Over 80 million people from the Midwest to the East Coast are under air quality alerts as smoke from the Canadian wildfires sweep across the U.S. border Tuesday, prompting beach closures, warnings about reduced visibility and calls to stay indoors.Canada is seeing its worst fire season on record with hundreds of wildfires raging across the country – more than 200 of them burning "out of control," according to the Canadian Interagency Forest Fire Centre. The wildfires have led to the highest emissions on record for the country, according to a Tuesday report from Copernicus.Video above: The kind of air conditioner filter you need to filter smoke from your homeAs smoke crosses into the U.S., air quality alerts have been issued for the entire states of Iowa, Wisconsin, Illinois, Indiana, Michigan, Delaware and Maryland as well are portions of Kansas, Missouri, Minnesota, Ohio, Pennsylvania, New York and Virginia, according to the National Weather Service. Residents are being advised to stay indoors with their air conditioning running or wear N95 masks if they have to be outside.Chicago had the worst air quality in the world Tuesday evening, according to IQAir. The city's Air Quality Index measured at 193 – a high reading designated as "unhealthy."The city has asked all residents – especially those with heart or lung disease, older adults, pregnant people and young children – to avoid outdoor activities and protect themselves from exposure. Chicago Public Schools and camps are also moving activities indoors, city officials said in a news release.Video below: Homemade air purifier can protect against wildfire smoke inside at homeAbout 11 miles away, Evanston, Illinois, is closing all swimming beaches and canceling a concert Tuesday due to the poor air quality, the city said on Facebook, asking residents to limit outdoor exposure through Wednesday. Across the state line in Michigan, the Mackinac Bridge stood covered with smoke Tuesday. Drivers were asked to drive slow and with caution due to the reduced visibility on the bridge. Detroit, Michigan, had the second worst air quality in the world Tuesday evening, with an "unhealthy" Air Quality Index is at 174, according to IQAir.High levels of fine particulate in the air in Michigan could become unhealthy or hazardous for all residents at some points – not just sensitive groups, the state's health department warned. "The most protective option when air is unhealthy for you is to stay indoors with air conditioning, reduce strenuous activities and limit outdoor activities. If you have to be outside, N95 masks offer enhanced protection when used according to product instructions," the Michigan Department of Health and Human Services said.Indianapolis drivers were also warned about reduced visibility, with the National Weather Service saying to "be prepared for haze that could suddenly reduce visibilities" in some areas Tuesday and Wednesday.Video below: Canada's provinces, territories sign on to national climate adaptation strategyNew York is also expected to see unhealthy levels of smoke return Wednesday and Thursday to some areas – about three weeks after New York City topped the list of the world's worst air pollution as smoke from the Canadian wildfires wafted south, turning skies orange. "New Yorkers should be prepared for elevated levels of fine particulate pollution caused by smoke on Wednesday and Thursday," Gov. Kathy Hochul said in a statement. "Current projections show the highest concentrations of smoke will slowly push east across the eastern half of New York State during the day Thursday, extending across much of the state."In Ohio, a spokesperson for the Cleveland's mayor's office said "what happened in NY a few weeks ago and Chicago today may happen here in Cleveland tomorrow."The Northeast Ohio Areawide Coordinating Agency issued an air quality advisory, forecasting fine particulate levels in the "Unhealthy" Air Quality Index range.Wildfire smoke carries particulate matter, or PM2.5 – a tiny but dangerous pollutant that, when inhaled, can travel deep into lung tissue and enter the bloodstream, according to the Centers for Disease Control and Prevention. The particulate matter has been linked to a number of health problems including asthma, heart disease and other respiratory illnesses.

NEW YORK —

On air quality maps, purple signifies the worst of it. In reality, it's a thick, hazardous haze that's disrupting daily life for millions of people across the U.S. and Canada, blotting out skylines and turning skies orange.

With weather systems expected to barely budge, the smoky blanket billowing from wildfires in Quebec and Nova Scotia and sending plumes of fine particulate matter as far away as North Carolina and northern Europe should persist into Thursday and possibly the weekend.

That means at least another day of a dystopian-style detour that's chased players from ballfields, actors from Broadway stages, delayed thousands of flights and sparked a resurgence in mask-wearing and remote work — all while raising concerns about the health effects of prolonged exposure to such bad air.

Video below: Poor air quality can have negative health effects

The weather system that's driving the great Canadian-American smokeout — a low-pressure system over Maine and Nova Scotia — "will probably be hanging around at least for the next few days," U.S. National Weather Service meteorologist Bryan Ramsey said.

"Conditions are likely to remain unhealthy, at least until the wind direction changes or the fires get put out," Ramsey said. "Since the fires are raging — they're really large — they're probably going to continue for weeks. But it's really just going be all about the wind shift."

Across the eastern U.S., officials warned residents to stay inside and limit or avoid outdoor activities again Thursday, extending "Code Red" air quality alerts in some places for a third straight day as forecasts showed winds continuing to push smoke-filled air south.

The smoke has moved over Greenland and Iceland since June 1, and was expected to reach Norway on Thursday, the Norwegian Climate and Environmental Research Institute said, but wasn't expected to be a health concern.

In Washington D.C., the roads were unusually clear as many stayed home and about half the people on the streets wore their pandemic-era masks. The local D.C. government canceled all outdoor activities at public schools and local senior centers, closed all public parks, suspended work by city road construction and paving crews, and delayed trash collection.

The poor air quality also forced the closing of the National Zoo, a popular tourist attraction in the nation's capital. Zoo officials said they were taking the action "for the safety of our animals, our staff and our guests."

In suburban Philadelphia, officials set up an emergency shelter so people living outside can take refuge from the haze.

New York Gov. Kathy Hochul said at a briefing Thursday in Albany that "this continues to be a public health crisis," with the worst air quality since at least the 1960s.

"This is not over. We might get a little respite, but I don't want people to let down their guard and to become complacent about this because we have to be prepared for the winds to shift. This is the unknown," Hochul said.

Video below: NY governor issues warning about air quality

The message seemed to be getting through. Hochul said state officials have not noticed a spike in people going to emergency rooms, though there were a few hospitals New York City reporting more patients coming in.

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. Other countries are also helping.

Canadian Prime Minister Justin Trudeau spoke to President Joe Biden by phone Wednesday. Trudeau's office said he thanked Biden for his support and that both leaders "acknowledged the need to work together to address the devastating impacts of climate change."

Canadian officials say this is shaping up to be the country's worst wildfire season ever. It started early on drier-than-usual ground and accelerated quickly. Smoke from the blazes has been flowing into the U.S. since last month but intensified with recent fires in Quebec, where about 100 were considered out of control Wednesday.

The smoke was so thick in Canada's capital, Ottawa, that office towers just across the Ottawa River were barely visible. In Toronto, Yili Ma said her hiking group canceled a planned hike this week, and she was forgoing the restaurant patios that are a beloved summer tradition in a nation known for hard winters.

"I put my mask away for over a year, and now I'm putting on my mask since yesterday," Ma lamented.

Eastern Quebec got some rain Wednesday, but Montreal-based Environment Canada meteorologist Simon Legault said no significant rain is expected for days in the remote areas of central Quebec where the wildfires are more intense.

In the U.S., federal officials delayed some flights bound Thursday morning for New York's LaGuardia Airport; Newark, New Jersey; and Philadelphia because smoke was limiting visibility. The Federal Aviation Administration said in a statement that it will likely need to take steps to manage the flow of air traffic into Washington, D.C., and Charlotte, North Carolina, as well.

Major League Baseball's Yankees, Phillies and Nationals had their games postponed. Hochul said air quality could affect the Belmont Stakes scheduled for Saturday in the New York City area.

On Broadway, "Hamilton" and "Camelot" canceled Wednesday performances and "Prima Facie" star Jodie Comer left a matinee after 10 minutes because of difficulty breathing. The show restarted with an understudy, show publicists said.

It was not to be at Central Park's outdoor stage, either. Shakespeare in the Park canceled its Thursday and Friday performances of "Hamlet," saying 'tis not nobler in the mind to suffer the slings and arrows of wretched air.