Wildfire smoke from Canada is shrouding the Northeast and the Midwest, harming the air quality during a summer heat wave.

Winds swept smoke from the north, where the Canadian government reported more than 100 uncontrolled wildfires. Swaths of the Northeast and Midwest were under air quality alerts that might continue into Thursday, according to the National Weather Service.

"Expect we'll once again see widespread reduced visibility, perhaps even lower than what we're seeing so far," the National Weather Service said.

Forecasters said the densest plume of smoke should move south over the Mid-Atlantic, and more fumes could appear Thursday night. The hazy air could clear up by Friday, meteorologists said, but it was too early to determine the weekend outlook. New Jersey is preparing to host the World Cup final on Sunday in an outdoor stadium.

Smoky conditions were set to worsen on Thursday and possibly Friday in Maryland, Washington, D.C., and Virginia, meteorologists said.

The smoke turned the skies gray in affected areas on Wednesday, compounding a heat wave. The air quality was unhealthy in parts of the Northeast and the Great Lakes, according to the Environmental Protection Agency. The EPA suggested people, especially children and the elderly, shorten how long they spend outside.

Authorities ordered evacuations in parts of northern Minnesota near a cluster of Canadian wildfires. New York City opened hundreds of cooling centers and was distributing masks to curb smoke inhalation.

The EPA said the biggest health threat from smoke is fine particles that can be inhaled or enter people's eyes. The particles can cause burning eyes or runny noses. Healthy people aren't usually at a major risk from short-term exposure to smoke, the EPA said.

Write to Alyssa Lukpat at alyssa.lukpat@wsj.com

(END) Dow Jones Newswires

July 15, 2026 22:13 ET (02:13 GMT)

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