NEW YORK, June 7 (Reuters) – Schools across the U.S. East Coast canceled outdoor activities, air traffic slowed and millions of Americans were urged to stay home on Wednesday as smoke from Canadian wildfires drifted south and engulfed cities in a thick yellow haze.

The U.S. National Weather Service has issued air quality warnings along the Atlantic coast. Health officials from Vermont to South Carolina to western Ohio and Kansas have warned residents that spending time outdoors can cause respiratory problems due to high levels of fine particles in the atmosphere.

“It is critical that Americans suffering from dangerous air pollution, especially those with health concerns, listen to local officials to protect themselves and their families,” President Joe Biden said on Twitter.

AccuWeather, a private U.S. forecasting service, said the dense fog and smoke, extending from high elevations to ground level, was the worst explosion of wildfire smoke to blanket the northeastern United States in more than 20 years.

New York’s famous skyline, normally visible for miles, has disappeared in an unnatural smog, and some residents say they feel sick.

“It’s getting hard to breathe,” said Mohammad Abbas, walking along Broadway in Manhattan. “I was supposed to take a road test for my driver’s license today and it was canceled.”

The pollution was especially bad for outdoor workers like Chris Ricciardi, owner of Neighbors NV Landscaping in Roxbury, New Jersey. He said he and his crew were working shorter hours and wearing masks used for high pollen counts.

“We can’t afford to stop work,” he said. “We want to minimize exposure to smoke, but what can we actually do?”

Angel Emmanuel Ramirez, 29, a fashion designer at a Givenchy store in Manhattan, said he and his colleagues felt unwell and closed the store early after smelling smoke.

“It’s so intense you’d think there was a forest fire across the river, not in Canada,” Ramirez said.

New York Governor Cathy Hochul called the situation an “emergency crisis,” saying air pollution levels in parts of her state were eight times higher than normal.

Low visibility in the fog forced the Federal Aviation Administration to slow air traffic to the New York area along the East Coast and to Philadelphia in the upper Midwest.

Schools across the East Coast have suspended outdoor activities, including sports, field trips and recess.

A Broadway matinee of “Prima Face” was canceled after 10 minutes after poor air quality left actress Jodie Comer struggling to breathe. A production spokesperson said in a statement that the show has been rebooted with Dani Arlington set to play Tessa.

Major League Baseball was also affected, with the New York Yankees and Philadelphia Phillies postponing their home games scheduled for Wednesday. A National Women’s Soccer League game in Harrison, New Jersey, was also postponed, as was a WNBA women’s basketball game in Brooklyn.

In some areas, the air quality index (AQI), which measures key pollutants including particles from wildfires, defines 100 as “unhealthy” and 300 as “hazardous,” according to Aerno.

As of noon (1600 GMT), Bethlehem, Pennsylvania, recorded the worst air quality index in the country, with an AQI of 410. Among major cities, New York had the highest AQI in the world, at 342, as of Wednesday afternoon. According to IQAir, for chronically polluted cities such as Dubai (168) and Delhi (164).

Canadian Smoke Crossing

Smoke spread across the U.S. border from Canada, where hundreds of wildfires have burned 9.4 million acres (3.8 million hectares) and forced 120,000 people from their homes.

The sky above New York and many other North American cities grew progressively darker on Wednesday. The wind blew like burning wood.

Wildfire smoke has been linked to more heart attacks and strokes, increased emergency room visits for asthma and other respiratory illnesses, eye irritation, skin irritation and rashes.

A Manhattan Home Depot store was out of air fresheners and masks. New York Road Runners cancel events marking Global Running Day

“This is not the day to train for a marathon or have an outdoor event with your children,” New York Mayor Eric Adams advised. “If you are elderly or if you have heart problems or respiratory problems or if you are elderly, you should stay indoors.”

Pedestrians wore masks in numbers reminiscent of the worst days of the coronavirus pandemic.

Tyrone Sylvester, 66, has been playing chess in Manhattan’s Union Square for 30 years, but wearing a mask, he said he’s never seen the city’s air quality this bad.

“When the sun looks like this,” he said, pointing to a bronze orb visible in the smoky sky, “we know something is wrong. This is what global warming looks like.”

Poor air quality is expected to persist through the weekend, with a developing storm system expected to move smoke west over the Great Lakes and south into the Ohio Valley and mid-Atlantic, AccuWeather said.

Reporting by Tyler Clifford in New York and Denny Thomas in Canada; Additional reporting by Nancy Lapid, Julia Hart, Brad Brooks and Dan Whitcomb; Writing by Joseph Ochs and Steve Gorman; Editing by David Gregorio, Rosalba O’Brien and Jamie Freed

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