AirNow is a collaborative effort of federal agencies that provides air quality data across the U.S. The site also has up-to-date information about the wildfires, resources, data, and interactive maps to help users learn more about particular areas and how they might be affected. There's also a free AirNow mobile app.

Massive wildfires burning in the Los Angeles area have filled the air with a thick cloud of smoke and ash, prompting air quality advisories across a vast stretch of Southern California. Three major fires broke out Tuesday amid dangerously high winds,