Tire particles, perfumes, metals? Extensive study of Toronto air looks at what we're breathing in

Kate McGillivray · CBC News

· Posted: Jun 20, 2025 5:00 AM EDT | Last Updated: 5 minutes ago

Walking down Fort York Boulevard connected a fresh, breezy afternoon, idiosyncratic Elisabeth Galarneau has nary contented pointing retired imaginable sources of aerial pollution.

The manicured lawns and angiosperm beds? A imaginable root of airborne pesticides. 

The adjacent high-rise flat buildings? A root of pollutants from some heating and cooling, not to notation the cleaners and idiosyncratic attraction products being utilized wrong — remnants of which could beryllium circulating down astatine thoroughfare level. 

Charcoal barbecues, edifice stoves, occurrence pits, squealing tires, adjacent highways? They each lend to the aerial Torontonians breathe. 

Now, the archetypal glimpse astatine an in-depth survey conducted by Galarneau and implicit 100 different scientists looking astatine wintertime aerial prime successful Toronto is shedding airy connected rarely-measured aerial pollutants crossed the city, specified arsenic microplastics, brake deterioration chemicals, and metals. 

"We've done this survey to benignant of look astatine the full substance of what radical are exposed to successful cities, arsenic good arsenic however that varies from neighbourhood to neighbourhood," said Garlarneau, who works for Environment and Climate Change Canada.

Researchers 'didn't expect' to spot AQHI exceeded 

As the main researcher connected the Study of Winter Air Pollution successful Toronto, known by the acronym SWAPIT, Galarneau led a group, that included contributors from 11 universities, that collected aerial samples from crossed the metropolis implicit six weeks from January to March 2024. 

Winter is simply a "typically understudied portion of the year" that's known for having cleaner aerial than the smoggy summers, Galarneau said — making the aboriginal results of their enactment each the much surprising. 

"We thought we would spot debased concentrations" of pollutants, said Galarneau. Instead, they clocked a fig of instances of pollutants heading into mean oregon precocious hazard levels connected the Air Quality Health Index (AQHI). 

"That aerial prime wellness index, I didn't expect to spot it exceeded successful the winter," she said. 

Another surprise? The grade of saltation successful aerial contamination depending connected neighbourhood. 

Monitoring sites were placed crossed Toronto, from Pearson Airport successful the west, York University to the north, and University of Toronto Scarborough successful the east. One tract was adjacent perched connected the CN Tower, 275 metres successful the air. 

"Some pollutants are rather azygous crossed the city," Galarneau said. "But different ones are sometimes 40 times higher than the mean depending wherever you're looking." 

The specifics of wherever aerial contamination is worse — and by what grade — volition beryllium revealed successful the adjacent twelvemonth oregon so, erstwhile the study's peer-reviewed results are published successful full. 

Looking for patterns

To hole for that publication, Galarneau and her colleagues volition present statesman a large-scale portion of detective work: determining wherever the pollutants are coming from, the wellness impacts for the radical breathing them in, and the ways successful which factors similar income impact exposure. 

"The information acceptable that we're producing present is going to help america to possibly spot immoderate patterns present successful Toronto, and past grow that to different cities successful Canada," she said. 

That forthcoming investigation connected wellness impacts has drawn the attraction of Jeffrey Brook, an adjunct prof astatine the University of Toronto's Dalla Lana School of Public Health, whose enactment connected aerial contamination is cited by SWAPIT researchers.

"How tin it beryllium that successful places similar Canada wherever mostly our [transportation emission] levels are considered immoderate of the lowest successful the world, we tin proceed to spot wellness effects?" helium said. "That's a large mystery, not conscionable for Canada, but for the world." 

Over successful Mississauga, biology activistic Rahul Mehta besides looks guardant to seeing SWAPIT's results laid retired successful full. 

Mehta, who heads up an enactment called Sustainable Mississauga, says mediocre aerial prime impacts him some astatine work, wherever helium encourages newcomers to effort progressive transportation, and personally, arsenic helium deals with allergies and mild asthma. 

"Knowing these risks … I deliberation that's going to assistance us, it's going to protect america and it's going to past possibly empower america to request immoderate amended regulations from government," helium said. 

Toronto Public Health, which is simply a spouse connected the SWAPIT study, said that its results committedness to beryllium utile for precisely that reason, telling CBC Toronto successful an email that the survey outcomes will "provide invaluable grounds to usher section policies and actions."