Photos: Canadian wildfires impact US air quality | CNN

A person on the subway in New York City wears a mask as smoky haze blankets a neighborhood on Wednesday, June 7.

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Workers chain up seats at Citizens Bank Park after the Philadelphia Phillies baseball game was postponed due to poor air quality in Philadelphia on June 7.

As haze and smoke cover the Manhattan skyline, two Orthodox Jewish men stand by the waterfront in Brooklyn on June 7.

Smoky haze diminishes the visibility of the Empire State Building in New York on June 7.

Andrew Elias attempts to photograph the sun obscured by smoke from the Canadian wildfires in Piermont, New York, on June 7.

Smoke blankets the Lincoln Memorial Reflecting Pool and the National Mall in Washington, DC, on June 7.

A person in Fort Lee, New Jersey, talks on his phone near the George Washington Bridge on June 7.

Smoke obscures the view from the New York State Thruway, looking north from West Nyack on June 7.

People wear face masks as they walk in New York's Herald Square on June 7.

John and Kristen Carson sit for lunch in Cincinnati on Tuesday, June 6. Smoke from the Canadian wildfires had drifted to the city, causing the air to appear hazy.

The sun rises over a hazy New York City skyline on June 7.

People at Toronto's CN Tower take photos of the smoky city on June 6.

A woman jogs along the Hudson River as a smoky haze hangs over the New York City skyline shortly after sunrise on June 7.

The sky is discolored during a New York Yankees baseball game on June 6.

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.

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.

The Statue of Liberty is obscured by the air pollution in New York on June 6.

Wildfire smoke engulfs downtown Ottawa on Monday, June 5.

Smoke billows upwards from a planned ignition by firefighters who were tackling the Donnie Creek Complex wildfire south of Fort Nelson, British Columbia, on Saturday, June 3.

Firefighter Jason Rock sprays hot spots in the Birchtown area while tackling wildfires in Shelburne County, Nova Scotia, on June 3.

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.

Smoke rises from a wildfire in Fort Nelson on May 27.

Firefighters stand on a truck while battling a blaze near Fort St. John, British Columbia, on May 14.

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.