Effect of rising Asian emissions on surface ozone in the United States

The effect of increasing fossil fuel combustion in eastern Asia on surface O-3 air pollution in the United States is examined with a global three-dime nsional tropospheric chemistry model. Tripling of Asian anthropogenic emiss ions from 1985 to 2010 is expected to increase monthly mean O-3 concentrati ons by 2-6 ppbv in the western United States and by 1-3 ppbv in the eastern United States, the maximum effect being in April-June. This increase would more than offset the benefits of 25% domestic reductions in anthropogenic emissions of NOx and hydrocarbons in the western United States. Asian influ ence may be less under the stagnant conditions leading to violations of the U.S. air quality standard. Nevertheless, our results suggest that a global perspective is necessary when designing a strategy to meet regional O-3 ai r quality objectives.