Abstract
We investigated how climate change could affect ambient ozone concentrationsand the subsequent human health impacts. Hourly concentrations were estimated for 50eastern US cities for five representative summers each in the 1990s and 2050s, reflectingcurrent and projected future climates, respectively. Estimates of future concentrations were based on the IPCC A2 scenario using global climate, regional climate, and regional air quality models. This work does not explore the effects of future changes in anthropogenicemissions, but isolates the impact of altered climate on ozone and health. The cities’ ozonelevels are estimated to increase under predicted future climatic conditions, with the largest increases in cities with present-day high pollution. On average across the 50 cities, thesummertime daily 1-h maximum increased 4.8 ppb, with the largest increase at 9.6 ppb. Theaverage number of days/summer exceeding the 8-h regulatory standard increased 68%.Elevated ozone levels correspond to approximately a 0.11% to 0.27% increase in daily totalmortality. While actual future ozone concentrations depend on climate and other influencessuch as changes in emissions of anthropogenic precursors, the results presented here indicate that with other factors constant, climate change could detrimentally affect air quality and thereby harm human health.

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