Toronto is waking up under a thick blanket of wildfire smoke, and the city has earned a title no one wants. According to air quality monitoring platform IQAir, Toronto is currently experiencing the worst air quality of any major city in the world, temporarily surpassing cities that frequently struggle with severe pollution, including Delhi and Kinshasa.
The dramatic decline in air quality comes as smoke from large wildfires burning across northwestern Ontario drifts south, while an intense summer heatwave continues to grip southern Ontario.
The combination of soaring temperatures and stagnant weather conditions has created the perfect environment for smoke to linger over the Greater Toronto Area. A stubborn high-pressure system, often referred to as a heat dome, has triggered what’s known as an atmospheric inversion, where a layer of warm air traps cooler air and pollutants near the ground instead of allowing them to disperse.
As a result, fine particulate matter, known as PM2.5, has accumulated across the region, creating hazy skies and significantly reducing air quality.
Environment and Climate Change Canada has issued a special Air Quality Health Index warning, with conditions reaching Level 8, classified as “High Risk,” and expected to worsen to Level 10+, or “Very High Risk.”
Health officials say everyone should limit prolonged outdoor activity, but the greatest concern is for seniors, young children, pregnant people, individuals with underlying health conditions, and anyone working outdoors, who are advised to avoid strenuous activity outside whenever possible.
Forecasters say the smoky conditions are expected to persist until changing winds push the haze out of the region. Conditions across southern Ontario are expected to improve on Friday. Until then, residents are encouraged to stay indoors whenever possible, avoid unnecessary outdoor exertion, and take steps to keep indoor air as clean as they can.
