Raging wildfires in Los Angeles killed at least two people, destroyed hundreds of buildings and stretched firefighting resources and water supplies to the limit on Wednesday, as more than 100,000 people were ordered to evacuate.

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.