The U.S. Environmental Protection Agency is expected to announce Thursday it is tightening the air quality standards for ground-level ozone from 75 parts per billion to 70 ppb, according to the Associated Press.
Under the new level, the Treasure Valley just skirts nonattainment.
The Treasure Valley’s ozone-pollution levels are fairly consistently in the 67 ppb to 68 ppb range, according to Idaho Department of Environmental Quality. The most recent three-year average for the Valley is 69 ppb.
Areas designated nonattainment must submit an air quality plan to the EPA showing how they will attain the standards. If the plan does not pass muster with the EPA, or if the area fails to implement the plan, it faces Clean Air Act-required sanctions and other penalties, including loss of highway funds and possible restrictions on development.