Finding Annual PM Limit ‘Controlling,’ EPA Declines To Tighten Daily Limit

EPA’s decision to retain its daily limit for fine particulate matter (PM2.5) confirms a split with health advocates and science advisors who argued that a tighter short-term limit could more effectively reduce harmful air pollution spikes from wildfires and other events, as the agency finds an annual limit “controlling.” In its Feb. 7 final rule tightening national ambient air quality standards (NAAQS) for PM2.5, EPA revises the annual standard from 12 micrograms per cubic meter (ug/m3) to 9 ug/m3, but...