The application and evaluation of a simulation of a high O3 and PM2.5 episode during August 2002 over the eastern United States

The chemical and physical processes conducive to high O3 and particulate episodes have been well documented in recent years. Here we present the results from a modeling study during the summer of 2002 over the eastern United States, with particular emphasis on the August 8-15 high pollution period. The modeling system consists of the Penn State/NCAR MM5 mesoscale meteorological model, EPA Models-3/CMAQ air quality model, and the SMOKE emissions processing system, with a grid resolution of 12 km. There are numerous surface-based networks that monitor trace gases (O3, CO, SO2, NO2, NOy) and PM2.5 mass and species (SO4, NO3, EC, OC) to allow for a detailed evaluation of model performance on an hourly and daily basis. In addition, we examine the model predictions of several trace gas species in the vertical to about 3 km. An examination of the major PM2.5 species composition will be used as a diagnostic tool for model performance. Such an assessment is a critical component in the development of regulatory policies aimed at the mitigation of O3, PM2.5, and regional haze over the region.