Millions of people in North America have been advised to wear N95 masks outdoors due to poor air quality levels sparked by intense wildfires in Canada.
New York will begin distributing free masks on Thursday. Canada has said that people should wear a mask if they are unable to remain indoors.
Officials warn that the dangerously smoky conditions are expected to persist into the weekend.
Much of the smoke is coming from Quebec, where 150 fires are burning.
More than 15,000 residents are expected to be forced to evacuate in the province, officials said on Wednesday. It is already Quebec’s worst fire season on record.
New York Governor Kathy Hochul announced on Wednesday that New York would distribute one million masks to state residents on Thursday.
“This is a temporary situation. This is not Covid,” she said at a news conference. The governor added that New York City buses and trains have high-quality air filtration systems that make them safe forms of travel.
Environment Canada has said that conditions are worsening in Toronto on Thursday, as more smoke pours in.
Meanwhile… Flights at major New York airports have been delayed as smoke from a series of wildfires in Canada limited visibility.
The US Federal Aviation Administration (FAA) warned travellers to expect flights to be delayed by up to two hours at New York’s LaGuardia airport and nearby Newark International.
Some 800 flight delays at New York City airports were reported by 19:50 EST (03:50 BST), according to Flight Aware.
Millions of people are under air quality alerts in both countries.
The air travel bottleneck has had a ripple effect, postponing flights at airports from Atlanta to Houston. Inbound flights to Philadelphia’s main airport were also affected.
About 250 flights were delayed at Toronto Pearson International Airport.
New York City’s LaGuardia airport told passengers: “Weather conditions have caused LGA Airport flight disruptions. Check with your airline to determine the status of your flight.”
As Canadian firefighters struggle to control the 400 wildfires raging across the country, smoke blanketed much of the eastern part of the country and the East Coast. The haze blotted out New York City’s famed skyline and drew comparisons to Mars and a post-apocalyptic scene.
Health officials in both countries have issued warnings about potentially dangerous air quality and pollution.
There are more than 150 fires burning in Quebec alone, but according to the province’s premiere, Francois Legault, there are only enough firefighters to tackle 40 of the infernos.
At a news conference Wednesday, Canadian Prime Minister Justin Trudeau said more than 230 fires are raging out of control and more than 20,000 people have evacuated their homes.
“Firefighters are stepping up. First responders are stepping up in harrowing situations to save their fellow citizens,” Mr Trudeau said.
If fires continue to burn at this rate, Canada could be facing its worse wildfire season on record. So far this season, approximately 3.8 million hectares (9.39 million acres) of land has burned.
The White House has said it will send support to Canada to help battle the fires.