Air quality in Toronto among worst in world amid wildfire smoke, global tracker shows

Toronto was the fourth-most polluted major city in the world on Friday night as wildfire smoke hung over the city, according to a global tracker.

The ranking by IQAir, a Swiss air quality technology company, placed the city below Detroit, U.S., Delhi, India, and Montreal, which remained in third place on Friday night as it also faces wildfire smoke from western provinces. 

As of 9 p.m. Friday, air quality in Toronto was at seven on Environment Canada's air quality health index, according to the weather agency's website. A value between four to six is considered moderate risk, while seven to 10 is high risk, the agency's website reads. 

Parts of the Greater Toronto Area and surrounding communities were under a special air quality statement on Friday as wildfires continued to scorch Manitoba, Saskatchewan and Alberta. 

Wildfire smoke is causing or expected to cause poor air quality and reduced visibility, Environment Canada said in a statement on Friday. Poor air quality was expected to persist into the evening Friday.

The air quality statement was in effect for the following areas: Toronto, Mississauga, Brampton, Vaughan, Richmond Hill, Markham, Durham Region, Pickering, Oshawa, Uxbridge, Beaverton, Halton Hills, Milton, Oakville, Newmarket and Georgina.

Environment Canada issued a similar special air quality statement for much of Ontario on Thursday. 

People are advised to limit time outdoors and consider reducing or rescheduling outdoor activities or events, the federal weather agency said in Friday's statement. 

Those who must spend time outdoors are advised to wear a "well-constructed, well-fitting and properly worn respirator type mask" such as an N95 mask, Environment Canada said. 

These masks can reduce exposure to fine particles in the smoke, but there can still be risks to health, the statement read. 

When indoors, people are advised to keep windows and doors closed as much as possible. A clean, good quality air filter in your ventilation system or a certified portable air cleaner may help protect indoor air from wildfire smoke, Environment Canada said. 

People may experience "mild and common symptoms" such as eye, nose and throat irritation, headaches or a mild cough, the federal weather agency said. 

More serious and less common symptoms include wheezing, chest pains or severe cough. People are advised to seek immediate medical assistance if they think they are having a medical emergency. 

Seniors, pregnant people, infants, young children, people with existing illness or chronic health conditions, and those who work outdoors are the most likely to be impacted by outdoor health pollution, Environment Canada said. 

"Check in on others who are in your care or live nearby who may be more likely to be impacted by outdoor air pollution," the statement read.

Toronto Pearson International Airport said it did not "anticipate any impacts to operations" as a result of the smoke, in a post on X on Friday.