Toronto woke up to a thick haze on Monday morning as wildfire smoke from northern Ontario swept into the region, drastically reducing visibility and pushing pollution levels to dangerous highs.
Environment and Climate Change Canada (ECCC) issued an official air quality warning for Toronto early Monday, citing alarmingly high levels of particulate matter in the air.
Upper-level winds are continuing to push thick plumes of smoke from active wildfires across the region, creating dangerous breathing conditions that could persist through midweek. The federal agency warned that poor air quality could continue into Tuesday or even later in some areas.
Smoke mixing down to the surface is causing a spike in fine particulate matter (PM2.5), a major contributor to health risks.
As of 8 a.m. Monday morning, Toronto ranked as the world’s second most polluted major city, according to IQAir, a global air quality monitoring agency. The city’s Air Quality Health Index (AQHI) reached a high-risk level of 10, posing health risks for all residents, especially vulnerable groups like seniors, children, and those with pre-existing respiratory conditions.
The ongoing wildfires in northwestern Ontario, Manitoba, and Saskatchewan have burned more than 5 million hectares in 2025 alone, doubling the five-year average for this time of year. This marks the second time this summer that Toronto has experienced such high risk levels of air quality from the fires.
The ECCC is urging residents to take precautions, including staying indoors when possible with the windows closed, using air purifiers or HEPA filters if available, and if you’re working outdoors, it is strongly encouraged to wear a high-quality respirator mask, such as an N95 or KN95, to reduce exposure to harmful pollutants.