Wildfire smoke from Canada and Minnesota pushes air quality in Illinois to unhealthy levels

Finnegan Belleau, Chicago Tribune on Jul 16, 2026

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CHICAGO — Thick haze settled over northern Illinois on Thursday morning as wildfire smoke from Canada and Minnesota rolled into the area, according to the National Weather Service.

Particulate matter levels in the Chicago area had reached an index of 267 on a scale of 500, which is considered unhealthy for the general public.

Also in this category for Illinois were Aurora and Elgin, Lake County, Chicago’s north and west suburbs, Rockford and Chicago’s south and west suburbs.

Levels between 200 and 300 are “very unhealthy,” and anything between 300 and 500 is “hazardous,” according to AirNow, a website that combines data from county, state and federal air quality agencies nationwide. When the forecast is very unhealthy, everyone needs to cut back on outdoor activities. People with heart or lung disease, older adults, children and teens should avoid physical activities outdoors. Everyone else should avoid strenuous activities outdoors.

According to Swiss air quality company IQAir, as of 9 a.m. Chicago was the fourth most-polluted major city in the world, behind Detroit, Toronto and Minneapolis.

Fine particles known as PM2.5, which can be emitted by factories, power plants, diesel and gasoline vehicles, residential fireplaces and wildfires, are the main driver behind Thursday’s elevated air quality. PM2.5 can harm human health and sometimes be deadly. Initially, fine particulate matter may cause a burning sensation in the eyes and nose. But because of its small size, it can settle deep in the lungs and cross into the bloodstream.

As climate change intensifies, concerns grow about air quality events that disrupt daily life becoming the norm. Scientists say climate change from human activities is making conditions like drought more common, thus increasing the size, frequency and severity of wildfires. Wind patterns also add a layer of unpredictability to the reach of bad air from intensifying, longer-lasting wildfires.

Chicago Park District spokesperson Irene Tostado said the parks will be taking safety precautions for both summer camp participants and outdoor employees. In Evanston, city beaches were closed to swimming. The Naperville Park District closed Centennial Beach for the day due to poor air quality. Summer camps in Evanston, Carpentersville and Naperville reported changing scheduled outdoor activities to inside or canceling them altogether.

—Chicago Tribune’s Evgenia Anastasakos and Daily Herald’s Jake Griffin contributed.

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