Smoke from hundreds of wildfires burning in Canada, along with fires in northern Minnesota, is expected to keep air quality at unhealthy levels across parts of the Midwest, Great Lakes and Northeast on July 17, shrouding cities in haze and prompting warnings that the air outside could be hazardous to breathe.
Air quality alerts remained in effect on July 17 in multiple states, including parts of Minnesota, Wisconsin, Michigan, Illinois, Indiana, Ohio, West Virginia, Pennsylvania, New York, Vermont, New Jersey, Delaware, Maryland, Virginia and the Carolinas, as smoke drifted south, the National Weather Service said. Some of the worst conditions have been concentrated around Detroit, Minneapolis, Chicago and New York in recent days.
Northwest winds have carried smoke across the Great Lakes and into the Northeast this week, producing yellow and hazy skies, reducing visibility and worsening air quality. The weather service has warned that smoke concentrations near the surface could create health risks, particularly for children, older adults and people with heart or respiratory conditions.
Conditions are expected to gradually improve in some areas over the weekend as wind patterns shift. Forecasters caution that smoky conditions could linger in portions of the Midwest and the Northeast.
More relief is expected by early next week as a cold front pushes cleaner air into the region.
Which US cities are seeing the worst air quality?
Forecasters expect smoke to remain widespread across parts of the northeastern quarter of the country on July 17.
On July 16, smoke levels were dangerous across Minnesota, Michigan, northern Illinois, northern Ohio and into Ontario, with hazardous readings in major cities such as Minneapolis, Milwaukee and Toronto.
Chicago, Detroit, Minneapolis and New York were among the cities reporting some of the worst air quality levels in the world on July 16, according to monitoring company IQAir.
According to the Minnesota Pollution Control Agency, PM2.5 concentrations, the tiny pollution particulates found in wildfire smoke, in parts of northeastern Minnesota peaked near 900 micrograms per cubic meter on July 16, far above levels considered hazardous to public health.
The agency issued an air quality alert through July 17 for east-central, central, west-central, southeast, north-central, northwest and northeast Minnesota.
“Heavy smoke will continue to disperse and retreat to the north this evening into Friday morning, with improvements in air quality from south to north with time,” the agency said in a news release. “On Friday, an area of low pressure moves through the region and further improves air quality for all but northeastern Minnesota.”
In New York, local officials urged residents to limit outdoor time and cautioned older adults, pregnant people and people with other risk factors, such as heart and lung disease, to remain inside. The city was handing out free KN95 face masks at hundreds of libraries, police precincts and firehouses, Mayor Zohran Mamdani said.
Canada, Minnesota wildfires driving smoke
Many of the fires affecting U.S. air quality are burning in parts of Canada, while additional wildfires in northern Minnesota near the Canadian border have contributed to smoke moving across the Upper Midwest and Great Lakes.
Nearly 900 wildfires are burning across Canada, with over 200 considered out of control, according to data from the Canadian Wildland Fire Information System. Most of the fires were in the central provinces of Manitoba, Ontario and Saskatchewan.
Multiple fires remained active in Minnesota, including six large fires that have scorched more than 41,000 acres as of July 16, according to the National Interagency Fire Center. The Minnesota Incident Command System (MNICS) said there were 15 active wildfires in the Superior National Forest, with 3 fires inside the Boundary Waters Canoe Area Wilderness.
Health concerns amid unhealthy air quality levels
Wildfire smoke, which can linger in the air for weeks, is more toxic than normal air pollution. PM2.5 can travel hundreds of miles and penetrate deep into the lungs.
Public health authorities continue to advise residents in affected areas to reduce strenuous outdoor activity, spend more time indoors, and monitor local air quality reports. In some locations, smoke concentrations have reached levels considered unhealthy for sensitive groups and, at times, unhealthy for the general public.
Health experts recommend keeping windows closed, using high-efficiency HVAC or air purifier filters when available, and wearing a properly fitted N95 mask if outdoor exposure is unavoidable.
Track air quality in your area
See the live map below to track air quality in your area. Green indicates good air quality, while yellow is moderate and orange is unhealthy for sensitive groups.
US air quality map
Contributing: Gabe Hauari, Ramon Padilla and Brandi D. Addison, USA TODAY; Reuters