World's worst air quality: Canadian wildfires wreak new havoc on Chicago area

You wouldn't know it by looking outside, but it really was sunny Tuesday.

But smoke from Canadian wildfires blanketed the Chicago area, blotting out the sun here - as well as in much of the upper Midwest - with a dense haze reflecting the worst air quality here since the wildfires began.

The Illinois Environmental Protection Agency issued an air quality alert for Chicago and Rockford region through Wednesday night, citing "unhealthy" conditions and continued dangers for those with "sensitive respiratory systems." Some activities in the suburbs are being canceled.

People in the affected areas are urged to limit their time outdoors.

AirNow.gov, which monitors and tracks air quality throughout the country, listed the Chicago area in the "Very Unhealthy" category. As of 4 p.m., the website listed Chicago air quality at 258, the worst air quality of any major city in the world, ABC 7 Chicago reported.

Parts of Northwest Indiana, eastern Iowa and large patches of Michigan also were listed as "Very Unhealthy," the fourth-worst condition on the system's five-level scale.

The area has not reached the "Hazardous" air quality level, which is the worst.

When wildfire haze blanketed New York City earlier this month, the AQI peaked at 460, The New York Times reported, citing data from city and state agencies.

Wildfire smoke contains small particles called aerosols, some of which can worsen air quality and exacerbate respiratory and cardiovascular health problems.

The McHenry County Department of Health released an air quality alert active through Wednesday, recommending precautions to reduce exposure to the smoke. Those precautions include shortening time spent active outdoors, keeping windows closed overnight and reducing vehicle trips and idling.

For older adults, people with heart or lung disease, pregnant women, children and teenagers, the department recommends avoiding strenuous activities, keeping outdoor activities short and considering moving physical activities indoors or rescheduling them.

For those who choose to wear a face covering, the department noted that masks rated N95 or greater are the most effective at stopping fine fire particles.

Visibility also is down to one to three miles for much of the region, meteorologists at the National Weather Service's Romeoville bureau said. Besides the haze, the smell of the fires was more noticeable as the air stagnated from low wind speeds, meteorologists explained.

"This summer, cities across North America have seen unhealthy levels of air quality as a result of wildfire smoke, impacting over 20 million people from New York City, Washington, D.C., Montreal, and today here in Chicago," Chicago Mayor Brandon Johnson said in a statement Tuesday. "As we work to respond to the immediate health concerns in our communities, this concerning episode demonstrates and underscores the harmful impact that the climate crisis is having on our residents, as well as people all over the world."

Wheaton police officials canceled an event at Northside Park because of air quality issues. They are planning to reschedule at a later date.

The Batavia Park District closed Hall Quarry Beach through Wednesday, canceling both lessons and open swim. The Geneva Park District closed Sunset Pool at 4:30 p.m. Tuesday and advised people to check the RainOut app or telephone line, at (630) 206-1174, on Wednesday.

Though it is difficult to determine whether the fires are a direct result of climate change, experts say the unprecedented impact of the blazes is in line with the science - which says extreme weather events are likely to occur more frequently as the planet warms.

A storm system expected to move into the area later this week is anticipated to push out the haze and ultimately bring higher temperatures, according to weather service forecasts.

The wildfires, spurred on by dry conditions and unusually high temperatures, numbered 490 as of Tuesday. Half are considered "out of control," meaning the fires are expected to grow, according to the Canadian Interagency Forest Fire Centre. The fires have scorched more than 14 million acres since the start of the year, which is 15 times the 10-year average.

Since 1959, Canada has experienced a significant rise in the number of large fires and area burned, according to a 2018 study published in the Canadian Journal of Forest Research. The study reported that the country's fire season is starting approximately one week earlier and ending one week later than in the past.

A 2021 report from scientists at the Intergovernmental Panel on Climate Change further found that fire weather - dry, hot, windy conditions - has become more probable in many parts of the world and likely will become more common if global warming worsens.