An air quality alert was issued for the Chicago area through midnight on Wednesday due to lingering Canadian wildfire smoke. 

According to AirNow, Chicago is under "moderate" air quality.  

Residents are advised to take precautions, especially those sensitive to polluted conditions, by limiting their time outside and keeping windows and doors closed.   

Groups most sensitive to the air quality include babies, children, and elderly people. 

During this time, Chicago residents are also urged to reduce pollution levels. You can find tips for lowering pollution levels here. 

On July 31, Canadian wildfire smoke brought the worst air quality in the world to Chicago. According to IQAir, Chicago's air quality index on July 31 was, for a time, standing at 174, the worst of any major city in the world.