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Latest EPA Proposal for National Ambient  Air Quality Standards Long Overdue

Latest EPA Proposal for National Ambient Air Quality Standards Long Overdue

Latest EPA Proposal for National Ambient
Air Quality Standards Long Overdue

Is Being Proactive Your Next Step?


Staying up-to-date and prepared for changes to regulatory standards is essential to maintaining a healthy and safe working environment. QTS’ team of experts continually monitor various governing agencies to help our clients stay ahead of what may be expected of them.

The Clean Air Act requires EPA to periodically review the standards to ensure that they provide adequate health and environmental protection, and to update those standards as necessary. To that end, on January 6, 2023 EPA announced their proposed decision to the revise the National Ambient Air Quality Standards.

Proposed Changes to Particulate Matter Levels

EPA proposed to change Particulate Matter (PM) 2.5 from its current level of 12.0 µg/m3 to within a lower range of 9.0 to 10.0 µg/m3.  In addition, EPA proposed revisions to other key aspects related to the PM NAAQS, including revisions to the Air Quality Index (AQI) and monitoring requirements.

PM2.5 is the fine particulate fraction in air with diameters equal to or less the 2.5 microns that can be inhaled deep into the lungs, causing adverse effects.  Since 1997 when EPA first decreed the Ambient Air Quality Standard (AAQS) for PM2.5, concerns by some in the environmental health community were raised as to the protectiveness of the standard.

As required by law for revision, EPA’s recent assessment concluded that the health effects associated with exposure to fine particles are significant. EPA cites epidemiological studies that have shown a significant correlation between elevated fine particle levels and premature mortality. Other important effects associated with fine particle exposure include aggravation of respiratory and cardiovascular disease (as indicated by increased hospital admissions, emergency room visits, absences from school or work, and restricted activity days), lung disease, decreased lung function, asthma attacks, and certain cardiovascular problems such as heart attacks and cardiac arrhythmia Individuals particularly sensitive to fine particle exposure include older adults, people with heart and lung disease, and children.

EPA determined in their assessment that documented scientific information incites the necessity to review and assess the current primary annual PM2.5 standard and that it is appropriate to consider strengthening this standard.

In rendering its recommendation, EPA cited that ”recent studies suggest adverse health effects from exposure to PM2.5 are occurring at concentrations allowed by the current standards.

  • Additional studies are demonstrating improvements in public health, including reductions in mortality, following reductions in PM2.5 in areas with air quality below current standards,” hence why the lowered standards are of merit.
  • EPA’s quantitative risk assessment estimates that the current primary standards could allow thousands of PM2.5- associated deaths per year.”

Lowering PM 2.5 from 12.0 µg/m3 to within the range of 9.0

to 10.0 µg/m3 is most related to combustion processes. The major source of PM2.5 comes from vehicle exhausts, operations that involve the burning of fuels such as wood, heating oil or coal, and natural sources such as forest and grass fires.

How Your Industry May Be Impacted

Fine particles can form from the reaction of gases or droplets in the atmosphere from sources such as power plants. The proposed regulated communities most affected are those subject to air permits and monitoring under the Clean Air Act.  Coal-fired power plants and refineries are recognized as major stationary sources of PM2.5 and subject to Clean Air Act.

This also affects source operations in nonattainment areas under Clean Air Act. When an area does not meet the standard, it is classified as being in “nonattainment.” This classification impacts businesses that want to locate or expand an air pollution source in their geographical area. The EPA requires three years of data showing that it meets the standard at which time the governing State must petition U.S. EPA to reclassify it as being in attainment.

Construction is usually associated with larger particulate material, however, according to the EPA, construction equipment usage at transportation projects is a source of both fine (PM2. 5) and coarse (PM10) particulate matter. Exhaust from diesel-powered construction equipment includes fine particles (primary PM2. 5) and other pollutants that contribute to the formation of PM2.

Manufacturing and other production operations are affected by the proposed PM 2.4 emissions such as metal production industry (smelters and ore processing) and chemical production and processing.

With recent public hearings taking place, the bottom line is being proactive is key. QTS can assist in an Air Quality Action Plan to ensure your operations is ready ahead of the regulation going into effect, once approved.

What’s Not Changing 

EPA proposed not to change the current:

  • secondary (welfare-based) annual PM2.5 standard,
  • primary and secondary 24-hour PM2.5 standards, and
  • primary and secondary PM10 standards.