Wildfire Smoke Triggers Chicago Air Alert

Canadian wildfire smoke pushed air quality across the Chicago area into dangerous territory, prompting government warnings for residents to limit time outdoors.

The haze, which brought a strong smoky smell to parts of the city, moved south from Canada and affected much of the region. The National Weather Service said the air quality alert was expected to remain in effect through Saturday, with smoke possibly lingering into Saturday morning.

Government officials warned that the polluted air could be unsafe for anyone spending long periods outside. Beaches in Chicago and Evanston were closed because of the poor air quality, and Chicago Park District outdoor programs were moved indoors. Some event organizers were also weighing whether to cancel activities scheduled later in the day.

The smoke is tied to more than 800 wildfires burning in Canada, many of them out of control. The National Weather Service said some fires are near the northern U.S. border, with wind patterns carrying smoke into Illinois and the broader Midwest.

The Illinois Environmental Protection Agency declared an Air Pollution Action Day for Chicago and Northern Illinois. Residents were urged to reduce prolonged outdoor activity and take more frequent breaks.

Chicago’s Air Quality Index ranged from “very unhealthy” to “hazardous,” the two most severe levels on the AQI scale. A city air-monitoring map showed “very unhealthy” conditions across much of Chicago, with “hazardous” readings in several North Side neighborhoods, including Rogers Park, Edgewater, West Ridge and Lake View. Very unhealthy conditions also extended to South Chicago and Hegewisch.

Fine particle pollution, known as PM 2.5, is the main health concern from wildfire smoke. The microscopic particles can travel deep into the lungs and enter the bloodstream. Health experts say the pollution is especially dangerous for people with asthma, other respiratory conditions, heart risks or weakened immune systems. Pregnant women, children, teenagers and older adults are also considered more vulnerable.

As of Friday morning, Chicago ranked as the worst major city in the world for air pollution, followed by Detroit, Washington, D.C., and New York, according to a Swiss company that sells air purifiers.

Residents can check local air quality by ZIP code through the EPA’s AirNow website.

Forecasters said conditions should improve as the smoke shifts northeast, but the exact timing remained uncertain.

“Based on the latest forecast trends, it looks like air quality should gradually improve as that smoke pushes off to the northeast,” said Zachary Yack, a meteorologist with the National Weather Service. “The only caveat is it’s a little unclear how fast things actually improve.”

Yack also said smoke could linger near Lake Michigan before fully moving out of the area.

Similar wildfire smoke events have affected Chicago in recent years, including in 2023 and again last June, when the city’s air ranked among the worst in the world. The pattern has raised concerns that smoke from Canadian wildfires could become a recurring summer problem as warmer spring temperatures and dry conditions contribute to earlier and more intense fire seasons in Canada.

Health officials advised residents to stay indoors when possible, keep windows and doors closed, and use an N95 mask if they need to be outside.

“I think everyone should close their doors and windows to try to prevent the smoke from getting into their homes as much as possible,” said Dr. Jack Zhao, a pulmonary critical care doctor at Rush Copley Medical Center. “I equate being outside with a forest fire to smoking. I think over time it will cause long-term side effects.”