Canadian wildfire smoke, high heat, to blanket Long Island Thursday

A blanket of Canadian wildfire smoke, thick enough to block out the sun and hazardous enough to spur warnings for Long Islanders to stay inside, is forecast to remain stubbornly in place until late Thursday at the earliest.

The National Weather Service predicted "patchy smoke," high humidity and heat hitting 90 degrees Thursday. The temperature should drop to about 72 on Thursday night under smoky skies.

It will all be close to a repeat of Wednesday, when forecasters said the smoke from wildfires in Ontario, Canada, first settled in above Long Island, thickened by shifting winds and carrying a light scent of burning wood.

Just how bad it could get breathing the outside air remained an unanswered question, said weather service meteorologist David Stark on Wednesday.

"Whether there's going to be impact to us at the ground or not is still something that we're not completely sure of," Stark said. "There may be some smoke in the air. It could be high up, like what we saw yesterday, or ... we'll notice maybe a smell, or reduction of visibility."

Forecasters said it's unclear how long the smoky conditions would last. The next chance of smokeless skies is Friday, when the high tops out at about 87 with a mix of clouds and sun, according to the weather service's online forecast map. The forecast also calls for winds between 5 mph and 8 mph.

An air quality warning will remain in effect through midnight Thursday, with unhealthy conditions for all groups, according to the U.S. Air Quality Index. 

Late Wednesday, Gov. Kathy Hochul gave an update on the state's response, noting that more than 100,000 N95 masks were being "made available to counties in need to address air quality impacts."

"Distant wildfires have impacted New York State in recent years, and this week unfortunately will be no different with expected hazy skies and poor air quality," Hochul said in an earlier statement. "We are now closely tracking these conditions and I strongly encourage New Yorkers to stay informed and take appropriate precautions to stay safe. Sensitive groups should take particular caution."

The New York State Department of Environmental Conservation issued an air quality health advisory for Long Island and other parts of the state for Thursday. The advisory warned of fine particulate matter, also known as PM2.5. 

"These particles come in many sizes and shapes and can be made up of hundreds of different chemicals." the U.S. Environmental Protection Agency says on its website. "Some are emitted directly from a source, such as construction sites, unpaved roads, fields, smokestacks or fires. ... Some particles less than 10 micrometers in diameter can get deep into your lungs and some may even get into your bloodstream."

State Health Commissioner Dr. James V. McDonald cautioned that older residents and those predisposed to respiratory problems should remain indoors to avoid the effect of the airborne particulates generated by the wildfires. For anyone going outdoors Thursday, he recommended using an N95 mask.

It would also be a good idea to finish any outdoor work earlier in the day, McDonald added.

"When these tiny particles get breathed in by us ... these particulates get all the way down into our lungs ... and they can cause inflammation," McDonald told reporters on a conference call. "You're going to be better off inside" on days like Wednesday and Thursday, he said.

The state Department of Environmental Conservation's air quality index Wednesday rated eastern New York regions, including Long Island and New York City, as "unhealthy for sensitive groups." Air quality in western New York was rated "unhealthy" Wednesday afternoon.

After several years of enduring the smoke blown southeast from the Canadian wildfires, smoky skies have become an unwelcome and seemingly annual addition to summer on Long Island and throughout the Northeast.

K. Max Zhang, a sustainable energy systems expert at Cornell University who studies the effects of pollutants on air quality, said this year's smoke will not be as bad as the June 2023 wildfires that choked New York.

"The wildfire smoke now affecting New York is the latest example of what is becoming a new summer reality for the state," Zhang said in an email. "The pattern is increasingly clear: episodic wildfire-smoke pollution is no longer rare."

Newsday's Carl MacGowan contributed to this story.