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 Tuesday morning, the Air Quality Index in Milwaukee was between 115 to 120, which falls in the "unhealthy for sensitive groups" category.

Milwaukee, Ozaukee, Racine, Kenosha and Sheboygan are all under a poor air quality alert from noon to 11 p.m., according to ...

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 ...

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.