Stay inside as much as possible, experts warn, as Chicago fills with smoke from Canadian wildfires. Children, senior citizens, and people with preexisting conditions are especially at risk from this week’s air pollution
Chicago ranks among the worst air quality in the world today. Skies are hazy, and a smoky scent lingers in the air due to drifting smoke from Canadian wildfires.
The National Weather Service issued an Air Quality Alert for the Chicagoland area, calling for everyone — especially children, older adults, and people with pulmonary or respiratory diseases such as asthma — to avoid “prolonged activities or heavy exertion outdoors.” All of the city’s outdoor pools and beaches have closed due to the hazardous air.
The worst time of day for air pollution is mid-day, when the most people and vehicles are out and about, says Sheetal Khedkar Rao, MD, assistant professor of medicine at the University of Illinois Chicago. As of 3 p.m., the Air Quality Index in Chicago reached 597. Anything over 300 is categorized as hazardous.
The alert covers most of the Chicagoland area, but the northern suburbs and neighborhoods bordering Lake Michigan will have the worst air quality. Fox 32 Chicago meteorologist Mike Caplan predicted the smoke will persist through Friday, although it might thin slightly. The weather service said the smoke will likely “meander in and out of” northern Illinois on Friday.
In River North, workers and tourists walked the streets as usual, though outdoor seating at usually bustling restaurants sat empty. Inside the Jewel-Osco at State Street and Grand Avenue, many masked residents expressed worry about today’s conditions. “It’s terrible,” one woman said. “You can smell it outside like something’s burning.”
How you can protect yourself
The most effective masks for air pollution protection are N95 and KN95, says IQAir, a Swiss company that provides global air quality monitoring. The mask should be tight-fitting and have an effective seal. Fabric masks and surgical masks used to prevent disease transmission are not effective for air pollution.
Brandon Koretz lives in River North. He wore a mask to work and to grocery shop — something he learned during past air pollution events that reached Chicago.
“Fortunately I have some N95 masks in my apartment from Covid, which has come in handy,” he says.
Santina Wheat, MD, program director of the McGaw Northwestern Family Medicine Residency at Delnor Hospital, says other than wearing a mask, she recommends that people change clothes after returning home from outside as particulates can linger on clothing.
She also says to close windows and to use air conditioners, if possible. Air conditioners with an option to recirculate air inside the home or car are ideal. And during wildfire season, make sure to change the filters on your air conditioner or HVAC systems.
For those without access to healthy air at home, libraries and city-operated Community Service Centers are open to the public during the day.
Symptoms to watch for
AccuWeather forecasts Chicago will reach a high of 92°F today. The combination of poor air and high temperatures carries additional risks. Consistent hot air causes pollution to stagnate in the lower atmosphere, dissipating more slowly than it would under cooler conditions.
People with existing lung diseases, including asthma and chronic obstructive pulmonary disease (COPD), should be extremely cautious, as should those with heart conditions or diabetes. Air pollution and high heat “both cause blood sugar to increase, having a synergistic impact on health,” Rao says.
Air pollution also can cause eye irritation, headaches, and dizziness. People with underlying conditions should take symptoms like shortness of breath, chest pain, and dizziness more seriously, and consider seeking medical attention, Rao says.
She’s especially concerned today for outdoor workers, who may be outdoors for long periods without protective equipment. She recommended business owners supply employees with K95 masks and warn them of the risks. “I know I don’t need my lawn mowed today,” she says. “Let’s prioritize health.”
At River North’s Jewel-Osco, two bike couriers stood outside with their bikes. Typically, 20 or so couriers fill the sidewalk, but at 1 p.m. only Jason and Kevin were there. They’d been out since 7 a.m. and will work until midnight.
They say they’re worried about the air but that they need to work. “It’s toxic, and we’re all day in the street,” Jason says.
They both carry masks, but after so many hours in the heat, they say the masks get annoying.
Rao additionally cautions working parents to communicate to caregivers that their children should stay indoors. “Kids are at higher risks because they breathe more frequently and are closer to the ground, where more pollutants might be concentrated,” she says. “Any harm that happens to their health at this age can carry forward, especially with repeated exposure over time like what we’re seeing.”
This is the third day in three years that Chicago has been one of the worst cities in the world for air pollution, registering an AQI of 175 on June 27, 2023 and 174 on July 31, 2025.
“We are seeing a lot more wildfire smoke in Chicagoland because of the changing climate,” says Rao, who is also a co-investigator at University of Illinois Chicago’s Center for Extreme Conditions and Health Excellence. “When an acute event happens frequently, it has chronic effects.”
In one Northwest Side moms’ group on Facebook, multiple posts popped up with people asking whether others were keeping their children home from camps due to the air quality. Nearly 100 people responded — a mix of people keeping their children home, people reporting that their camps were moving indoors, and people worried because they had to work and had no other option but to send their children to camp.
Long-term wildfire smoke effects
Wildfire smoke contains particulate matter, which is composed of fine pieces of dust, dirt, soot, smoke, droplets of liquid, and other pollutants, says the American Lung Association. The particulates infiltrate the lungs’ air sacs, damaging them and causing lung disease. From the lungs, the particulates can pass into the bloodstream and cause harm throughout the body potentially leading to pneumonia, heart disease, and strokes.
Wheat says the long-term effects will vary person-to-person, but for vulnerable populations, breathing in irritants from wildfire smoke could trigger a chronic issue down the line.
“I won’t be surprised in future years if we’re doing additional screenings or if more people are needing inhalers to help them breathe,” she says.
The lungs, to some extent, can repair themselves, especially if a person is able to cough out some of the particulates. But if someone has lung disease or smokes regularly, that repair becomes much harder.
Ultimately, Wheat urges people to reach out to their physician with any concerns about their respiratory health.
Additional reporting by Katie Scarlett Brandt
Rachel Duckett is a freelance health and science writer. A lifelong Midwesterner, she previously hosted All Things Considered at WVIK, Quad Cities NPR in Rock Island, Illinois. She has also worked at an environmental initiative out of Detroit Public Television called Great Lakes Now, covering environmental stories in the Great Lakes Basin, and as a copy editor for the Spartan Medical Research Journal in East Lansing, Michigan. She hopes to demystify research and medicine for a general audience with her writing.
A health journalist and attorney who lives in Chicago, Kimberly covers science, health and the environment as a graduate student at Northwestern’s Medill School of Journalism. She hopes to use her knowledge of public health and law to communicate complex issues to the general public.
