Millions warned as wildfire smoke returns to Ontario skies
Air quality warnings in effect for the Greater Toronto Area, as wildfire smoke from northern Ontario impacts much of the province. The poor air quality may persist for the next several days for some areas
Expect deteriorating air quality across parts of Ontario as we start this new workweek, as upper-level winds blow wildfire smoke into the region.
Some of the smoke could mix down to the surface, lowering air quality from northern Ontario to the Greater Toronto Area (GTA). An air quality warning was issued for Toronto and much of the GTA first thing Monday, with widespread special air quality statements covering a lot of the province. As of 8 a.m. Monday, Toronto actually ranked as the world's second-most polluted major city, according to IQAir, a Swiss-based air quality technology firm.
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The poor air quality may persist into Tuesday for some areas. Folks whose respiratory systems are especially sensitive to wildfire smoke should use extra caution over the next couple of days.
Shifting winds blow smoke into Ontario
It’s already been a rough year for wildfires across Canada. The total area burned since January 1, 2025, has surpassed 5 million hectares, with over 3,000 fires reported so far this year. For reference, the five-year average for this time of year is just 2.5 million hectares.
Active blazes over Saskatchewan, Manitoba, and northwestern Ontario have sent prolific plumes of smoke billowing into the atmosphere. Westerly upper-level winds blowing across these wildfire zones will force smoke to move over Ontario through the upcoming week.
Many communities across Ontario already reported reduced air quality on Sunday evening. Tiverton, Sault Ste. Marie, and North Bay all saw high risk air quality levels, while Barrie and Grand Bend reported air quality at the moderate risk level.
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Sinking air behind the frontal system responsible for this weekend’s potent thunderstorms will allow the smoke to mix directly down to the surface, further affecting air quality over the next couple of days.
The air quality health index rating was already sitting at a "high" risk of 10 across much of the GTA Monday morning. The risk is likely to hover around 6 in the city of Toronto through Tuesday.
Models indicate that the smoke could linger across the province until at least Wednesday, possibly extending into Thursday.
Wildfire smoke can cause respiratory problems in those who suffer from chronic illnesses or respiratory diseases. If possible, stay indoors during periods of reduced air quality, and consider wearing a mask outdoors to reduce your exposure to fine particulate matter.