NEW YORK (WABC) -- Smoke from Canadian wildfires covered New York City and the Tri-State in an unhealthy haze, holding up flights at major airports, postponing Major League Baseball games, and prompting people to wear pandemic-era face masks.
The streets of New York City turned hues of orange on Wednesday afternoon as the city topped the list of worst air quality in the world.
Mayor Eric Adams called the Air Quality Alert an, "unprecedented event in our city and New Yorkers must take precautions."
He said the Air Quality Index hit 484 at 5:00 p.m. - the max on the scale is 500. Anything above 300 on the government's air quality index is considered "hazardous."
The National Weather Service issued an Air Quality Alert for New York City and parts of the Tri-State area through Thursday.
The city will not be conducting outdoor activities on Thursday and alternate side parking is suspended.
Health officials are urging area residents to limit outdoor activities as air quality is expected to remain at "unhealthy" to "very unhealthy" levels.
That will leave the city's air quality advisory "in place for the next few days," Emergency Management Commissioner Zach Iscol said. "We expect this to be a multiple-day event. This is not something that is normal."
Adams says plans are underway to distribute masks at police and fire stations.
At a briefing on Wednesday evening, New York Governor Kathy Hochul said 1 million N95 masks will be made available across the state.
"(The smoke) has an immediate impact on people's health, irritation to the eyes, the nose, breathing, coughing, so and even shortness of breath," she said. "So our message right now is going to be reiterated multiple times because it is simply stay indoors, outdoors is dangerous and just about every part of our state, not just vulnerable communities."
New York City schools canceled all outdoor and afterschool activities and officials reminded parents that schools are already scheduled to be closed for students Thursday for Anniversary Day and Clerical Day.
The smoky haze is having a widespread impact. The FAA slowed flight traffic in and out of Newark and LaGuardia airports due to the poor visibility.
Major League Baseball postponed the Yankees game until Thursday. A National Women's Soccer League game in New Jersey and an indoor WNBA game set for Brooklyn were also called off Wednesday.
On Broadway, Wednesday's performance of "Hamilton" was canceled, while "Killing Eve" star Jodie Comer had difficulty breathing and left the matinee after 10 minutes; the show restarted with an understudy, show publicists said.
New Jersey closed state offices early, and some political demonstrations in spots from Manhattan to Harrisburg, Pennsylvania, were moved indoors or postponed. Striking Hollywood writers were pulled off picket lines in the New York metropolitan area.
WATCH | Toni Yates is live in New Jersey with updates on air conditions
Smoke from the wildfires in various parts of Canada has been lapping into the U.S. since last month but intensified with recent fires in Quebec, where about 100 were considered out of control Wednesday - which, unsettlingly, was National Clean Air Day in Canada.
RELATED | Canada wildfire status tracker
The smoke was so thick in downtown Ottawa, Canada's capital, that office towers just across the Ottawa River were barely visible. In Toronto, Yili Ma said her hiking plans were canceled and she was forgoing restaurant patios, a beloved Canadian summer tradition.
"I put my mask away for over a year, and now I'm putting on my mask since yesterday," the 31-year-old lamented.
Quebec Premier Franois Legault said the province currently has the capacity to fight about 40 fires - and the usual reinforcements from other provinces have been strained by conflagrations in Nova Scotia and elsewhere.
New York offered to send some fire rangers to deploy to Canada to help, Governor Hochul said on Wednesday.
U.S. National Weather Service meteorologist Zach Taylor said the current weather pattern in the central and eastern U.S. is essentially funneling in the smoke. Some rain should help clear the air somewhat in the Northeast and Mid-Atlantic this weekend or early next week, though more thorough relief will come from containing or extinguishing the fires, he said.
The smoke exacerbated health problems for some people. Exposure to elevated fine particle pollution levels can affect the lungs and heart.
Dr. Jack Caravanos is an environmental health expert at NYU who studies environmental toxins and pollution. He says because of the Canadian wildfires, the air quality is three times worse than normal.
"As time goes on, the air inside a building will ultimately equal the air outside, so for homes, restaurants, and delicatessens, the air quality inside will pretty much match the air quality outside, especially as this thing goes on for a few days," Caravanos said.
Kids, who often are encouraged to go out and play, "are more susceptible to smoke for a number of reasons," said Laura Kate Bender, the lung association's National Assistant Vice President, healthy air. "Their lungs are still developing, they breathe in more air per unit of body weight."
VIDEO | Marcus Solis reports on conditions in White Plains:
A toll-free air quality hotline has been established so New York residents can stay informed on the air quality situation. The toll-free number is 1-800-535-1345.
The Associated Press contributed to this report.
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