Chicago has been grappling with deteriorating air quality, primarily due to the effects of smoke particles from ongoing wildfires in Canada. These tiny, airborne particles, despite encountering light rain in the area, have become more concentrated, leading to unhealthy air quality levels for the general public as of Thursday. This situation has persisted for three consecutive days and has prompted the state to declare its first two air pollution action days of the year.
In recent reports from IQAir, a Swiss air quality technology company, Chicago’s air quality was ranked the worst in the United States on Thursday. At one point, it was noted that the city had the second-worst air quality among major global cities, according to The Washington Post. Ashish Sharma, a professor of atmospheric sciences at the University of Illinois at Urbana-Champaign, provided insights on the matter, explaining that while the rain helped suppress past pollutants, ongoing wildfires continuously bring in new smoke.
As Chicagoans enter the typically warm summer months, they have already experienced severe air quality degradation. Following a rare dust storm that hit in May, the hazy skies resulting from nearby Canadian wildfires are reminiscent of the extensive pollution observed in 2023, when Chicago was recognized as the second-most-polluted major city in the nation. Currently, the problematic smoke primarily originates from wildfires burning in Manitoba, northwest of Winnipeg, which have been active since mid-May.
Residents are left wondering about the summer ahead: will they be confined indoors due to persistent smoke? Zac Adelman, the executive director of the Lake Michigan Air Directors Consortium, addressed these concerns, emphasizing the unpredictability of forecasting air quality disruptions. He refrained from making dire predictions about the upcoming summer days but echoed the Illinois Environmental Protection Agency’s (IEPA) recommendation for residents in several counties including Cook, DuPage, and Kane to limit their outdoor activities.
The air quality reached a concerning index level of 165 on a scale of 500, marked as unhealthy for the general public by mid-afternoon Thursday. Expectations for Friday mirrored this outlook, leading to the extension of the air quality alert by the IEPA through the end of the day on Friday. With levels between 200 and 300 deemed very unhealthy, and those from 300 to 500 categorized as hazardous, the immediate focus remains on the health effects observed during these deteriorating air quality days.
Experts are increasingly worried that such poor air quality events could become the new normal as climate change exacerbates these conditions. While dust storms have often resulted from inadequate land management in agriculture, wildfires have also spiked in frequency and intensity largely due to climate-induced conditions favoring droughts. Sharma highlighted the lengthening wildfire season that starts earlier and potentially extends later into the year, raising alarm over their unavoidable impact on air quality in areas like the Midwest, including Chicago and the Great Lakes.
Wind patterns further complicate how wildfire smoke disperses, making air quality difficult to predict. In summer 2023, upward air systems transported smoke from wildfires in Quebec and Ontario directly into the Great Lakes region, with 37 million acres lost to wildfires that year. The previous summer witnessed lower fire activity, with less than 13 million acres burning without significantly affecting air quality in the Midwest due to differing wind currents.
As of June 2025, 6.5 million acres have already burned in Canada, as reported by the Canadian Interagency Forest Fire Centre. The complexity lies in varying wind flows and pinpointing where wildfires ignited, which will ultimately determine the extent of smoke impacts downwind. Sharma expressed the intricacies of tracking air quality, noting that fires in North America are a constant threat to air clarity.
Fine particulate matter, known as PM2.5, is produced not only by wildfires but also by localized human activities such as vehicle emissions and industrial operations. Recent developments have highlighted regulatory shifts during President Donald Trump’s administration that are reconsidering previous decisions related to PM2.5 air quality standards, which had tightened from 12 to 9 micrograms per cubic meter of air under the Biden administration.
Data from the Illinois EPA indicated that the Chicago metropolitan area did not adhere to these tighter air quality standards from 2021 to 2023, signaling ongoing air quality struggles for the region. There is a stark reality surrounding PM2.5’s effects on health, particularly affecting vulnerable groups such as individuals with respiratory or cardiovascular conditions, children, seniors, and those living in industrially dense neighborhoods. Health officials have noted symptoms associated with PM2.5 exposure, including wheezing, heightened heart rate, fatigue, chest pain, and shortness of breath.
To mitigate exposure, air quality action days encourage residents to refrain from contributing further to pollution levels. Recommendations include avoiding car use, idling vehicles, outdoor gasoline-powered activities, and even cooking methods that may exacerbate indoor air pollution. Energy conservation practices, employing eco-friendly household products, and utilizing air conditioning systems that recirculate air rather than draw it in from outside are also advisable. Those needing to be outdoors are advised to utilize N95 or N100 masks for additional protection.
The city’s Office for Emergency Management and Communications has urged residents lacking proper shelter to take refuge in public spaces such as libraries, senior centers, and community service centers open on Fridays. The specific locations available for shelter include the Englewood Center, Garfield Center, King Center, North Area Center, South Chicago Center, and Trina Davila Center. Furthermore, Chicagoans can access air quality forecasts and sign up for free notifications through the AirNow.gov and EnviroFlash.info platforms.
Overall, as Chicago faces continuing challenges related to air quality compromised by wildfires and pollution, there exists a pressing need for heightened awareness and proactive measures to safeguard public health.
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