An official website of the United States government.

This is not the current EPA website. To navigate to the current EPA website, please go to www.epa.gov. This website is historical material reflecting the EPA website as it existed on January 19, 2021. This website is no longer updated and links to external websites and some internal pages may not work. More information »

Air Quality Modeling Technical Support Document for the Proposed Revised Cross-State Air Pollution Rule Update

This TSD provides information on the methods and data used to perform air quality modeling to support the proposed Revised CSAPR Update as well as the resulting model predictions that are used to identify nonattainment and maintenance receptors and interstate linkages that inform steps 1 and 2, respectively, of the four-step transport framework.

You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.