While the smoke is worst along the Western Slope where the fires are burning, levels are also fluctuating on the Front Range.

Winds could blow smoke from the Bear Gulch fire burning on the Olympic Peninsula, bringing the potential for unhealthy air ...

Despite thick smoke in the sky today in southern Colorado, air quality alerts haven't been issued - instead they've been in the western slope. In fact - sometimes invisible compounds pose more risk.

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

An air quality alert was reported by the National Weather Service on Tuesday at 12:17 p.m. in effect until 8 p.m. for ...