Toronto air quality turns hazardous as wildfire smoke spreads south

Toronto’s air quality hit hazardous levels Thursday morning as wildfire smoke from northwestern Ontario blanketed the city and turned the sky orange. The city ranked among the worst major urban air readings in the world on July 15 and July 16.

The smoke plume was tied to major fires burning in west-central and northwestern Ontario, where conditions remained severe enough to keep the haze moving across provincial and national borders. More than 830 wildfires were burning across Canada on Wednesday, while more than a dozen fires were active in northern Minnesota. Smoke drifted east across the Great Lakes and into the U.S. Northeast, with air quality alerts issued in several places along the route.

Environment Canada warned of poor air quality in Toronto because of wildfire smoke, and the federal government’s Air Quality Health Index tracked observed conditions across the city and the province. The AQHI is the main public gauge residents should watch over the next 24 hours, especially as the smoke shifts with changing wind patterns and can intensify quickly in some neighborhoods while easing in others.

Cut time outdoors, avoid strenuous activity outside, and keep windows and doors closed as much as possible. In places where heat is also a factor, officials have urged people to prioritize staying cool while smoke lingers indoors and outdoors. New York City Emergency Management extended its heat emergency plan into Thursday, July 16. Air quality was forecast to reach unhealthy levels as Canadian wildfire smoke moved into the region, and cooling centers remained open.