Chicago’s Air Quality Is ‘Unhealthy’ Due to Canadian Wildfire Smoke. Here’s What That Really Means

Patty Wetli | July 31, 2025, 5:36 pm

Smoke from Canadian wildfires affected air quality across the Upper Midwest. (IQ Air)

Smoke from Canadian wildfires settled over Chicago Thursday, with air quality reaching “unhealthy” levels for everyone.

The Illinois Environmental Protection Agency issued an air quality alert for northern Illinois through the overnight hours, with conditions expected to improve Friday.

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Though Chicago’s air quality was among the worst of major cities being monitored, the situation was far worse in parts of Canada close to the wildfires. Locations in Saskatchewan, for example, had “hazardous” air quality, with residents being told to avoid all outdoor activity.

In June 2023, Chicago’s air quality reached “very unhealthy” levels.

The poor air quality alert arrived just as tens of thousands of concertgoers converged on Chicago for the opening day of the Lollapalooza music festival.

Here’s what “unhealthy” means:

— Sensitive groups including children, the elderly and people with heart and/or lung conditions should avoid long or intense outdoor activities. Consider rescheduling or moving activities indoors.

— Everyone else should reduce long or intense activities and take more breaks during outdoor activities.