This study compares several transportation-related air quality models. Two line-source models were used: Caline4 (California Department of Transportation) and Hiway2 (US Environmental Protection Agency). Two mobile-source models, Mobile5b (US Environmental Protection Agency) and COPERT3 (European Environment Agency), along with real-world emission factors were used and evaluated as well. Model predictions of NOx concentrations were compared to measured values at two sites in Israel, differing by fleet composition and physical layout ('at-grade' and a 'cut/depressed' road sections). The process indicated that emission factors generated by COPERT3 are the most appropriate for free flowing traffic situations in Israel. Predictions by both line-source models were similar when applied to 'at-grade' road sections. When applied to 'cut/depressed' sections, Hiway2 better predicted concentrations during unstable conditions, while Caline4 better predicted concentrations during stable conditions and peak concentrations. (Author/publisher).
Abstract