United States Environmental Protection Agency &EPA OR9 US EPA Office of Research and Development National Exposure Research Laboratory Ozone Research Ozone Ozone is a naturally occurring chemical in the atmosphere. However, ozone concentrations can be increased many fold in the lower atmosphere (troposphere) by emissions of atmospheric contaminants such as Volatile Organic Compounds (VOCs) and Nitrogen Oxides (NOx). Increases in tropospheric ozone concentrations are widespread, and elevated tropospheric ozone can make vegetation and humans vulnerable to injury. NERL scientists play key roles in state-of-the science research into assessing ozone concentrations and behavior, and in demonstrating the relevance of the science to policy and regulatory requirements. The North American Research Strategy for Tropospheric Ozone The North American Research Strategy for Tropospheric Ozone (NARSTO) is a collaborative public and private effort to define and implement research to further understand the science of tropospheric ozone. NARSTO's first major project was to initiate an assessment for tropospheric ozone. This assessment described the current state of ozone science as well as highlighted the relevance of ozone science to policy makers in the United States, Canada, and Mexico. Taking into account the lessons learned from the assessment, a revised research strategy is being drafted for ozone. NERL Scientists and managers played significant roles in the initiation and production of the NARSTO assessment. The Role of Nitrogen Oxides and Volatile Organic Compounds in Ozone Formation According to a 1991 National Research Council report, the previous United States emissions control efforts may have focused too heavily on control of VOCs for reducing ozone pollution. The Southern Oxidants Study, funded by EPA, explored the scientific issues concerning the roles that both VOCs and NOx play in contributing to ozone levels. This research used observation-based models to investigate the relative effectiveness of VOC and NOx controls for reducing ozone in urban and rural areas in the southeast. Based on the study's data, control of VOCs would be more effective than controlling NOx for reducing ozone in urban areas. In rural areas the opposite of this trend was seen. The findings in the Southern Oxidants Study are significant because they provide invaluable guidance about the most effective emission control efforts. Good Moderate Unhealthy For Very Unhealthy Sensitive Groups Unhealthy Hazardous Color Codes for Ozone Action Days ------- Ozone Research Benefits Findings from the Southern Oxidants Study provides significant regulatory guidance about the most effective emission control efforts. Results of the Southern Oxidants Study report are directly relevant to the improvement of instrumentation for national monitoring networks associated with the National Ambient Air Quality Standards. • NARSTO ozone assessment includes many significant findings, including: ozone concentrations are decreasing or remaining constant in most areas in North America, and decreases in ozone is likely associated with decreases in mobile source emissions. Purpose • NERL's participation in ozone research and assessment supports EPA's efforts to improve the management community's ability to evaluate and assess impacts of ozone management practices, particularly in controlling VOC and NOx emissions in ozone formation. The NARSTO assessment described ozone science and highlighted its relevance to policymakers across North America. • NERL's ozone research aids in the implementation of sound regulatory decision-making. Accomplishments A series of NARSTO Critical Review papers were commissioned that span the horizon of ozone science, including trends assessment, monitoring/measurement methods, atmospheric modeling, and source emissions. A NARSTO Assessment Document was written that relates the current knowledge of ozone to the needs of air quality managers in North America. Observation-Based Modeling methods were used to determine the relative effectiveness of VOC and NOx controls for reducing ozone in urban and rural areas in the southeastern United States. Participants Southern Oxidants Study: U.S. Environmental Protection Agency, Georgia Institute of Technology, North Carolina State University, University of Alabama at Huntsville, University Corporation for Atmospheric Research National Center for Atmospheric Research, Brookhaven National Laboratory, and the Tennessee Valley Authority. Tropospheric Ozone Assessment: U.S. Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory; other participants include federal/state/provincial/local governments, industry groups, universities consultants, and others. NARSTO Southern Oxidants Study For More Information*. Kenneth Schere Dr. Paul Solomon schere.kenneth@epa.gov solomon.paul@epa.gov WEB ANNOUNCEMENT MARCH 2001 ------- |