EPA Proposes Significant Change To Particulate Matter Air Quality Standards

On January 6, 2023, EPA announced that is was issuing a proposed rule to lower the National Ambient Air Quality Standards ("NAAQS") for fine particulate matter ("PM2.5"), also referred to as soot. The current primary annual NAAQS for PM2.5 is 12 micrograms per cubic meter (µg/m³). EPA's proposal will accept comments on reducing that annual NAAQS to a level between 9 and 10 µg/m³. EPA is proposing to keep in place the existing secondary annual standard for PM2.5, the primary and secondary 24-hour standards for PM2.5, and the primary and secondary standards for PM10.

The current standards have been in place since 2012, and were most recently reaffirmed by EPA in 2020. Then, in June of 2021, EPA announced it was reconsidering that 2020 decision, starting the process that lead to the current proposed rule. The NAAQS are national air quality goals set by EPA for criteria air pollutants (like particulate matter), at levels that will that will protect the public health