Analyses of PEM-2 (Pollution Episodic Model Version 2) Model Evaluation Results for Short-Term Urban Particulate Matter

摘要

The Pollution Episodic Model Version 2 (PEM-2), an urban dispersion model, has been evaluated with measurements from the 1982 Philadelphia Aerosol Field Study data base in order to investigate its ability to model 12-hour average concentrations of particulate matter less than 10 micrometers (PM sub 10). Regional PM sub 10 background was derived from the measured concentration at an upwind site selected as the background monitor with the modeled PM sub 10 concentrations subtracted because all sites were in the emissions region. About 70% of the measured PM sub 10 at most monitoring sites was contributed by regional background. Model performance was determined from statistical measures of difference and correlation between observed and modeled concentrations paired in time and location. Statistical results were better for modeled plus background values versus observed concentrations. Mean and high-five PM sub 10 concentrations from the PEM-2 model were about 25% lower than RAM predictions at four sites within the city limits, and 35-40% lower at the two most distant sites from the urban center.