Wildfires in the Prairies having impact on air quality in several provinces

MONTREAL – Poor air quality fuelled by wildfires burning across the Prairies left a large swath of the country enveloped in a haze again on Saturday, but Environment Canada said the situation is expected to improve over the weekend.

Parts of Alberta, British Columbia, Manitoba, New Brunswick, Ontario, Quebec, Saskatchewan, and Newfoundland and Labrador were experiencing poor air quality and reduced visibility due to the wildfires, a situation expected to continue through Sunday.

Environment Canada meteorologist Jean-Philippe Bégin said there’s some good news — a low pressure system passing through the Prairies, currently in northern Saskatchewan and expected to move into Manitoba and northwestern Ontario by Monday, is expected to bring precipitation for areas hit by out-of-control forest fires.

That system is not expected to bring much relief in northern Alberta, however, where there is little rain in the forecast.

On Saturday, the agency’s air quality index listed some cities like Toronto and Montreal as having a moderate to high risk. The index measures air quality in relation to quality of health and rates it between one and 10.

Much of Ontario remained under special air quality statements or warnings on Saturday. Southern Ontario, which had been under an air quality statement on Thursday and Friday, saw that lifted early Saturday morning.

For Quebec, a weak cold front should help matters in eastern Quebec, including the province’s North Shore. The situation should improve into Sunday in Montreal and in southern Quebec.

A high concentration of fine particles in the air can be harmful to health and the air quality situation is far worse in areas where fires are burning, Bégin said. 

“In no region of Quebec do we have concentrations above 100 micrograms per cubic metre,” Bégin said. 

“Near the fires in northwestern Ontario, northern Manitoba, northern Saskatchewan, northern Alberta, we have in some places, definitely more than 100 micrograms per cubic metre and we have up to 600 micrograms per cubic metre, so the air quality is quite dangerous there.”

In Montreal, public health officials were advising residents to keep windows closed, reduce outdoor activities and limit non-essential travel. 

While the entire population is affected by air quality, the most vulnerable include children under the age of five, pregnant women, the elderly and anyone suffering from heart or respiratory issues.

This report by The Canadian Press was first published June 7, 2025.

— with files from Coralie Laplante in Montreal and Rianna Lim in Toronto.