Hazy skies for Chicago brought on by smoke from Canadian wildfires

CHICAGO (CBS) -- Light amounts of pollution are smearing the skyline in Chicago on Tuesday, and minor air quality issues are expected to continue Wednesday.

A combination of ozone pollution from stagnant air and smoke from Canadian wildfires rotating around a western high pressure ridge are downgrading air quality in our area today.

Air quality is expected at times to dip into the "Unhealthy for Sensitive Groups" category Tuesday, meaning those with respiratory conditions, elderly folks and young children should limit outdoor exertion. Other segments of the population are fine to continue their normal activities, according to the Environmental Protection Agency.

Canadian wildfire smoke was a major health issue in the Chicago area at times during summer 2023 , when air quality was occasionally downgraded into the "Unhealthy for All" category.

By early July, Chicago's air pollution was the worst it had been in more than a decade , thanks to a combination of smoke from Canadian wildfires, and other factors including Fourth of July fireworks, heavy rain, and even the NASCAR Street Race hitting the city's pavement on city streets.

"It's all coming at once and it's all coming in one year," Jen Brady, a senior data analyst with the nonprofit Climate Central, said last July.

Brady said it all has an impact, calling it "compounding events," all of which affect the air even for short periods of time.

This minor brush with wildfire smoke this week will not be as significant, and smoke is expected to clear our area Thursday as the high pressure ridge shifts.

Last year was Canada's most destructive wildfire season on record, burning an area larger than Greece -- seven times larger than a normal Canadian wildfire season. Climate scientists have found that warmer temperatures brought on by manmade climate change are drying vegetation and making Canadian fires worse .