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Poor air quality expected to linger 'the next few days' in the northern U.S.

Smoke from ongoing wildfires in Canada is creating unhealthy haze across the Midwest.
A person rides a bicycle along the shore of Lake Michigan as the downtown skyline is blanketed in haze from Canadian wildfires Tuesday, June 27, 2023, in Chicago.
A person rides a bicycle along the shore of Lake Michigan in Chicago as the downtown skyline is blanketed in haze from Canadian wildfires Tuesday. Kiichiro Sato / AP

Unhealthy air in the U.S.

  • Smoke from Canadian wildfires is blanketing Chicago and much of the Great Lakes region, creating unhealthy air quality conditions.
  • Chicago and Detroit were among the top three cities with the worst air quality in the world late Tuesday, according to, a tracking service.
  • The National Weather Service has issued air quality alerts for northeastern Illinois, northwestern Indiana and all of southeast Michigan for Tuesday and Wednesday.
  • Around 92 million people in the U.S. were under air quality alerts Tuesday evening.

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158d ago / 4:28 AM UTC

Poor air quality could last for a few days in the U.S. because of fires

The northern part of the U.S. near the Great Lakes could have poor air quality for “the next few days” thanks to a low-pressure system, the National Weather Service said tonight.

The forecast area of low pressure “will tap the ongoing wildfire smoke of south central Canada, sending it southward in the counter clockwise flow,” the weather service said in a forecast discussion.

Health officials in affected areas today issued air quality alerts. The Illinois Environmental Protection Agency issued an air quality alert until midnight tomorrow night, and Wisconsin’s air quality advisory lasts until Thursday at noon.

New York state is also expected to have deteriorating air quality tomorrow and New York City on Thursday, Gov. Kathy Hochul said.

158d ago / 3:58 AM UTC

How to scrub pollutants from indoor air

Indoor air filters can help reduce or remove pollutants, including small particulate matter from wildfire smoke. The tiny particles, measuring less than 2.5 micrometers in diameter, or roughly 4% the width of a strand of hair, are small enough to be breathed deep into the lungs and can enter the bloodstream. Studies have found that even short-term exposure to small particulate matter increases the risk of a variety of cardiovascular and respiratory diseases.

Health officials recommend that people stay indoors as much as possible when air pollution levels are elevated. Indoor air filtration, including HVAC systems (heating, ventilation and air conditioning) and portable air purifiers, can also help scrub pollutants that may have traveled inside homes and other buildings.

People can buy portable air cleaners with replaceable HEPA filters that strain out small particulate matter, or PM2.5. HEPA filters are also available for homes outfitted with central heating and cooling systems. California’s Environmental Protection Agency recommends using an indoor air cleaner any time the air quality index hits “unhealthy” levels or if people see or smell smoke in the air. 

But people can also make their own indoor air cleaners by attaching air filters to box fans with tape, brackets or bungee cords. If window air conditioning units, HVAC systems or portable air cleaners are not available, the U.S. Environmental Protection Agency said, “DIY air cleaners” can serve as “a temporary alternative to commercial air cleaners.” The agency cautioned that DIY air cleaners should not be used routinely and that concerns have been raised about the potential fire or burn risk if box fans overheat.

The EPA added that there is limited research on the effectiveness of DIY air cleaners, but a study published in July 2021 in the journal Aerosol and Air Quality Research found that low-cost filtration methods, including attaching a filter to a box fan, “can have significant benefit for filtering submicron smoke particles and may reduce exposure to PM2.5 during wildfire smoke events.”

158d ago / 3:33 AM UTC

Latest round of smoke in Wisconsin is most significant for state this season

The latest round of Canada wildfire smoke affecting Wisconsin is producing the most significant air quality impact across the state so far this season, the state Department of Natural Resources said today.

An air quality advisory was in place through noon Thursday — although the worst effects are forecast to be between now and noon tomorrow, it said.

State officials urge everyone to keep activities outside short. “Watch for symptoms like coughing and shortness of breath as a sign to take a break or move indoors,” the department said

Smoke was triggering air quality alerts in other places, as well, including Chicago and elsewhere in Illinois.

The air quality index in Milwaukee, Wisconsin’s largest city, was 256, or considered “very unhealthy,” tonight, according to the U.S. government website

158d ago / 2:21 AM UTC

How much do air purifiers help?

The Environmental Protection Agency says portable air purifiers with HEPA filters can be reduce indoor particle concentrations by as much as 85%

Experts say consumers should look for air purifiers that have a clean air delivery rates — a metric of how effective they are at removing pollutants — of at least two-thirds the size of the room they are intended for.

For most rooms, a clean air delivery rate equal to 300 or more cubic feet per minute should be enough, said Dr. Barbara Mann, a pulmonologist and assistant professor of medicine at the Icahn School of Medicine at Mount Sinai in New York.

To maximize air purifiers’ effectiveness, change filters at the recommended intervals, she said. Keep windows closed when filters are being used. When people come in from extended periods outside in areas of poor air quality, they should change their clothes, take off their shoes and shower, she said.

Pollutants can come from indoor sources, too, said Dr. Peter Moschovis, a pulmonologist and critical care physician at Massachusetts General Hospital and an assistant professor at Harvard Medical School.

“Don’t generate extra particles indoors if you can,” he said. “So, smoking, vaping, burning incense, aerosolized essential oils — all those things aren’t good for your lungs at baseline.”

158d ago / 2:06 AM UTC
158d ago / 1:33 AM UTC

Detroit residents were hit hard by smoke weeks ago

Detroit, for a second time this month, was listed today as having the worst air quality in the world, alternating with Chicago on IQAir’s list because of Canada wildfire smoke.

NBC News reported weeks ago, during the first round of smoke that blanketed parts of the U.S., the concerns of residents of the predominantly Black city over air quality, concerns that preceded the fires.

A 2020 poll by the Environmental Defense Fund, a nonprofit advocacy group, found that 58% of Black adults living in Detroit are twice as likely as white residents to be concerned about air pollution in their communities.

Poor air quality conditions are even worse in regions like southwest Detroit, where residents are hospitalized for asthma three times more than the state average.

158d ago / 1:19 AM UTC

Robocalls, billboards used in Chicago amid smoke concerns

Officials in Chicago are using robocalls to senior citizens and billboards to help inform residents about the poor air quality.

“We just want to continue to push out the message that if you feel symptoms that could be potentially caused by this poor air quality, we want you to call 911,” Chicago Mayor Brandon Johnson's chief of staff, Rich Guidice, told reporters.

So far today, calls to the city’s fire department have been “very, very low,” considering the circumstances, he said.

“It’s something we’re going to continue to monitor throughout the rest of the evening and throughout tomorrow,” Guidice said.

He said Chicagoans should act as they do during storms or other extreme weather events, including checking on neighbors.

158d ago / 12:51 AM UTC

Rain likely won’t be enough to extinguish Quebec wildfires 

MONTREAL — Rain likely won’t be enough to extinguish the wildfires ravaging northern Quebec, but the wet weather could give firefighters a chance to get ahead of the flames, officials said, as Canada surpassed the record for area burned by wildfires this week.

Drifting smoke from wildfires across Canada is creating curtains of haze and raising air quality concerns throughout the Great Lakes region and in parts of the central and eastern United States.

Meanwhile, NASA reports that smoke from wildfires in northern Quebec has reached Europe. The space agency said satellite imagery from yesterday showed smoke extending across the North Atlantic Ocean to the Iberian Peninsula, France and other parts of western Europe.

158d ago / 12:39 AM UTC

Graphic: How large are the harmful particles in wildfire smoke?

158d ago / 12:33 AM UTC

Chicago Cubs game goes on despite smoke

The Chicago Cubs' home game began tonight as scheduled despite air quality alerts covering Illinois and other states.

Fans arrive prior to the game between the Chicago Cubs and the Philadelphia Phillies at Wrigley Field on June 27, 2023 in Chicago, Illinois. A air quality alert was issued due to smoke from Canadian wildfires.
Fans arrive before the game between the Chicago Cubs and the Philadelphia Phillies at Wrigley Field in Chicago on Tuesday.Michael Reaves / Getty Images

Chicago and Detroit had the first- and second-worst air quality in major cities in the world today, according to tracking service Chicago had an air quality index of 178 shortly before the first pitch was to occur, according to the website.

An AQI of 100 to 150 is considered unhealthy for sensitive groups, and 151 to 200 is considered unhealthy, according to, a U.S. government website.

Major League Baseball did not immediately respond to a request for comment.

Earlier this month during another wildfire smoke event from Canada fires, the MLB postponed two games because of air quality.

The games between the Chicago White Sox and the Yankees in New York and the Detroit Tigers and the Phillies in Philadelphia that were to have been played June 7 were instead made up later. A Washington Nationals home game against the Atlanta Braves scheduled for June 8 was also postponed.

The Chicago White Sox, the Detroit Tigers, the Milwaukee Brewers and the Minnesota Twins were playing away games tonight.

158d ago / 12:11 AM UTC

Ohio also warns residents

Health authorities in Ohio joined those in other states in warning residents to take precautions because of unhealthy air because of Canada wildfire smoke.

It’s the second time in three weeks that smoke from the wildfires drifting south has caused air quality problems in Ohio, said Bruce Vanderhoff, director of the state Health Department, in a statement.

“It is important to take poor air quality seriously, as exposure to smoke can cause health problems,” Vanderhoff said. “Certain groups of people are at higher risk, such as those with chronic heart or lung disease, children, the elderly, and pregnant women. Please take precautions until these conditions improve.”

158d ago / 11:52 PM UTC

Evacuations ordered after wildfire erupts in Southern California

Dozens of homes were under evacuation and an unknown number of buildings burned after a wildfire erupted in Southern California, officials said.

The Juniper Fire ignited this afternoon in the community of Perris, roughly 70 miles southeast of Los Angeles, and had grown to 50 acres by 4 p.m., the Riverside County Fire Department said.

The blaze was 0 percent contained, the fire department said.

A spokeswoman for the fire department said the blaze prompted mandatory evacuation orders for about 88 homes. The spokeswoman, Maggie Cline De La Rosa, said officials had confirmed structures had burned though it was not clear how many had been destroyed or damaged.

Aerial video from NBC Los Angeles showed what appeared to be a house engulfed in flames. A separate video from the fire department showed flames approaching another house.

158d ago / 11:45 PM UTC

Minnesota breaks poor air quality record

Smoke from the wildfires moved into Minnesota late yesterday, and ground-level smoke is expected to linger across southern, east-central and northeastern Minnesota. That includes the Twin Cities area up to the northeast corner of the state and down to the southwest and southeast corners.

The Minnesota Pollution Control Agency tweeted that today marked the 23rd air quality alert in Minnesota this year, breaking the previous record of 21 in 2021. Minnesota usually averages two or three alerts in a season.

St. Paul recorded the worst air quality in the U.S. two weeks ago because of smoke from Canadian wildfires. As of midday today, the air quality was rated “unhealthy” across eastern Minnesota from the Canadian border to the Iowa border.

The Pollution Control Agency said a cold front will move across Minnesota tomorrow, bringing cleaner air from the West across the region by early Thursday.

158d ago / 11:09 PM UTC

Models show smoke in eastern U.S. cities tomorrow 

Smoke from wildfires in Quebec could smother eastern cities, including New York and Boston, tomorrow afternoon. 

The BlueSky Canada system, which combines fire information with weather modeling to forecast smoke dispersal, predicts that the unhealthy concentrations of smoke will travel southeast from Quebec and cover those cities at around 3 p.m. ET

A similar smoke prediction model powered by the National Oceanic and Atmospheric Administration tells a different story. It predicts surface smoke will travel toward the eastern U.S. later tomorrow, covering Pittsburgh, Raleigh, North Carolina, and other cities.

Both models are experimental, and the situation will develop further overnight. Smoke impacts are notoriously difficult to forecast, because they depend on myriad weather and fire behavior factors.

158d ago / 10:58 PM UTC

The Midwest is no stranger to elevated air pollution

Even before smoke from Canada’s wildfires wafted over Illinois, Indiana, Wisconsin, Minnesota and Michigan, many major cities across the Midwest were experiencing elevated levels of air pollution, according to data from, which is run by the Environmental Protection Agency.

Charts showing recent trends in air quality levels indicated, for instance, that Chicago has had only two days in June when air quality was considered “good.”

This chart shows air quality levels for the city of Chicago over the past 30 days.
This chart shows air quality levels for the city of Chicago over the past 30

Detroit similarly has had only two days this month with “good” air quality, according to AirNow.

St. Louis has also struggled with elevated levels of air pollution, logging just one day in June with “good” air quality.

Meanwhile, Indianapolis, Minneapolis, Milwaukee and parts of nearby Ozaukee County, Wisconsin, have each had just three days of “good” air quality this month.

158d ago / 10:45 PM UTC

92 million under air quality alerts in U.S.

Around 92 million people in the U.S. were under air quality alerts this evening as smoke from Canada wildfires again affected parts of the country, according to NBC’s Weather Unit.

Some state government agencies and others warned residents to limit their time outdoors because of wildfire smoke, which was also affecting visibility.

Air quality alerts covered a large part of the Midwest, including all of Iowa, Illinois, Wisconsin, Michigan and Indiana, according to the National Weather Service.

Other states, including parts of Pennsylvania and New York, were also under the alerts.

158d ago / 10:39 PM UTC

Iowa also under air quality alert because of smoke

Officials in Iowa joined those in other Midwestern states in issuing air quality alerts and warning residents to limit time outdoors because of the return of wildfire smoke from Canada fires.

“Here we go again, another day engulfed in wildfire smoke,” the National Weather Service for the Quad Cities area of Iowa and Illinois tweeted.

Iowa’s Department of Natural Resources said that there was an air quality advisory through tomorrow and that conditions were worse in the eastern part of the state.

Officials said that people should reduce long or intense outdoor activities and take breaks and that those with heart or lung conditions and outdoor workers are particularly at risk.

158d ago / 10:15 PM UTC
158d ago / 10:03 PM UTC

Wisconsin issues statewide advisory on air quality

The Wisconsin Department of Natural Resources issued a multiday advisory because of the wildfire smoke, saying the air quality could be affected through noon Thursday.

158d ago / 9:58 PM UTC

Detroit’s air quality is among the worst in the world

Detroit's air quality ranks second-worst of any major city in the world, according to, an air pollution tracking service operated by a Swiss technology company.

A statewide air quality advisory has been issued in Michigan as pollution levels in some areas spike into “unhealthy” and “hazardous” ranges.

“For vulnerable adults and all children, staying indoors with air conditioning on and windows and outside doors shut is one of the best options when outdoor air is unhealthy,” Michigan’s Department of Health and Human Services tweeted.

158d ago / 9:52 PM UTC

Canadian wildfire season is worst on record – and just getting started

Canada is having its worst fire season on record, with more than 19 million acres burned, according to data from the Canadian Interagency Forest Fire Centre. The agency lists statistics of the total area burned across the country for every year dating to 1983

Some 487 fires were burning across the country as of 5:30 p.m. ET, the agency reported. Nearly 260 of them were considered “out of control.”

A prolonged spring heat wave in northern Canada primed the landscape for fire. Beginning in April, an omega block pattern of high pressure centered on parts of northern Canada, which sent temperatures soaring to record levels and dried out vegetation. The country has been on its highest level of alert for wildfires since May 11. 

The unusual pattern is consistent with what climate scientists have predicted for Canada as the world warms as a result of human use of fossil fuels. 

Wildfire activity in Canada typically peaks in early to mid-July, and the danger this year is unlikely to abate for months. Monthly forecasts suggest fire severity will be “well above average” in western Canada through September.

158d ago / 9:45 PM UTC

Video shows haze blanketing Chicago skyline

A Chicago resident captured haze blanketing the city's skyline this morning.

Larysa Gierut, a resident of Chicago, went out to fly a drone by the Adler Planetarium this morning to record what she thought was fog, but then she realized it was haze and smoke.

Gierut said that her clothes smelled like fire when she went home and that she plans to stay home until the skies clear up.

"I called my daughter to come home, too," she said. "She ran home fast."

158d ago / 9:41 PM UTC

As smoke hits Midwest, Southern states hit by sweltering temperatures

Though Midwest and East Coast states are bracing for terrible air conditions, Southern states are dealing with a third week of oppressive heat.

Heat records are being broken across Texas. San Angelo hit a record high of 112 degrees Fahrenheit on Sunday, surpassing the previous record of 104 in 1994. That same day, Del Rio set a record high temperature, hitting 110.

In addition to the records set in Texas, forecasters say more could fall later this week as triple-digit temperatures are expected in parts of Missouri, Arkansas, Tennessee, Texas and Louisiana.

Warnings and advisories for excessive heat are also in place across the Southwest and parts of New Mexico, Oklahoma, Arkansas, Louisiana, Mississippi, Alabama and Florida, according to the National Weather Service.

158d ago / 9:35 PM UTC

Chicago air quality alert in effect until midnight Wednesday

Chicago officials warned residents that air quality in the city is considered "very unhealthy," adding that people should limit time outdoors.

The city’s Office of Emergency Management & Communications tweeted that an air quality alert will remain in effect until midnight tomorrow.

Officials also issued guidance about how to stay safe as air pollution spikes in the region. Recommendations include staying indoors, keeping windows and doors closed and wearing masks if people venture outside.

158d ago / 9:27 PM UTC

New York governor tells residents to prepare for smoke's return

New York Gov. Kathy Hochul released a statement warning people in the state to take precautions and brace for bad air quality in the coming days.

Hochul's office said the smoke from the Canadian wildfires is expected to once again affect the region tomorrow and Thursday. The state Department of Environmental Conservation issued a health advisory for the western New York, central New York and eastern Lake Ontario regions.

"Over the next ... 48 hours we're anticipating the smoke and the haze to come all across the state," Hochul said. "We've been watching this and monitoring this, and it's going to enter the New York skies tomorrow morning, with Western and Central New York hit first Wednesday. And by Thursday, you're going to see smoke affecting New Yorkers here in the city as well."

Expectations for the air quality index will reach as high as 200, or "very unhealthy" levels, and Hochul warned that conditions can deteriorate very quickly.

Authorities are making N95-style masks available at major transit hubs, and they will be distributed across the state.

158d ago / 9:22 PM UTC

What the Air Quality Index numbers mean

Air quality is measured on an index of 0 to 500, according to the Environmental Protection Agency's AirNow website.

The number corresponds to the concentration of pollutants in the air, with anything under 100 considered to be satisfactory and increasing toward 500 the worse the quality becomes. The scale is also color-coded, with 0 to 100 in the green zone of "good" and anything above 300 labeled as maroon, or "hazardous," the website says.

Chicago's air quality by this afternoon was 181, according to That put it in the "unhealthy" red category, putting more sensitive groups at risk for serious health effects.

158d ago / 9:22 PM UTC

Air quality tanks in Midwest as Canadian wildfires continue to rage

Just weeks after an orange haze descended on the East Coast, wildfire smoke from Canadian wildfires caused air quality to plummet in the Midwest today.

Chicago had the worst air quality in the world by this afternoon, according to, a tracking service. Second on the list was nearby Detroit.

The Illinois Environmental Protection Agency issued an air quality alert in effect until midnight tomorrow and encouraged Chicago residents to limit their time outdoors. Chicago Mayor Brandon Johnson said the city is monitoring the situation.

The National Weather Service has issued air quality alerts for northeastern Illinois, northwestern Indiana and all of southeast Michigan for today and tomorrow.