The Environmental Protection Agency (EPA) issued a proposed rule related to its review of the existing secondary National Ambient Air Quality Standards (NAAQS) for nitrogen oxides, sulfur oxides, and particulate matter (PM). The proposal would revise the secondary sulfur dioxide standard to an annual average (averaged over three consecutive years) ranging from 10 to 15 parts per billion. The proposal would retain the existing secondary standards for nitrogen oxides and PM. Comments are due June 14.
EPA also announced a virtual public hearing related to the proposed rule. The hearing will be held on May 8
