Calculating air pollution from wildfires and other events has become more complicated. That doesn’t mean it’s necessarily more accurate.

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.

The hazardous air quality in Los Angeles is largely a result of smoke from the Pacific Palisades Fire, intensified by strong Santa Ana winds.