A man wears a mask as he crosses an intersection in a haze-filled sky of Manhattan, New York, Wednesday, June. 7, 2023. Smoke from Canadian wildfires poured into the U.S. East Coast and Midwest on Wednesday, covering cities in both nations in an unhealthy haze, holding up flights at major airports and prompting people to fish out pandemic-era face masks. (Photo by Yuki Iwamura/AP Photo)





A commuter steps into the subway as smoke from wildfires in Canada partially obscure One World Trade Center in lower Manhattan, Tuesday, June 6, 2023, in New York. (Photo by Daniel P. Derella/AP Photo)





People attend a morning yoga class on The Edge observation deck as a haze caused by smoke from wildfires burning in Canada hangs over Manhattan in New York, USA, 07 June 2023. An air quality alert was issued for the whole of New York City as a result of the smoke, which affects large portions of the northeastern United States. (Photo by Justin Lane/EPA)





A woman looks at the Manhattan skyline engulfed in haze caused by smoke from wildfires burning in Canada, in New York, USA, 07 June 2023. (Photo by Justin Lane/EPA)





People look out over Manhattan enveloped in a dense haze caused by wildfires in Canada on June 06, 2023 in New York City. Over 100 wildfires are burning in the Canadian province of Nova Scotia and Quebec resulting in air quality health alerts for the Adirondacks, Eastern Lake Ontario, Central New York and Western New York. (Photo by Spencer Platt/Getty Images)





People wear masks as they wait for the tramway to Roosevelt Island as smoke from Canadian wildfires casts a haze over the area on June 7, 2023 in New York City. Air pollution alerts were issued across the United States due to smoke from wildfires that have been burning in Canada for weeks. (Photo by Eduardo Munoz Alvarez/Getty Images)





U.S. President Joe Biden reacts as Quarterback Patrick Mahomes and Tight End Travis Kelce present him with a personalized jersey of the Kansas City Chiefs during the team's visit to the White House to celebrate their championship season and victory in Super Bowl LVII, in Washington, U.S., June 5, 2023. (Photo by Evelyn Hockstein/Reuters)





A person jumps at Apple's annual Worldwide Developers Conference at the company's headquarters in Cupertino, California, U.S. June 5, 2023. (Photo by Loren Elliott/Reuters)





The Apple Vision Pro headset is displayed in a showroom on the Apple campus in Cupertino, Calif., at the company's annual developers conference, Monday, June 5, 2023. (Photo by Jeff Chiu/AP Photo)





People attend Apple's annual Worldwide Developers Conference at the company's headquarters in Cupertino, California, U.S. June 5, 2023. (Photo by Loren Elliott/Reuters)





A landslide under the historic Casa Romantica in San Clemente suspends rail service in the area as officials asses the situation in San Clemente, California, U.S., June 5, 2023. (Photo by Mike Blake/Reuters)





A commercial airplane takes off over the Iwo Jima Marine Corps Memorial in Arlington, Va., on Wednesday, June 7, 2023. Heavy smoke from Canadian wildfires were visible throughout the region Wednesday. (Photo by Tom Brenner for The Washington Post)





A passenger wearing a face mask rides the Staten Island Ferry past the Statue of Liberty during heavy smog in New York on June 6, 2023. Smoke from Canada's wildfires has engulfed the Northeast and Mid-Atlantic regions of the US, raising concerns over the harms of persistent poor air quality. (Photo by Ed Jones/AFP Photo)





A performer plays the violin as a passerby wears a mask in Times Square as Manhattan is shrouded in haze and smoke which drifted south from wildfires in Canada, in New York City, New York, U.S., June 7, 2023. (Photo by Maye-E Wong/Reuters)





A parade participant dances during the 2023 WeHo Pride Parade in West Hollywood, California, USA on June 4, 2023. (Photo by Caroline Brehman/EPA)





Pyrotechnics go off as Kyle Busch, driver of the #8 3CHI Chevrolet, and Ryan Blaney, driver of the #12 Menards/Richmond Water Heaters Ford, lead the field on a pace lap prior to the NASCAR Cup Series Enjoy Illinois 300 at WWT Raceway on June 04, 2023 in Madison, Illinois. (Photo by Jonathan Bachman/Getty Images)





A person waiting for the subway wears a filtered mask as smoky haze from wildfires in Canada blankets a neighborhood on June 7, 2023 in the Bronx borough of New York City. New York topped the list of most polluted major cities in the world on Tuesday night, as smoke from the fires continues to blanket the East Coast. (Photo by David Dee Delgado/Getty Images)





Smoke from Canada wildfires at sunrise in Jersey City, New Jersey, US, on Wednesday, June 7, 2023. New York was the most polluted major city in the world on Tuesday night, as smoke from Canadian wildfires blanketed the city in haze, according to the IQAir website. (Photo by Yuki Iwamura/Bloomberg)





Wearing protective face masks, U.S. Park Rangers stand at the base of the Washington Monument on Wednesday, June 7, 2023. Heavy smoke from Canadian wildfires were visible throughout the region Wednesday. (Photo by Tom Brenner for The Washington Post)





People wear protective masks as the Roosevelt Island Tram crosses the East River while haze and smoke from the Canadian wildfires shroud the Manhattan skyline in the Queens Borough New York City, U.S., June 7, 2023. (Photo by Shannon Stapleton/Reuters)