Particle Pollution Designations Regulatory Actions
EPA Provided Notice of Intended Approach for Finalizing Area Designations for the 2024 Revised PM2.5 NAAQS
October 2, 2026 – EPA provided notice of its issuance of letters to States, territories, and certain Tribes notifying them as to whether EPA may modify the state, territory, or Tribe’s initial area designations for the revised 2024 annual fine particulate matter (PM2.5) National Ambient Air Quality Standard (NAAQS or standard).
EPA Finalizes the 2024 Revised Primary Annual PM2.5 NAAQS
February 7, 2024 - The EPA promulgated a revised primary annual PM2.5 NAAQS, strengthening it from 12.0 micrograms per cubic meter (μg/m3) to 9.0 μg/m3; retained the existing 24-hour PM2.5 standard at 35 μg/m3; retained the existing 24-hour PM10 (coarse particle) standard at 150 μg/m3; and retained the current suite of secondary PM standards.
The following contains a chronological listing of all regulatory actions related to designations for the 2012 particle pollution standard.
Final Air Quality Designations for the 2012 Annual PM2.5 Standard for Remaining Areas in Florida
July 31, 2018 - EPA designates the five remaining counties in Florida as unclassifiable/attainment.
Final Area Designations for the 2012 Annual PM2.5 Standard for Areas in Tennessee
May 10, 2017 - EPA issues initial designations for areas in Tennessee for the 2012 primary annual national ambient air quality standard for fine particle pollution.
Final Area Designations for the 2012 Annual PM2.5 Standard for Areas in Georgia and Florida
August 30, 2016 - EPA issues initial designations for certain areas in Georgia and Florida for the 2012 primary annual national ambient air quality standard for fine particle pollution.
Additional Final Area Designations and Technical Amendment for the 2012 Annual PM2.5 Standard
March 31, 2015 - EPA is establishing or revising initial area designations and a technical amendment to correct an inadvertent error in the initial designation for one area for the 2012 annual national ambient air quality standards for fine particle pollution.
EPA Finalizes Initial Area Designations for the 2012 National Air Quality Standard for PM2.5
December 18, 2014 - After considering state and tribal recommendations, reviewing the most recent certified fine particle air quality data, and emissions that contribute fine particle pollution, EPA has completed initial designations for the 2012 annual fine particle standard.
Recommended Area Designations for the 2012 National Air Quality Standards for PM2.5
August 19, 2014 - In response to recommendations from state and tribal representatives, EPA sent letters outlining the areas it’s intended designations for the annual fine particle air quality standards set in 2012.