Sensitivity of Ozone Exceedences to Increasing Maximum Temperatures in the U.S

The photochemical production of tropospheric ozone is influenced by concentrations of two classes of precursor gases, nitrogen oxides and volatile organic compounds. The reaction rates are also governed by air temperature within the atmospheric boundary layer. This study examines the statistical relationship between surface air temperature and days exceeding the EPA's National Ambient Air Quality Standard for ozone at selected locations in the United States. A probabilistic model for computing the annual exceedences of ozone concentrations is applied using climate change estimates of maximum daily temperatures for the years 2030 and 2050. The results indicate regional variation in potentially increased human health risk to ozone pollution. These results do not take into account future changes in pollutant emissions, which are highly dependent on economic and policy decisions.