Toronto engulfed by wildfire smoke as US cities threatened

Wildfire smoke from northwestern Ontario has engulfed Toronto, creating hazardous air quality conditions that have spread across the northeastern United States. Environment Canada recorded an Air Quality Health Index reading of 10+ for Toronto, classified as "very high risk," with forecasts indicating that dangerous conditions would persist through Thursday night. IQAir, a Swiss air quality technology company, ranked Toronto as having the worst air quality among all major global cities, surpassing the Democratic Republic of the Congo's Kinshasa and India's New Delhi.

Canada is currently managing more than 800 active wildfires nationwide, though this year's wildfire season has been relatively moderate compared with recent years. Wildfires continue burning through sparsely populated areas hundreds of miles from Toronto, with smoke dispersing across a wide geographic area. A viral video captured a Canadian National train surrounded by flames near Armstrong, Ontario, prompting the railroad operator to evacuate employees and residents on Monday night and suspend rail operations in the area as a precautionary measure.

The smoke has significantly degraded air quality across the US border, with Pennsylvania, New York, Connecticut, Massachusetts, Maine, and New Hampshire experiencing particularly severe impacts. New York City authorities issued health alerts urging residents to limit strenuous outdoor activity and take frequent breaks if spending time outside. The National Weather Service projected that smoke could linger through the end of the week. Columbia University researcher Dan Westervelt cautioned that New York City and the Great Lakes region had likely not yet experienced the worst air quality conditions. The deteriorating conditions pose concerns for major outdoor events, including the FIFA World Cup final scheduled for Sunday at an open-air stadium in New Jersey, expected to draw over 80,000 attendees, with another 50,000 planning to watch from New York City's Central Park.