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Sulfur Dioxide (SO2) Pollution

Fact Sheets and Additional Information Regarding the 2012 Decision to Retain the Secondary NAAQS for Nitrogen Dioxide and Sulfur Dioxide

On April 3, 2012, EPA decided to retain the current secondary national ambient air quality standard (NAAQS) for nitrogen dioxide (NO2) and sulfur dioxide (SO2).

This page contains a fact sheet and a presentation describing that action.

For more information, visit the 2012 NO2 and SO2 NAAQS 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.