The EPA's Air Quality Index can tell you whether breathing outside air can be harmful. Here's how to read the scale to plan ...

Sorely missed blue skies are returning and cities across the northeastern US are experiencing better air quality indexes after the monstrous cloud of smoke spewed by the wildfires in Canada ...

The U.S. Air Quality Index (AQI) is the Environmental Protection Agency’s tool for reporting outdoor air quality and health.

The EPA's air-quality index (AQI) measures how safe, unhealthy, or hazardous the air is outside. Here's a guide on how to read AQI.

Cities across the US, particularly those in California where wildfires are common, are often exposed to lower air quality due to a mix of urban pollution and weather effects. But even some rural ...

The AQI complication on an Apple Watch measures the Air Quality Index in your area. Here's how the EPA calculates it, and how to use it on your watch.