Air quality still a major concern across Ontario heading into the weekend
Poor air quality persists across much of Ontario due to wildfire smoke, with limited improvement expected as shifting winds and ongoing fires keep AQHI levels high into the weekend
The air quality health index (AQHI) remains high to very high across much of Ontario as of Friday, with health officials advising residents to minimize time outdoors.
Wildfire activity in northwestern Ontario has led to evacuation orders and has sent thick smoke sweeping across the region and downwind into parts of the province.
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Another smoky day on Friday
Although minor improvements were observed over the last 24 hours in southern Ontario, conditions deteriorated again Friday morning.
AQHI readings across the Greater Toronto Area (GTA), southwestern Ontario, and northern areas are at 10+, marking the highest risk level on the index. Readings of 7 or higher trigger air quality warnings, with health officials urging individuals, particularly those with health concerns, to limit exposure and consider wearing approved masks when outdoors.
A wind shift since Thursday has brought some relief to eastern Ontario, where AQHI readings have dropped below warning levels. However, the heaviest smoke is now concentrated over southwestern Ontario.
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Looking ahead, winds may push smoke into eastern Ontario and the Ottawa Valley on Saturday, raising AQHI levels to moderate or high. The GTA and southwestern Ontario are likely to see persistent poor air quality into the weekend.
Will the rain actually help?
Rain and thunderstorms over the last 12–18 hours have offered modest relief to areas of northwestern Ontario.
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However, lightning poses the risk of further fire starts, while prevailing poor weather conditions continue to sustain wildfire activity and dense smoke production.
WATCH: Rain relief begins in Thunder Bay
For southern Ontario, a trough moving through Friday evening into Saturday brings the potential for showers and thunderstorms. However, the persistence of smoke could limit precipitation in some areas.
Uncertainty remains regarding improvements in southwestern Ontario, as wildfire growth and shifting winds may prolong poor air quality conditions into the weekend. Several days of significant rainfall and higher humidity are needed to make a substantial impact.
Health and visibility impacts:
Smoke at low atmospheric levels raises health risks
Increased discomfort for individuals with respiratory conditions
Hazy skies and the smell of campfire
Red sunrises and sunsets
DON'T MISS: The Weather Network's hub for all wildfire information in Canada
Limiting outdoor activity is advised in affected areas.