The U.S. EPA conducts modeling analyses to support policy and regulatory decisions using the full range of air quality models and other mathematical simulation techniques used in assessing control strategies and source culpability. Support of national and regional-scale rulemakings with technical support documents and model evaluation reports as well as model comparison reports for dispersion models are available at Reports and Journal Articles. This site provides more detailed information on these regulatory and non-regulatory applications including descriptions of projects, presentations, tabular summaries and graphics of model inputs and predictions, and links to EPA's ftp download area for accessing selected input and output files. In addition, this site provides access to EPA developed tools for potential use in State Implementation Plan (SIP) demonstrations and other air quality modeling assessments.

Photochemical Modeling Applications - Provides access to modeling applications involving photochemical models, including modeling of ozone, particulate matter (PM), and mercury for national and regional EPA regulations such as the Clean Air Interstate Rule (CAIR) and the Clean Air Mercury Rule (CAMR).

Photochemical Modeling Tools - Provides access to to tools for use in State Implementation Plan (SIP) demonstrations and other air quality modeling assessments, including the Modeled Attainment Test Software (MATS).

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

Multipollutant Modeling Applications - Provides access to information on modeling applications involving both photochemical models and dispersion models applied for both criteria and air toxic pollutants.