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Particulate Matter (PM) Pollution

National Ambient Air Quality Standards (NAAQS) for PM

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Rule Summary

On June 10, 2021, EPA announced it will reconsider the December 2020 decision described below.

On December 7, 2020, after carefully reviewing the most recent available scientific evidence and technical information, and consulting with the Agency’s independent scientific advisors, EPA announced its decision to retain, without revision, the existing primary (health-based) and secondary (welfare-based) National Ambient Air Quality Standards (NAAQS) for particulate matter.

Currently, the EPA has primary and secondary standards for PM2.5 (annual average standards with levels of 12.0 µg/m3 and 15.0 µg/m3, respectively; 24-hour standards with 98th percentile forms and levels of 35 µg/m3) and PM10 (24-hour standards with one-expected exceedance forms and levels of 150 µg/m3). 

Rule History

12/07/2020 - Final Decision (signed 12/4/2020)

04/29/2020 - Public Hearing Notice

04/14/2020 – Proposed Action

01/15/2013 – Final Decision in the 2012 PM NAAQS Review

Additional Resources

Fact Sheet Summarizing Final Action

Scientific and Technical Documents 

Information on the Review of Secondary Standards for Ecological Effects of Oxides of Nitrogen, Oxides of Sulfur and Particulate Matter