AQI: Good (0 - 50) AQI: Good (0 - 50)
Air quality is considered satisfactory, and air pollution poses little or no risk.
AQI: Moderate (51 - 100) AQI: Moderate (51 - 100)
Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of people who are unusually sensitive to air pollution.
AQI: Unhealthy for Sensitive Groups (101 - 150) AQI: Unhealthy for Sensitive Groups (101 - 150)
Although general public is not likely to be affected at this AQI range, people with lung disease, older adults and children are at a greater risk from exposure to ozone, whereas persons with heart and lung disease, older adults and children are at greater risk from the presence of particles in the air.
AQI: Unhealthy (151 - 200) AQI: Unhealthy (151 - 200)
Everyone may begin to experience health effects members of sensitive groups may experience more serious health effects.
 AQI:Very Unhealthy (201 - 300) AQI: Very Unhealthy (201 - 300)
Health alert: everyone may experience more serious health effects.
AQI: Hazardous(301 - 500) AQI: Hazardous (301 - 500)
Health warnings of emergency conditions. The entire population is more likely to be affected.
Action DayAction Day
 
Local Air Quality Resources
Forecast | Real-time Ozone Data Program | Today's AQI
 
State Air Quality Resources
Illinois EPA - Air Quality Index (AQI)
Illinois EPA - Air Quality Information
Illinois EPA - Bureau of Air
Illinois EPA - Contact Information
Illinois Environmental Protection Agency (EPA)
Partners for Clean Air
Respiratory Health Association of Metropolitan Chicago
Daily AQI
Wednesday, January 09, 2013
Particles PM2.5
29 
Good
Particles PM10 Not Available
Ozone
25 
Good
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Note: data are available beginning August 1, 2010.

Other Information
Current Conditions and Forecasts
Air Quality Maps Archives (by region)