Learn what the air quality index (AQI) means, how it impacts your health, and how to stay safe when pollution is high.

The Air Quality Index, set by the Environmental Protection Agency, is your guide to how bad the air quality is outdoors. The data that goes into the Air Quality Index comes from 5,000 air monitors ...

But air quality can vary on a hyperlocal scale, meaning the network of official sites is "fairly sparse," says Michael ... really happening on the kind of localized level that really matters to people ...

Angelenos still bothered by the smell of smoke may be surprised to see that Air Quality Index numbers returned ... or are in an area with high AQI levels. That means don’t exercise, keep your ...

Those groups particularly sensitive to particulate matter in the air may want to limit time outside Friday and Saturday.