An air quality alert was issued by the National Weather Service in Mount Holly at 9:43 a.m. on Friday, Aug. 15.

Allegheny County is increasing air quality monitoring after an explosion at a U.S. Steel plant south of Pittsburgh killed two ...

The Trump administration is backing a trucking industry lawsuit against the state’s plan to lower emissions and switch to electric vehicles.

Official air-quality results for Kyrene de la Sierra Elementary School show elevated levels of potentially harmful chemicals.

The health department began deploying mobile air units Thursday provided by Pennsylvania’s Department of Environmental ...