An official website of the United States government.

We've made some changes to EPA.gov. If the information you are looking for is not here, you may be able to find it on the EPA Web Archive or the January 19, 2017 Web Snapshot.

Reviewing National Ambient Air Quality Standards (NAAQS)

Contact Us

Review of the National Ambient Air Quality Standards for Oxides of Nitrogen, Proposed Decision

Review of the National Ambient Air Quality Standards for Oxides of Nitrogen, Proposed Decision

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

Review of the National Ambient Air Quality Standards for Oxides of Nitrogen, Proposed Decision (PDF)(159 pp, 688 K, July 2017)