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 ...

As of Wednesday, more than 400 wildfires were burning across Canada, leading to air quality alerts − indicators the air is unsafe to breathe for certain people − across much of the eastern U.S.

The DEC has issued an air quality health advisory for most of upstate New York due to elevated levels of fine particulate ...

The building heat and humidity comes as Chicago's air quality readings early Monday morning were "unhealthy for sensitive groups," the website AirNow.gov said. The air quality ranked as a level three ...

AirNow and PurpleAir use the Air Quality Index, or A.Q.I., a measure of air quality from 0 to 500 that is composed of six categories, from “good” to “hazardous.” ...

Fine particle levels are expected to reach the purple air quality index category, which means it is considered “very ...

The Air Quality Index (AQI) is used by various government agencies to report how clean or polluted the air is in your area. For example, you may have spotted this metric popping up in local ...

Unhealthy Air Quality Index level. Red: Indexes in the 151 to 200 range are considered "unhealthy." At this level, any member of the general public becomes susceptible to health effects.