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.
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
