Air quality in wildfire-stricken Los Angeles improved on Thursday from hazardous peaks hit earlier this month, as tiny soot particles that can penetrate the lungs and brain dropped to moderate levels,

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.