Canadian wildfire smoke chokes US Midwest and East Coast, triggering hazardous air alerts

Smoke blankets major US cities

Thick smoke from hundreds of wildfires in Canada has shrouded a swath of the United States from the Great Lakes to the East Coast. Chicago recorded a PM2.5 level of 669 on Thursday, making it the most polluted major city in the world according to IQAir. By Friday, Detroit and Chicago both registered air quality index readings in the hazardous range, while New York City was deemed unhealthy for sensitive groups. The National Weather Service warned that conditions could worsen overnight into Saturday as winds over the Great Lakes push more smoke into the Northeast.

Wind over the Great Lakes region could cause more smoke to pour into the Northeast, which could keep skies hazy.

Health warnings and disruptions

The hazardous air has triggered widespread precautions. Emergency room visits for asthma are expected to spike by 50 percent or more, and breathing the air in affected cities has been compared to smoking a pack of cigarettes a day. Restaurants closed patios, day camps shut down, outdoor concerts were canceled, and festivals scaled back. Indoor spaces felt the strain too, with HVAC units working overtime to filter particles while coping with extreme heat, risking damage from clogged filters and spiking energy consumption.

These are compound events, and that can sometimes make the impacts of them far worse than what we would experience with any one of these events individually.

Extreme weather across the US

The smoke is part of a broader pattern of extreme weather. While the East choked on smoke, Texas's Hill Country endured its third consecutive day of severe flooding. In the West, 68 large wildfires were active across 15 states, with 17 new blazes erupting in the Pacific Northwest overnight after lightning strikes. Over 17,400 personnel, 140 helicopters, and four military C-130 air tanker crews are battling the fires. Nearly 3.72 million acres have burned in the US so far this year, surpassing last year's mid-July total by more than a million acres.

Human-driven climate change has led to a tripling of these stalled jet stream events since the 1950s.

Climate change driving more frequent smoke events

The orange skies of 2023, 2025, and now 2026 are no longer rare. Research shows per-person exposure to harmful wildfire smoke in the US was four times higher during 2020–2024 than in 2006–2019. A Nature study projects that wildfire smoke will cause 71,420 excess deaths annually in the US by mid-century, a 73 percent increase compared to the 2010s, with up to 1.9 million smoke-related deaths between now and then. In Canada, 2.784 million hectares (6.8 million acres) have burned, and Prime Minister Mark Carney said the situation has escalated significantly over the last three weeks, forcing thousands to evacuate.

World Cup final under watch

FIFA World Cup organizers are monitoring air quality closely ahead of the final between Spain and Argentina at New York New Jersey Stadium. A National Weather Service liaison is embedded at FIFA headquarters.

There's been discussion about it, and we have somebody with the National Weather Service that sits in FIFA headquarters there, so we're monitoring closely.