An official website of the United States government.

We've made some changes to 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)

Nitrogen Dioxide (NO2) and Sulfur Dioxide (SO2) Secondary Standards - Federal Register Notices from Current Review

Over the course of each NAAQS review, EPA publishes notices in the Federal Register for a variety of activities:  the kick-off workshop and call for information, CASAC meetings, availability of pre-rulemaking documents and opportunities for comment on these documents, as well as proposed and final rulemaking decisions and public hearings on a proposed rulemaking decision.

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

Rulemaking Notices / Public Hearings

  • None at this time.

Pre-Rulemaking Documents / Availability and Opportunities for Public Comment

Public Meetings / Workshops

You may also be interested in other documents from the current nitrogen dioxide and sulfur dioxide secondary standards NAAQS review.