Is the air quality good in Chicago?
As of August 6, 2025, the air quality in Chicago is not considered good and is in the range of unhealthy for sensitive groups. The main pollutant contributing to this status is PM2.5.
For a more detailed look, see Chicago’s air quality map.
Chicago is among the most polluted major city in the world, having recently recorded some of the worst air quality levels globally due to wildfire smoke and ozone buildup (3).
Chicago was listed as the 3rd most polluted major city on the morning of August 6. Source: IQAir.
Why is there an air quality alert in Chicago?
The air quality alert in Chicago is due to a combination of pollutants, with two main contributors identified:
- Ground-level ozone: This is currently the primary pollutant impacting Chicago’s air quality. Ozone forms when emissions from vehicles, refineries, power plants, and industrial facilities react in the presence of sunlight. Hot, sunny days can accelerate this reaction, leading to dangerous ozone buildup (1).
- Canadian wildfire smoke: Smoke from over 700 wildfires currently burning across Canada continues to impact Chicago and the broader Midwest region. While winds have shifted some smoke away, lingering particles remain a concern.
These conditions are exacerbating smog formation and increasing health risks, especially for individuals with respiratory issues.
Hourly air quality forecast for Chicago, Illinois on August 6. Source: IQAir.
Air quality is forecasted to improve in evening.
Which cities are being affected by wildfire smoke?
The following cities and counties in and around Chicago are currently affected by wildfire smoke exposure and elevated ozone levels:
- Cook, Illinois
- DuPage, Illinois
- Grundy, Illinois
- Kane, Illinois
- Kendall, Illinois
- LaPorte, Indiana
- McHenry, Illinois
- Newton, Indiana
- Porter, Indiana
- Will, Illinois
Air quality map of the Chicago on August 6. Source: IQAir.
Are there any alerts in place?
Yes, multiple alerts have been issued across northeastern Illinois and northwest Indiana due to worsening air conditions (2):
- The Illinois Environmental Protection Agency has issued an Air Pollution Action Day for counties including Cook, DuPage, and Lake.
- The National Weather Service has declared air quality alerts for Lake, Porter, LaPorte, Newton, and Jasper counties in Indiana.
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How can I protect myself from poor air quality?
- Get a free air quality app for real-time air quality alerts and forecasts.
- Shut doors and windows and set the HVAC to recirculate mode.
- Contribute to your community’s outdoor air quality data.
- Stay indoors when air quality is poor; if you do need to go outdoors, wear a KN95/FFP2 mask.
- Run a high-performance air purifier to filter particles, gases, and other pollutants.
