This paper provides a synthesis of results that have emerged from recent modeling studies of the potential sensitivity of U.S. regional ozone (O3) concentrations to global climate change (ca. 2050). This research has been carried out under the auspices of an ongoing U.S. Environmental Protection Agency (EPA) assessment effort to increase scientific understanding of the multiple complex interactions among climate, emissions, atmospheric chemistry, and air quality. The ultimate goal is to enhance the ability of air quality managers to consider global change in their decisions through improved characterization of the potential effects of global change on air quality, including O3 The results discussed here are interim, representing the first phase of the EPA assessment. The aim in this first phase was to consider the effects of climate change alone on air quality, without accompanying changes in anthropogenic emissions of precursor pollutants. Across all of the modeling experiments carried out by the different groups, simulated global climate change causes increases of a few to several parts per billion (ppb) in summertime mean maximum daily 8-h average O3 concentrations over substantial regions of the country. The different modeling experiments in general do not, however, simulate the same regional patterns of change. These differences seem to result largely from variations in the simulated patterns of changes in key meteorological drivers, such as temperature and surface insolation. How isoprene nitrate chemistry is represented in the different modeling systems is an additional critical factor in the simulated O3 response to climate change.

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Footnotes

U.S. Environmental Protection Agency, Washington, D.C.

University of Illinois at Urbana-Champaign, Urbana, Illinois

Carnegie Mellon University, Pittsburgh, Pennsylvania

Northeast States for Coordinated Air Use Management, Boston, Massachusetts

California Air Resources Board, Sacramento, California

National Research Council Canada, Ottawa, Ontario, Canada

University of California, Berkeley, Berkeley, California

National Center for Atmospheric Research, Boulder, Colorado

Pacific Northwest National Laboratory, Richland, Washington

University at Albany, Albany, New York

Science Applications International Corporation, San Diego, California

Harvard University, Cambridge, Massachusetts

Columbia University, New York, New York

Washington State University, Pullman, Washington

U.S. Forest Service Pacific Northwest Research Station, Portland, Oregon

Georgia Institute of Technology, Atlanta, Georgia

Weather It Is, Ltd., Efrat, Israel

University of Washington, Seattle, Washington

U.S. Department of Agriculture Natural Resources Conservation Service, Portland, Oregon

University of Patras, Rio Patras, Greece

Foundation for Research and Technology—Hellas, Heraklion, Crete, Greece

National Aeronautics and Space Administration/Goddard Institute for Space Studies, New York, New York

Konkuk University, Seoul, South Korea

ADDITIONAL AFFILIATIONS: KUNKEL— Desert Research Institute, Reno, Nevada; LIN—Harvard University, Cambridge, Massachusetts