CNN
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Major US cities trapped under a thick, orange blanket of smog this week will soon get a reprieve, as the Canadian wildfires spewing noxious fumes across the border are easing up.
Fire activity in the province of Quebec has improved, and the area covered by smoke is now just 7% of what it was last week. Slightly cooler temperatures and higher humidity in Canada mean less smoke billowing across the border.
But there are two big caveats: It’s still early in the Canadian fire season, meaning more wildfires could flare up this summer. And several US states are still suffering poor air quality, which could cause health problems.
“Smoke from Canadian wildfires continues to be transported south by winds into the U.S. resulting in moderate to unhealthy air quality across parts of the Northeast, mid-Atlantic, Ohio Valley, and Midwest on Friday,” the National Weather Service said. “Some improvement is expected this weekend.”
While the worst has passed for most of the Northeast and mid-Atlantic regions, potentially harmful air pollutants in New York City, Philadelphia and Washington, DC, are expected to linger Friday before slowly clearing over the next several days.
Philadelphia’s air quality index exceeded 150 early Friday, making it “unhealthy,” according to the monitoring website AirNow. New York City’s air quality index was below 150 early Friday and deemed “unhealthy for sensitive groups.”
The oppressive smoke this week has postponed professional sports games, grounded flights due to poor visibility, shuttered zoos and beaches and forced many to mask up outdoors. Climate experts have warned such events are becoming more frequent due to human-induced climate change.
About 50 million people across several Midwest and East Coast states were under air quality alerts early Friday, but the number could change as conditions improve in some areas.
Here’s what to expect:
• Entire states’ air quality is compromised: All of Pennsylvania, Delaware, Connecticut, Rhode Island, New Jersey and Indiana are under air quality alerts, as well as parts of Ohio, Michigan, Maryland, Virginia and North Carolina.
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The US Capitol in Washington, DC, was shrouded in smoke Thursday.
• Schools go remote: Public schools in New York City, Philadelphia and Washington, DC, have remote learning Friday to help reduce exposure to air toxins.
• New York City will improve: After having the world’s worst air quality multiple times this week, according to IQAir, the Big Apple could see some “significant improvement,” Mayor Eric Adams said Thursday. “As of right now, the smoke models are not indicating another large plume over the city,” Adams said, though he urged people to mask well when outside.
• Evacuated Canadians can go home: Most of the Halifax residents evacuated because of the wildfires will be allowed to return home Friday, Mayor Mike Savage said. About 16,000 people fled their homes during the height of the wildfire evacuations, and about 4,100 remain evacuated.
• Firefighters will get help: New York state plans to send forest rangers to help fight the wildfires in Quebec Friday, Gov. Kathy Hochul said. Federal resources have also been deployed, the White House has said.
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People look out at a hazy Manhattan skyline from the Rockefeller Center viewing deck Friday, June 30, in New York.
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Smoke from wildfires in Canada shrouds the view of the Statue of Liberty on Friday in New York.
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The setting sun is shrouded by smoke from Canadian wildfires in this photo taken from New York's 42nd Street on Thursday, June 29.
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Haze hangs over downtown Pittsburgh and PNC Park as fans take their seats before a Major League Baseball game between the Pittsburgh Pirates and the San Diego Padres on June 29.
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Traffic makes its way across the Chesapeake Bay Bridge in Stevensville, Maryland, on June 29.
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Smoke and haze is seen from the Lincoln Memorial in Washington, DC, on Tuesday, June 27.
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People in Chicago walk along the shoreline of Lake Michigan on June 27.
Cpl Marc-Andre Leclerc/Canadian Forces/Reuters
A Canadian soldier flies over a wildfire near Mistissini, Quebec, on June 12.
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Wildfires burn in British Columbia in this aerial photo released by the BC Wildfire Service on June 9.
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A jogger wears a face mask in Washington, DC, on June 9.
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A man wears a protective face mask while walking through Times Square in New York on June 8.
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An airplane takes off June 8 from Ronald Reagan Washington National Airport in Arlington, Virginia.
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Traffic heads into Washington, DC, under hazy conditions on June 8.
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Smoke from Canadian wildfires obscures the visibility in Pittsburgh on June 8.
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Buildings in the Philadelphia skyline are shrouded in smoke on June 8.
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A cyclist rides under a blanket of haze that was partially obscuring the US Capitol on June 8.
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A woman in New York City wears a mask during the morning rush hour on June 8. The city saw slight air quality improvements, but levels were still considered "very unhealthy" for residents.
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The One World Trade Center tower is seen in New York, shortly after sunrise on June 8.
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A starting gate is unused at Belmont Park in Elmont, New York, on June 8.
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Transit employee Shanita Hancle, left, hands out masks to commuters at a subway station in New York on June 8.
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The Philadelphia skyline is shrouded in haze on June 8.
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A smoky haze obscures M&T Bank Stadium in Baltimore on June 8.
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Firefighters battle a wildfire in Evansburg, Alberta, on June 8.
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A person on the New York City subway wears a mask as smoky haze blankets a neighborhood on June 7.
Matt Slocum/AP
Workers chain up seats at Citizens Bank Park after the Philadelphia Phillies postponed a baseball game because of poor air quality on June 7. The New York Yankees also postponed a game that night.
Amr Alfiky/Reuters
Two men stand by the waterfront in Brooklyn, New York, on June 7.
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Smoky haze affects the visibility of the Empire State Building in New York on June 7.
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A man in Piermont, New York, attempts to photograph the sun obscured by smoke on June 7.
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Smoke blankets the Lincoln Memorial Reflecting Pool and the National Mall on June 7.
Seth Wenig/AP
A person in Fort Lee, New Jersey, talks on the phone near the George Washington Bridge on June 7.
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Smoke obscures the view from the New York State Thruway, looking north from West Nyack on June 7.
Yuki Iwamura/AP
People wear face masks as they walk in New York's Herald Square on June 7.
Mike Segar/Reuters
A woman jogs along the Hudson River as a smoky haze hangs over the New York City skyline shortly after sunrise on June 7.
Kareem Elgazzar/The Cincinnati Enquirer/USA Today Network
A couple sits for lunch in Cincinnati on June 6. Smoke from the Canadian wildfires had drifted to the city, causing the air to appear hazy.
Carlos Osorio/Reuters
People at Toronto's CN Tower take photos of the smoky city on June 6.
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The sky is discolored during a New York Yankees baseball game on June 6.
Merrily Cassidy/Cape Cod Times/USA Today Network
A smoky sky provides a muted backdrop June 6 at Rock Harbor in Massachusetts. Skies over Cape Cod were filled with smoke from the wildfires in Canada.
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People in New York wear masks as they ride bikes on June 6. That morning, the city briefly had the world's worst levels of air pollution.
Amr Alfiky/Reuters
The Statue of Liberty is obscured by the air pollution in New York on June 6.
Spencer Colby/The Canadian Press via AP
Wildfire smoke engulfs downtown Ottawa on June 5.
B.C. Wildfire Service via Reuters
Smoke billows upwards from a planned ignition by firefighters who were tackling the Donnie Creek Complex wildfire south of Fort Nelson, British Columbia, on June 3.
Communications Nova Scotia via Reuters
Firefighter Jason Rock sprays hot spots in the Birchtown area while tackling wildfires in Shelburne County, Nova Scotia, on June 3.
NASA
An astronaut aboard the International Space Station took this photo of wildfire smoke near Shelburne, Nova Scotia, on May 29. Human-caused climate change has exacerbated the hot and dry conditions that allow wildfires to ignite and grow.
B.C. Wildfire Service via Reuters
Smoke rises from a wildfire in Fort Nelson on May 27.
Kamloops Fire Rescue via Reuters
Firefighters stand on a truck while battling a blaze near Fort St. John, British Columbia, on May 14.
Anne-Sophie Thill/AFP via Getty Images
BJ Fuchs, a farmer who has lost some land and had to move his cattle due to the wildfires, stands in Shining Bank, Alberta, on May 11.
Scientists warn such routine-altering weather events are more likely to continue disrupting daily life as the planet warms, creating the ideal environment for more severe and frequent wildfires.
When flames burn, the smoke can travel thousands of miles, which puts millions more people in harm’s way.
Wildfire smoke is particularly dangerous because it contains tiny particulate matter, or PM2.5, the tiniest of pollutants. When inhaled, it can move deep into lung tissue and enter the bloodstream.
It comes from sources including the combustion of fossil fuels, dust storms and wildfires. Such smoke has been linked to several health complications including asthma, heart disease and other respiratory illnesses.