Forest fire smoke prompts air quality warning for Toronto

People take in a city view of Toronto on Monday July 14, 2025. The Air Quality Health Index rating for Toronto was over 10, or "very high risk,"from wildfire smoke on Monday morning. THE CANADIAN PRESS/Chris Young

Environment Canada has issued a Special Air Quality Statement for Toronto, warning that drifting wildfire smoke is expected to cause poor air quality and reduced visibility throughout the day.

The agency says the forest-fire smoke affecting much of southern Ontario may persist into Monday, in some areas.

“Air quality and visibility due to wildfire smoke can fluctuate over short distances and can vary considerably from hour to hour,” the agency said.

Officials are urging residents to limit outdoor activities and stay indoors as much as possible, especially vulnerable people such as seniors, young children, people with health conditions, and those who work outdoors.

It’s advised that common symptoms of smoke exposure can include throat irritation, coughing, and headaches, while more severe reactions can include wheezing and chest pain.

Anyone experiencing a medical emergency is asked to seek help immediately.

Environment Canada recommends keeping windows and doors closed and using clean air filters or certified air purifiers indoors.

“If you must spend time outdoors, a well-constructed, well-fitting and properly worn respirator type mask (such as a NIOSH-certified N95 or equivalent respirator) can reduce your exposure to the fine particles in the smoke,” the statement read.

Air quality expert urging people to stay indoors during smoky conditions

Speaking with CP24’s Sijia Liu late Sunday afternoon, air quality expert Jed Kaplan said the forest fires across the country, especially in Manitoba and northern Saskatchewan, have been so hot that the smoke they’ve generated has gone quite high up in the sky, adding that those particles have the ability to travel thousands of kilometres in the upper levels of the atmosphere.

Measuring less than a quarter of a millimetre in size, Kaplan explained that they can penetrate “really deep” into the lungs and exacerbate health risks for people who have respiratory illness or heart disease, as well as the elderly and young children.

“It’s especially bad to be outside under those kinds of smoky conditions,” he said, adding that many of the wildfires seen across Canada have been burning since the fire season began at the start of May.

Kaplan said while it’s not ideal to stay indoors over the long weekend, it’s a good idea to do so, especially for those who are significantly negatively affected by forest fire smoke.

“If you’ve got air con or if you have an air purifier be using it for sure. If you don’t have a purifier, consider going to the library or the mall, any place that’s considered going to likely to have clear hair,” he said.

“And if you do need to be outside, hate to say it, but it’s probably a good idea to wear a tight fitting N95 mask, because that’s going to be the thing that will protect you the most from the tiny wildfire smoke particles.”

Depending on the winds and when it rains, certain regions, like southern Ontario and the Greater Toronto Area, may experience several periods of poor air quality, Kaplan said.

“Basically, it’s going to probably last like that until the end of summer, maybe September or October, until the snow starts up falling and those fires start to die down,” said Kaplan, noting that with climate change, notably “intense warming in the north,” the annual fire season will likely get “longer and longer.”