Chicago Tops World’s Most Polluted Cities As Canadian Wildfire Smoke Drifts Into Midwest

Topline

Chicago became the most polluted city in the world Tuesday, as it remains shrouded in smoke from Canadian wildfires that have choked multiple East Coast and Midwestern cities in the U.S. this month.

Joggers run along the shoreline of Lake Michigan with heavy smoke from the Canadian wildfires in the … [+] background, on June 27, 2023, in Chicago, Illinois. Chicago Mayor Brandon Johnson said in a statement, “The City of Chicago is carefully monitoring and taking precautions as the U.S. Environmental Protection Agency has categorized our Air Quality Index as “unhealthy” due to Canadian wildfire smoke present in the Chicago region. We recommend children, teens, seniors, people with heart or lung disease, and individuals who are pregnant avoid strenuous activities and limit their time outdoors.” (Photo by KAMIL KRZACZYNSKI / AFP) (Photo by KAMIL KRZACZYNSKI/AFP via Getty Images)

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Key Facts

According to air quality tracker IQAir, Chicago’s air quality index currently sits at the “unhealthy” designation with a score of 198—a number followed closely by Minneapolis, which ranks No. 2 on the global air quality list at 162.

Detroit ranks at No. 4 with an AQI score of 128, as it also faces wildfire smoke.

The rest of the top 10 most polluted cities are located outside the United States: Dubai takes the No. 3 spot on the IQAir list while Johannesburg, South Africa, ranks No. 5.

The Environmental Protection Agency’s AirNow tracker marked Chicago at a score of 250, meaning the city’s current air quality is very unhealthy—a category that suggests many should lessen or outright avoid outdoor activities.

Big Number

160 megatons. That’s the amount of carbon emissions that have been released from Canada’s wildfire smoke—the highest figure ever recorded by the EU’s Copernicus Global Fire Assimilation System since it started recording wildfire smoke emissions 20 years ago.

Tangent

The smoke from Canada’s wildfires managed to cross the Atlantic Ocean and drift into Western Europe, Southern Europe and the British Isles, according to Copernicus data. The main concentration of smoke was forecasted to hit Western Europe Monday and continue further east until Thursday.

What To Watch For

It is unclear when the smoke will clear from parts of Illinois, but its neighboring state of Wisconsin forecasts the smoke to last until Thursday, according to an advisory.

Key Background

The smoke in Chicago drifted from some wildfires in Canada, which number nearly 500 as of Tuesday, according to the Canadian Interagency Forest Fire Centre. Canada’s wildfires have produced large masses of smoke for weeks after starting up in May. By early June, the fires drew more attention after smoke drifted to New York City, making it the most polluted city in the world for a short time. City officials canceled all outdoor activities at public schools and issued a health advisory that encouraged people to “consider limiting strenuous outdoor physical activity.” Home games for the New York Yankees and Philadelphia Phillies were postponed due to the “poor air quality.” Live performances were also impacted, as Emmy Award-winning actress Jodie Comer walked offstage during a showing of the Broadway one-woman play Prima Facie because she was having trouble breathing.