St. Paul, Minn. – Unhealthy air is settling over parts of the Midwest and Ohio Valley this weekend as smoke from hundreds of Canadian wildfires drifts into the United States.
According to FireSmoke Canada and the Minnesota Pollution Control Agency, fine particulate pollution from over 1,500 active wildfires in Canada began impacting Minnesota on May 29. Poor air quality is expected to spread into upper Wisconsin and Michigan’s Upper Peninsula by Thursday evening, reaching the Ohio Valley by Friday and the Carolinas early Saturday.
Residents in impacted areas—including Louisville, Cincinnati, and Cleveland—should limit outdoor activity, especially those with heart or lung conditions. Health officials warn symptoms can include wheezing, chest pain, and increased risk of heart attack or stroke.
In 2023, Canadian wildfires scorched more than 37 million acres and caused widespread air quality issues across the U.S., a trend reflected in the American Lung Association’s 2025 report showing increased exposure to particle pollution nationwide.
The smoke is expected to linger through Sunday. Authorities urge residents to monitor local air quality indices and use air purifiers or wear N95 masks if necessary. Additional air quality alerts may be issued as conditions evolve.
