Dangerous Air Quality Persists Across Ontario Amid Widespread Wildfire Smoke

A woman bikes along the waterfront in Toronto as wildfire smoke fills the city, on July 15, 2026. The Canadian Press/Laura Proctor

Ontario will continue to experience some of the world’s most hazardous air quality today as wildfire smoke covers much of the province.

Environment Canada has issued an air quality warning for much of central and southern Ontario as smoke from wildfires raging in the province’s northwest cause another day of poor air quality and heightened health risks.

Environment Canada issued its highest warning early on July 16—10+ or very high risk—for the Greater Toronto Area and several other large urban centres, including Kitchener, London, Hamilton, Windsor, and Sarnia.

Areas as far east as Belleville and as far north as Sault Ste. Marie and North Bay were under the same 10+ air advisory.

“During heavy smoke conditions, everyone’s health is at risk regardless of their age or health status,” the agency said in an advisory. “Limit time outdoors. Reschedule or cancel outdoor sports, activities and events.”

A change in wind direction from northwest to northeast has brought better air quality to some sections of eastern Ontario. Kingston was classified as a six or moderate risk by Environment Canada during the early morning hours and Ottawa was a three, or low risk.

Toronto

Toronto ranked first globally for poor air quality on July 15 as conditions worsened throughout the day.

As of 10 a.m. on July 16, the city was in second place on the most polluted air list by IQAir, a Swiss air quality technology company that operates the world’s largest real-time air quality information platform.

IQAir uses the US EPA scale, which categorizes any reading above 300 as “hazardous” and indicates an emergency-level pollution event that carries serious health threats for everyone, regardless of their health status. Toronto had an air quality score of 400.

The City of Toronto advised residents in a social media post to stay indoors as much as possible to minimize health risks and noted it would adjust several of its services due to the smokey air.

All outdoor swimming and wading pools that were closed on July 15 will remain closed, city daycares and CampTO programs will operate indoors only, and all outdoor registered programming will be cancelled, postponed, or moved indoors “where possible,” the city said.

Air Quality

Air Quality Ontario measured downtown Toronto’s air at a particulate matter rating of 244 as of 9 a.m., indicating a high concentration of microscopic airborne particles that pose significant respiratory and cardiovascular risks.

This is more than 14 times the World Health Organization’s 24-hour guideline of 15 micrograms per cubic metre.

Toronto wasn’t the worst on the provincial list, however.

Some areas of Windsor had a particulate matter rating of 434 and Thunder Bay, which is close to the wildfires in the northern part of the province had a rating of 443.

An air quality index rating of 443 is an off-the-charts emergency that exceeds all health thresholds set by the World Health Organization (WHO) and is 30 times higher than the WHO’s absolute safe 24-hour limit.

Environment Canada is recommending anyone forced to spend time outside wear a “well-constructed, well-fitting and properly worn respirator type mask,” but warns that even a mask won’t eliminate health risks.

People 65 or older, pregnant women, infants and young children, those with pre-existing illnesses or chronic health conditions, and outdoor workers are more susceptible to the effects of wildfire smoke, the agency said.

Common symptoms of smoke exposure include eye, nose and throat irritation, headaches, and a mild cough.

“More serious but less common symptoms include wheezing, chest pains or severe cough,” Environment Canada said. “If you think you are having a medical emergency, seek immediate medical assistance.”