMI instrument, visit: For more information about NO

Ozone Holes

June 30, 2011

https://www.sciencedaily.com/releases/2011/06/110630111528.htm

Climate change increases the risk of ozone damage to plants, Swedish research finds

Ground-level ozone is an air pollutant that harms humans and plants. Both climate and weather play a major role in ozone damage to plants. Researchers at the University of Gothenburg, Sweden, have now shown that climate change has the potential to significantly increase the risk of ozone damage to plants in northern and central Europe by the end of this century.

"The increased risk of ozone damage to vegetation is mainly due to rising ozone concentrations and higher temperatures in the future," says Jenny Klingberg at the University of Gothenburg's Department of Plant and Environmental Sciences. "The most important effect on agricultural crops is premature aging, which result in smaller harvests with lower quality."Ozone is an atmospheric gas that is found at a height of 10-40 kilometres above Earth's surface. Here the ozone layer protects against the sun's ultraviolet rays and is vital for life on Earth. Ozone is also formed at ground level when car exhaust fumes react in the presence of sunlight. This ground-level ozone is an air pollutant that is toxic to humans. Plants are more sensitive than humans and ground-level ozone generates large costs in the form of reduced crop yields in agriculture and reduced forest growth.Researchers have traditionally estimated the risk of ozone damage to plants based on the concentration of ozone in the ambient air. The negative effects of ozone on vegetation are more closely related to the uptake of ozone through the stomatal openings on the plant leaves. The study carried out by Klingberg is one of the first to use this method to estimate the risk of ozone damage to vegetation in the climate of the future."The results show that the risk of ozone damage to plants is greatest in central Europe where ozone concentrations are high and climatic conditions promote uptake of ozone through the stomata. Weather and climate affect both the concentration of ground-level ozone in the ambient air and to what degree the stomata are open."However, the risk of ozone damage is also affected by the carbon dioxide concentration in the air. Research indicates that the plants' stomata are less open when the concentration of carbon dioxide increases."The models show that higher carbon dioxide concentrations in the air could mean that the risk of ozone damage to crops and deciduous trees will not increase," says Klingberg. "But the magnitude of this effect is uncertain, especially for trees. If the effect of carbon dioxide on the stomata will turn out to be small, future climate change has the potential to significantly increase the risk of ozone damage to vegetation in northern and central Europe."The calculations in the study were performed for two future climate change scenarios.

Ozone Holes

May 16, 2011

https://www.sciencedaily.com/releases/2011/05/110516102253.htm

Research aircraft Polar 5 returned from spring measurements in the high Arctic

The research aircraft Polar 5 of the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association returned to Bremerhaven from a six-week expedition in the high Arctic on May 6. Joint flights with aircraft of the European and American space agencies (ESA and NASA) were a novelty in sea ice research. Simultaneous measurements with a large number of sensors on three planes underneath the CryoSat-2 satellite led to unique data records. Furthermore, the international team composed of 25 scientists and engineers collected data on trace gases, aerosols and meteorological parameters that will be evaluated at the research institutes involved in the coming months.

The route of the Polar 5 of the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association took it from Barrow (Alaska) via Inuvik, Resolute Bay, Eureka, Alert (all in northern Canada) and Station Nord (Greenland) all the way to Longyearbyen on Spitsbergen. These sites were the base stations for the measurement flights to the uninhabited Arctic areas. The total flight time, including measurements and travel time, came to 130 hours. Temperatures below minus 30°C in some cases were a challenge for both team and material.One of the key aspects of the expedition were large-scale sea ice thickness measurements in the inner Arctic, in which researchers of the Alfred Wegener Institute and the University of Alberta cooperated closely. For this purpose they used a four metre long electromagnetic ice thickness sensor, called EM Bird. The Polar 5 towed the sensor on an 80 metre long rope at a height of 15 metres above the ice surface for the surveys. A preliminary evaluation of the measurement results shows that one-year-old sea ice in the Beaufort Sea (north of Canada/Alaska) is about 20-30 centimetres thinner this year than in the two previous years. In 2009 the ice thickness was 1.7 metres on average, in 2010 1.6 metres and in 2011 around 1.4 metres. "I expect that this thin one-year-old sea ice will not survive the melting period in summer," Dr. Stefan Hendricks assesses the situation. In several weeks his colleagues from the sea ice group at the Alfred Wegener Institute will present their model calculations for the sea ice minimum in 2011, which will also include the data now collected.Joint flights with other polar research aircraft below the orbit of the ESA (European Space Agency) CryoSat-2 satellite marked the highlight of the sea ice thickness measurements. This satellite has been surveying the Arctic sea ice from an altitude of 700 kilometres since summer 2010. The coordinated measurement flights with ESA and NASA aircraft served the purpose of examining the accuracy of CryoSat-2 ice thickness measurements in spring.Arctic aerosols, which play a role in the formation of clouds, among other things, were another key aspect. Aerosol distribution and the carbon content of the particles in the Arctic were mapped by means of several vertical and horizontal profiles at a low altitude of 60 metres and at a normal flight altitude of 3000 metres. The aircraft measurements were coordinated with the overflights of the CALIPSO satellite, which records global aerosol and cloud distribution data from space. Moreover, meteorological soundings in the central Arctic as well as measurements of trace gases, such as ozone, were carried out. They confirmed the measurements of 2009 that showed very low ozone concentrations over large sections of the Arctic Ocean covered by sea ice. By combining all trace gas measurements in connection with meteorological measurements, it will be possible to better understand the processes of ozone depletion in the air layers up to an altitude of approx. 15 kilometres (troposphere).

Ozone Holes