Canadian Wildfire Smoke Prompting Air Quality Alerts for Chicago, Detroit, and New York City

Air quality in several major U.S. cities takes a hit again today as smoke from Canadian wildfires continues to sink south into the country. Chicago’s air quality is among the worst for major cities worldwide.

Particle pollution forecast for 5 PM Thursday.
Particle pollution forecast for 5 PM Thursday.

As of early Thursday, Chicago’s air quality was in the unhealthy category, level four out of six, with six, the hazardous category, the worst. Chicago’s AQI of 166 meant the Windy City had the second-worst air quality for any major city around the world, according to IQAir’s rankings. Only Dakar, Senegal, with an AQI of 191, also in the unhealthy category, was worse.

“Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects,” is how the Environmental Protection Agency describes the unhealthy category. Detroit also cracked the top 20 list for worst-polluted major cities, coming in 16th on the list with an AQI of 87, placing the city’s air quality in the moderate category, level two out of six.

Alerts from Nebraska to New York

Air quality alerts were in effect on Thursday for seven states, primarily in the Midwest, with a few along the East Coast as well. In addition to Chicago and Detroit, other large cities in the U.S. are under alerts for air quality, including Milwaukee, Omaha, Green Bay, and Des Moines. “Active children and adults, especially people with pulmonary or respiratory disease such as asthma, should limit prolonged outdoor activity,” reads the alert for Chicago.

Smoke from numerous active wildfires in Canada is being carried southward into the U.S., creating beautiful sunsets in several northern states, but also bringing harmful air pollution. Chicago’s airborne particulate matter with a diameter of 2.5 micrometers, or PM2.5 concentration, was “15 times the World Health Organization annual PM2.5 guideline value” on Thursday, according to IQAir.

Canada is Not the Only Source of Smoke This Year

The Canadian Interagency Forest Fire Centre Inc. (CIFFC) reported there were over 200 active fires burning across Canada on Thursday, and nearly half of them were out of control. Over 1700 fires have burned more than 6 million acres in Canada through early June. That is nearly six times the amount of acres burned by this time in 2024 and more than five times the number of acres that have burned in the United States so far this year.

The smoke in the skies this year over the northern U.S. isn’t coming just from Canada. Several active wildfires are burning in Minnesota. The Jenkins Creek Fire is one of the worst the state has seen this year, having burned over 16,000 acres. It was 94% contained early today.

Wisconsin has also experienced an active year for wildfires. So far, the state has reported 900 fires in 2025, compared to the 10-year average year-to-date of 569. Michigan's wildfire has reported 229 fires so far this year compared. The state sees just over 300 in an average year.

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