A federal court says the Environmental Protection Agency must approve a state plan for reducing fine particulate pollution, like soot, across Arizona — or put forth one of its own.

The Tucson-based Center for Biological Diversity and the Center for Environmental Health of Atlanta, Georgia, filed the suit against Andrew R. Wheeler, in his official capacity as EPA administrator, on March 26, 2019. 

The Clean Air Act requires states submit a plan regulating how air pollution sources may be built or altered, including a permitting process.

The goal is to align such activities with national air quality standards.

If the EPA rejects all or part of that plan, and if the state fails to address the federal agency's concerns, then the law requires the EPA put out a plan of its own within two years.

But when the Arizona Department of Environmental Quality only partially addressed the agency's concerns about its plan, the EPA let it stand.

The settlement, issued by the U.S. District Court for the Northern District of California, Oakland Division, requires the EPA meet its legal obligations by June 30, 2021.