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 This website is no longer updated and links to external websites and some internal pages may not work.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

Nitrogen Dioxide Designations

Nitrogen Dioxide Designations - Final Designations for 2010 Standard

January 20, 2012 – Based on the most recent air quality monitoring data (2008-2010), EPA has designated all areas of the country as unclassifiable/attainment.

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