Air quality alerts, wildfire smoke from Canada may linger in US for days: Live updates

New Yorkers woke up to the worst urban air quality in the world Thursday and millions of Americans could face days or even weeks of smoky siege from the drifting haze of unrelenting Canadian wildfires.

The low-pressure system adrift over Maine and Nova Scotia that has helped funnel the ashen air will probably be "hanging around at least for the next few days,” National Weather Service meteorologist Bryan Ramsey said. Conditions are likely to remain unhealthy until the wind direction changes or the fires are doused, he said.

“Since the fires are raging, they’re really large, they’re probably going to continue for weeks," Ramsey said. "It’s really just going be all about the wind shift.”

The good news, AccuWeather reports, is that parts of the Northeast could see modest air quality improvements though the day Thursday, although it will take until Friday or Friday night for significant improvement in some locations. The bad news is some of the most dense smoke may shift west toward Pittsburgh, Cleveland and Detroit, AccuWeather said.

Canada wildfire smoke updates: At least 100 million Americans affected by air quality alerts

Developments:

∙The air quality monitoring website iqair.com had New York City at the top of its list. Tel Aviv in Israel was second, but Detroit was third.

∙Authorities warned residents across much of the Northeast to stay inside and limit or avoid outdoor activities Thursday, extending “Code Red” alerts in some places for a third-straight day

∙Low visibility from the haze forced a "ground stop" on all flights out of New York's LaGuardia Airport early Thursday.

Fires could roar for weeks

More than 400 blazes burning across Canada have left 20,000 people displaced. The U.S. has sent more than 600 firefighters and equipment to Canada. A primary culprit for fouling U.S. air is the 150 fires burning in south-central Quebec, a majority of which were not contained. A stalled high pressure system over the northern Plains and the stationary low pressure system over eastern Canada has produced a "steering" wind from north to south, sending thick plumes of smoke into the Northeast, Middle Atlantic and Ohio Valley, AccuWeather Senior Meteorologist Brett Anderson said.

The fires are mostly in remote, wooded areas −and since most of Canada's firefighting focus is on saving homes, the blazes are likely to continue burning into the summer, Anderson said.

"So get used to these episodes of smoke and haze through the summer," he said.

Surreal photos show NYC covered in glowing orange haze from Canada wildfire smoke

New Jersey could move out of red alert status today

An air quality alert remains in effect for New Jersey through Thursday night. It is forecast to drop on Thursday from a red alert, which means it's unhealthy for the general population, to an orange alert – unhealthy for sensitive groups.

"We're looking at this staying with us to some degree Thursday and into Friday," said National Weather Service meteorologist John Cristantello.

–Scott Fallon, northjersey.com

New York state distributing 1 million N95 masks

One million N95 filtering masks will be made available across New York state Thursday, Gov. Kathy Hochul said. More than 400,000 will be distributed to New Yorkers at subway and bus stations and state parks, with another 600,000 made available for local governments to pick up and distribute.

“You don’t need to go out and take a walk. You don’t need to push the baby in the stroller,” Hochul said Wednesday night. “This is not a safe time to do that.”

Contributing: The Associated Press