An environmental group has petitioned the federal government to reduce air pollutants in eight western states.
WildEarth Guardians says that by law, the Environmental Protection Agency has to designate areas as "nonattainment" areas if they violate certain air-quality standards and put them on the path to cleaning up.
The group's petition contends 15 areas should be labeled nonattainment areas for violating standards limiting particulate matter to less than 10 microns in diameter, or about one-seventh the width of a human hair. It said the EPA should declare six other areas "serious" nonattainment areas.
WildEarth Guardians also wants the EPA to call for Arizona, Colorado, Montana, Nevada, New Mexico, Oklahoma, Utah and Wyoming to revise their state plans for complying with the Clean Air Act.
The EPA had no immediate comment.
WildEarth Guardians' petition argues the following areas should be labeled nonattainment areas: Tucson, Ariz.; Alamosa, Pagosa Springs, Parachute, Durango, Grand Junction and Lamar in Colorado; part of Jefferson County in Montana; Pahrump, Nev.; Deming, Sunland Park, Chaparral and Las Cruces in New Mexico; Tulsa, Okla.; and part of Sweetwater County in Wyoming.
It said Nogales, Paul Spur/Douglas and Yuma in Arizona; Anthony, N.M.; and Salt Lake and Utah counties in Utah should be bumped up from moderate to serious nonattainment areas.