On January 27, 2023, the Environmental Protection Agency (EPA) released a reconsideration of the National Ambient Air Quality Standards (NAAQS), proposing a revision to lower the annual standard for particulate matter with an aerodynamic diameter of 2.5 microns or less (PM2.5). The EPA proposed to retain existing 24-hour PM 2.5 and PM 10 standards but is accepting comments on lowering the 24-hour PM 2.5 standard in the future by as much as 10 ug/m3.
The Clean Air Act (CAA), authorizing EPA to enact the NAAQS, is the bedrock from which air quality regulation is derived in the United States. When a region (e.g., state, county, metropolitan area) fails to meet any of the NAAQS, they will be classified in ‘nonattainment’ for that pollutant.
The proposed rule would establish a reduction in the annual PM2.5 NAAQS by up to 20% from the current NAAQS of 12.0 µg/m3, setting the new standard for annual PM2.5 in the range of 9.0 to 10.0 micrograms per cubic meter (µg/m3).
Areas that fall into nonattainment are required to submit an updated State Implementation Plan that includes revisions to permitting, operational, and emissions control requirements that are intended to provide the necessary framework for returning the area to attainment with the NAAQS. Further, additional monitoring will be required to address Environmental Justice concerns in nonattainment areas.
The strengthening of the NAAQS at the Federal level may drive changes to local rules, codes, and ordinances with respect to air quality; and with it, a greater need for air monitoring. This will be a concern particularly in areas with 10-12 µg/m3 PM2.5, which will be freshly reclassified as nonattainment areas.
Although this new standard should not affect ongoing perimeter air monitoring programs, which routinely employ monitoring of PM10, AirLogics equipment is fully capable of monitoring and detecting PM2.5 at the new lower levels. AirLogics utilizes “near reference” monitors, to provide a monitoring approach that balances cost and data quality to develop robust, accurate and reliable monitoring programs. Further, AirLogics is prepared to provide support for air monitoring programs amidst the changing regulatory environment.