Wildfire Smoke Causes Poor Air Quality in Canada and U.S. States

Toronto, Canada — As of July 14, 2025, wildfire smoke has led to poor air quality across many U.S. states and Canadian provinces, particularly in the Great Lakes region. The air quality index ranges from “moderate” to poor in much of Michigan, Minnesota, and Wisconsin, with additional impacts felt in parts of Illinois, Indiana, Iowa, Ohio, and New York.

In Canada, major cities such as Toronto and those across Ontario and Quebec are experiencing unhealthy air conditions. As of the morning of July 14, Toronto was ranked as the third most polluted major city globally, while Chicago stood at 11th, according to data from IQAir.

Widespread wildfires in northern Canada, coupled with changing wind conditions, have pushed smoke southeastward, affecting the Great Lakes Region and the St. Lawrence River. The National Weather Service has issued air quality alerts for all of Michigan and Wisconsin, as well as parts of western New York, northern Minnesota, and northeastern Indiana. Toronto’s air quality warning extends throughout central Ontario.

Environment Canada has also issued a special air quality statement for the Greater Toronto Area, warning that smoke from forest fires in northern Ontario and the Prairies is expected to degrade air quality and visibility. They recommend limiting outdoor activities, especially for vulnerable populations.

Monday’s heat wave complicates conditions, with daytime temperatures predicted to reach between 31 and 35 degrees Celsius, feeling even hotter with humidity. Overnight lows offer little relief. Environment Canada urges residents to stay hydrated and check on those at higher risk for heat-related illnesses.

Dr. Christopher Labos, a cardiologist, explains that both heat and poor air quality can strain the body. “While you wait for medical attention, it’s important to try to cool a person down by moving them to a cooler place and hydrating often,” he advised. He also cautions pet owners, noting that pets can be just as vulnerable to heat and smoke.

The ongoing situation underscores the expected increase in extreme weather events and their impact on public health due to climate change.