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Final Guidance on Ozone and Fine Particulate Matter Permit Modeling Issued by U.S. EPA

Posted: August 4th, 2022

Authors: Dan D. 

The U.S. EPA Office of Air Quality Planning and Standards (OAQPS) published the “Final Guidance for Ozone and Fine Particulate Matter Permit” (Final Guidance) Modeling on July 29, 2022. The Final Guidance reflects the U.S. EPA’s recommendations for how stationary sources seeking a Prevention of Significant Deterioration (PSD) permit may demonstrate that they will not cause or contribute to a violation of the particulate matter with a diameter of 2.5 microns or less (PM2.5) PSD increment and the PM2.5 and ozone O3 National Ambient Air Quality Standards (NAAQS). The Final Guidance replaces the February 10, 2020 draft and September 20, 2021 revised guidance discussed in my October 8, 2021 blog post. There were no major changes from the September 20, 2021, revised guidance to this new Final Guidance. As discussed in my October 8, 2021 blog post the most significant impact of this guidance is the requirement to conduct direct PM2.5 modeling if an applicant triggers the PSD significant emissions rates for PM2.5 precursors nitrogen oxide (NOX) or sulfur dioxide (SO2), even if the applicant does not trigger for PM2.5 itself. The U.S. EPA is conducting a release webinar on August 11, 2022, to provide an overview of the Final Guidance and allow for an open exchange on the final version of the guidance that ALL4 will be attending.

In addition to the Final Guidance setting new triggers for conducting PM2.5 modeling, also be aware that U.S. EPA is currently reconsidering the PM2.5 NAAQS and we expect to see a proposed lower annual PM2.5 NAAQS between 8-11 micrograms per cubic meter (mg/m3) by the end of the summer.

If you have any questions about how a potential project that includes PM2.5 emissions will be impacted by the Final Guidance or lowered PM2.5 NAAQS, please contact Dan Dix at ddix@all4inc.com or at 610.422.1118.

Additional PM2.5 Resources


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