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 This website is no longer updated and links to external websites and some internal pages may not work.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 »

IIOAC - Integrated Indoor-Outdoor Air Calculator User's Guide

The Integrated Indoor - Outdoor Air Calculator User's Guide provides a more detailed overview of the IIOAC model, equations used to estimate air concentration and deposition from point and from point and area sources in industrial facilities and water and soil sources. Rationale for defaults is also explained.

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

IIOAC Integrated - Indoor-Outdoor Air Calculator User's Guide (PDF)(89 pp, 3 MB)