Particulate matter modeling in the Los Angeles basin using SAQM-AERO

The SARMAP air quality model, enhanced with aerosol modeling capability, an d its associated components were developed to understand causes of ozone (O -3) and particulate matter exceedances in the San Joaquin Valley of Califor nia. In order for this modeling system to gain increasing acceptance and us e in guiding air quality management, it is important to assess how transpor table this modeling system is across geographic domains. We describe the fi rst application of the modeling system outside the "home" domain for which it was developed and evaluated. We have chosen the August 27-28, 1987, inte nsive monitoring period of the Southern California Air Quality Study to eva luate the performance of the modeling system and to assess its sensitivity to emission control options. The predicted surface concentrations of O-3 an d other gas-phase species were spatially and temporally correlated with mea sured data. The fractional normalized absolute error was 0.32 to 0.36 for O -3, and somewhat larger for other species. The fractional normalized bias f or O-3 on August 27 and 28, 1987, was 0.02 to 0.04. The simulated PM2.5 mas s and constituent species concentrations reproduced the magnitude and varia bility of the observed daytime concentrations at most locations; however, n ighttime PM2.5 concentrations were overpredicted by the model. The model's response to emission control options was consistent with other models of th e same genre.