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 This website is no longer updated and links to external websites and some internal pages may not work.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

Ground-level Ozone Pollution

Implementation of the 2008 Ozone National Ambient Air Quality Standard (NAAQS) Memorandum

The purpose of this September 2011 memorandum was to clarify for state and local air agencies the status of the 2008 ozone NAAQS and to outline implementation steps moving forward.

To learn more about the implementation rule, visit the 2008 Ozone NAAQS Implementation Rule page.

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