The Clean Air Act requires the EPA to identify and set national ambient air-quality standards to protect people and the environment from pollutants like sulfur oxides, but the agency often drags its ...

created National Ambient Air Quality standards. The two most relevant thresholds are 150 micrograms of pollutants per cubic meter of air over a 24-hour period for coarse particulate matter (PM10 ...

It is time for a regulatory reset,” said an industry-backed letter calling for the new administration to undo or revisit a variety of air rules.