Already known for having some of the worst air quality in the U.S., people in Southern California are now also at risk of inhaling smoke.

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.

As thousands of acres burn across Southern California, wildfire smoke is causing poor air quality in the region and beyond.