Air quality in the US and Canada is improving but the smoke and disturbed skies will take time to clear

(CNN) — Air quality conditions in much of the eastern US are forecast to slowly improve this weekend after noxious air columns from hundreds of wildfires in Canada traveled south. However, schools in some metropolitan areas will operate remotely this Friday, as officials remain vigilant about exposure to contamination.

While the most severe conditions are over for most in the Northeast and Mid-Atlantic regions, potentially harmful air pollutants over cities including New York, Philadelphia and Washington are forecast to persist through Friday before areas slowly clear. in the next several days.

“Smoke from the Canadian wildfires continues to be carried south by winds toward the US, resulting in moderate to unhealthy air quality in parts of the Northeast, Mid-Atlantic, Ohio Valley, and the Midwest on Friday. Some improvements are expected this weekend,” the National Weather Service said.

Dense clouds of smoke have postponed professional sports games, canceled flights due to poor visibility; they have closed zoos and beaches and forced many to wear masks when outdoors. Climate experts have warned that such events are becoming more frequent due to human-induced climate change.

About 50 million people in several Midwestern and East Coast states were under air quality alerts, but that number may change this Friday as conditions improve for some.

Here’s what you can expect for this Friday:

• Air quality in entire states is compromised: all of Pennsylvania, Delaware, Connecticut, Rhode Island, New Jersey and Indiana are under air quality alerts. Parts of Ohio, Michigan, Maryland, Virginia, and North Carolina also continue to experience those alerts.
• Improvements in Canada: Most Halifax residents evacuated from the wildfires will be able to return home this Friday, Mayor Mike Savage said. Some 16,000 people fled their homes during the height of the wildfire evacuations and some 4,100 remain evacuated.
• remote classes: Potentially dangerous conditions have prompted officials in New York City, the nation’s largest school system, and Philadelphia to implement remote learning this Friday to help reduce exposure to air toxins.
• New York City: After experiencing the worst air quality in the world at various points this week, the Big Apple could see a “significant improvement” this Friday, Mayor Eric Adams said Thursday morning. “At this time, the smoke patterns do not indicate another large plume of smoke over the city,” Adams said as he urged people to wear a good mask when outdoors.
• Fire Fighting Assistance: This Friday, New York state plans to send rangers to help fight wildfires in Quebec, Governor Kathy Hochul announced Thursday. At least seven people will travel to Canada over the next two weeks, Hochul added. Federal resources have also been deployed, the White House has said.

Wildfire smoke from more than 400 fires in Quebec has stopped flowing south after several days of movement, eventually reaching and shrouding parts of the Atlantic coast in an orange haze. In Quebec, smoke from wildfires across the region has been reduced significantly.

As of early Friday morning, New York City’s air quality index was below 150, a designation considered “unhealthy for sensitive groups,” or a level 3 of 6, according to monitoring website AirNow.

Philadelphia’s air quality index topped 150 early Friday, making it “unhealthy.” City air is expected to improve slightly to “unhealthy for sensitive groups” later on Friday.

It should be noted, however, that the improvements are coming slowly with only light winds and little change to the current weather pattern, which will keep the smoke trapped closer to the ground until it slowly dissipates.

As of 2 a.m. Miami time Friday, several metropolitan areas still had “unhealthy” air quality levels, including Dover, Delaware; Richmond, Virginia; Atlantic City, NJ; and Raleigh, North Carolina.

But officials warn that such routine-disrupting weather events are more likely to continue to disrupt daily life as the planet warms, setting the stage for more severe and frequent wildfires. When those flames burn, the smoke can travel thousands of miles, endangering millions more.

The dangers of smoke to health

Smoke from wildfires is particularly dangerous because it contains tiny particles, or PM2.5, the tiniest of pollutants. When inhaled, it can penetrate deep into lung tissue and enter the bloodstream. It comes from sources including the burning of fossil fuels, dust storms, and wildfires, and such smoke has been linked to various health complications, including asthma, heart disease, and other respiratory diseases.

Because of those potential dangers, US President Joe Biden said Thursday that it is “very important” that communities experiencing air pollution pay attention to local guidance and check on their neighbors.

Dr. Peter DeCarlo, an associate professor in the Johns Hopkins University Department of Environmental Health and Engineering, urged people to closely monitor air quality in their vicinity and limit time outdoors.

“For this week, this is just a situation where we have a few days with pretty bad air quality. (…) It’s the beginning of summer for many of us who are parents, and maybe we can use it as an opportunity to not run so much until this poor air quality passes, “said DeCarlo.

— CNN’s Robert Shackelford, Laura Ly, Caroll Alvarado, Kristina Sgueglia, Sara Smart and Jen Christensen contributed to this report.