The chief air pollution regulator at the US Environmental Protection Agency is resigning.

The businesses — often housed in no-frills, boxy buildings scattered through industrial districts — dot Southern California, from San Bernardino to Los Angeles. The mom-and-pop-size companies who ...

DIAMOND BAR, Calif. (AP) — Air quality regulators in Southern California voted 7 to 5 to reject rules that would have curbed harmful emissions from gas-powered furnaces and water heaters, but the ...

Reporting for this story was supported by the Nova Institute for Health. In the decades since Congress passed the Clean Air Act in the early 1960s, air quality monitoring has become one of the EPA’s ...

Aaron Szabo will step down as the head of the Environmental Protection Agency’s air office this month, he told employees, ...