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 ...

Chicago faces an extreme heat watch with temperatures expected to reach mid-90s and heat indexes up to 115 degrees.

Sensitive groups are advised to stay indoors and limit outdoor activities as pollution and ozone levels spike to unhealthy ...

An air quality alert was issued Thursday by the National Weather Service for the entire Chicago area through Friday night.

The Chicago area recorded ozone levels of 156 late Monday afternoon. Levels above 100 are considered unhealthy. Residents ...

The Illinois Environmental Protection Agency has issued an Air Pollution Action Day for Tuesday, July 15. Here's what to know ...

As of Thursday morning, Chicago, Detroit and Washington, D.C. were ranked as the three cities with the worst air quality in the world, according to IQ Air's Air Quality Index.

ABC7 Chicago's Air Quality Tracker provides real-time updates on the latest air quality data available from government monitors across the region. ... The air quality index breaks down as follows: ...

The Illinois EPA declared an Air Pollution Action Day in the Chicago metro area. See today's air quality index forecast for Illinois.

The World Air Quality Index reported, Chicago had the worst air quality on Tuesday. That group marked Chicago's air "unhealthy," and in the red zone. According to CBS 2 meteorologists, ...

By 12:30 p.m., the Air Quality Index had reached unhealthy levels in the entire Chicago area, with AirNow.gov showing the city with an AQI of 163, the north and west suburbs with an AQI of 158 and ...