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

The air quality is poor today in northern Illinois due to migrating Canadian wildfire smoke. See the AQI in your area.

Air quality in all of Central Illinois is considered good, with an Air Quality Index in the high teens to 20 in Bloomington-Normal, Decatur and Mattoon-Charleston.

The building heat and humidity comes as Chicago's air quality readings early Monday morning were "unhealthy for sensitive groups.

Cook County is under a heat watch through Thursday evening. Temperatures could feel like 105-110 degrees Wednesday.

Air quality is unhealthier-than-average for some people Thursday as winds are blowing wildfire smoke across the Northern California region.

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

Wildfires are challenging air quality monitoring infrastructure Can the US's system to monitor air pollutants keep up with a changing climate?

An air quality alert in effect for northwest and north central Minnesota could extend into the weekend as wildfire smoke moves across the state.

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