Seasonal simulation of tropospheric ozone over the Eastern U.S.: An application of a coupled regional climate and air quality modeling system

The socioeconomic impacts of air pollution could increase due to climate change. To assess possible changes, model simulations of pollutant concentrations need to be performed at climatic (seasonal) timescales rather than at episodic (days) timescales used to assess abatement strategies under current climate conditions. Such a modeling system was developed and consists of a regional climate model (RCM), an emissions model, and an air quality model (AQM). As a pilot study, this system was used to simulate ozone concentrations for an anomalously warm period (June-August 1995). Based on analyses for several key cities, good agreement with observations generally was found for the diurnal cycle and for several multi-day periods of high and low ozone concentrations. Better comparisons between observations and the monthly average quantities were found, and this may be a more suitable comparison for air quality simulation in future climate.