Toronto records highest global air-quality index as wildfire smoke spreads to US
Smoke from wildfires in northwestern Ontario has pushed Toronto's air quality to the worst level worldwide, prompting health alerts in Canada and several US states.
Smoke from a series of wildfires in northwestern Ontario has driven Toronto's Air Quality Health Index above 10, a level classified as "very high risk," and placed the city at the top of a global ranking of poor air quality. The Swiss firm IQAir said Toronto now ranks lower than Kinshasa and New Delhi, attributing the spike primarily to wildfire emissions and unusually warm temperatures. > "The biggest contributor to Toronto’s spike in air pollution right now is wildfires, though the higher-than-average temperatures are also playing a role," Armen Araradian of IQAir told AFP.
Environment Canada warned that hazardous conditions could continue through Thursday night. More than 800 fires are active across Canada, with about 112 out of control, mainly in Manitoba, Saskatchewan and Ontario, having burned roughly 1.9 million hectares so far. The Canadian government noted that the current season started slower than the severe years of 2023 and 2025 but emphasized that warmer temperatures increase fire risk.
The smoke has crossed the border, affecting air quality in Pennsylvania, New York, Connecticut, Massachusetts, Maine and New Hampshire. New York City officials issued an unhealthy-air alert, advising residents to limit strenuous outdoor activity. > "We probably haven’t seen the worst of it yet for New York City. We probably haven’t seen the worst of it yet for the Great Lakes and upstate, and New England yet either," Dan Westervelt, a Columbia University researcher, told Reuters.
Governor Kathy Hochul urged people, especially those with health conditions, to take precautions. The haze is expected to linger through the end of the week, according to the National Weather Service. Anticipated crowds for the upcoming FIFA World Cup final in New Jersey and viewing events in Central Park may face reduced visibility.
University of Toronto professor Greg Evans said the combination of heat and smoke is likely to become more common, stressing the need for cities and residents to prepare for future events.