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Support Center for Regulatory Atmospheric Modeling (SCRAM)

Dispersion Modeling Applications

Provides access to modeling applications involving dispersion models, including model comparisons and source culpability studies.

Urban Area Assessment of Direct PM2.5   As part of the Regulatory Impact Assessment for the proposed PM2.5 National Ambient Air Quality Standards (NAAQS) (Appendix B), we applied the AERMOD modeling system to three urban areas to provide concentration estimates of directly emitted PM2.5 by species across a specified network of receptors within each urban area. This assessment quantifies the impacts of local sources of primary PM2.5 within Birmingham, Seattle, and Detroit by predicting the spatial variability of direct PM2.5 concentrations within each urban area and quantifying the impact of specific emissions source groups to ambient PM2.5 concentrations at Federal Reference Method (FRM) monitoring sites.

Each of these areas has different characteristics in terms of the mixture of emissions sources, meteorology, and associated PM2.5 air quality issues. As such, they are representative of other areas across the eastern and western US and therefore this assessment provides insights that may be applicable to these other areas. This assessment has a future focus on the incremental impacts of direct PM2.5 sources within these areas after implementation of the Clean Air Interstate Rule (CAIR), Clean Air Mercury Rule (CAMR), and Clean Air Visibility Rule (CAVR).