Rain could help improve Chicago-area air quality, but that may not be the case

Chicago-area air quality continued to reach unhealthy levels for yet another day Thursday, but hope that rain may clear the smoke could be misplaced.

Smoke from Canadian wildfires has lowered curtains of haze on broad swaths of Canada and the United States, pushing into Illinois, Indiana and Ohio, and moving into parts of West Virginia. Canadian officials say it is the nation’s worst wildfire season ever and they expect air quality to remain a concern through the summer, as long as the fires continue.

Scattered storms in the Chicago area were seen as potential for redeeming the city's air quality, but according to NBC 5 Storm Team Meteorologist Kevin Jeanes, that may not be the case.

"So it's a very tricky forecast," Jeanes said, adding that wind direction plays an important role in the outcome.

In theory, rain can help improve the air quality in situations like this.

"So sometimes if you get a ton of rain, that could improve the air quality," Jeanes said. "That helps basically, if you have a lot of particulates or particulate matter that's suspended in the air, water could help kind of collect that and keep that out of the air, too, as the rain is coming down."

But that's not always how it happens.

"Other times you get a couple of spotty showers that's not going to do enough," Jeanes said. "And then again, the smoke, it's tough to tell how high up the smoke is in the atmosphere. It might be raining just in the lower 10, 20, 30,000 feet of the atmosphere. But if you have wildfire smoke that's way above that, that might not just dissipate and dilute everything."

Scattered storms made their way into the Chicago area, but several locations avoided the precipitation as the storms dissipated heading into the evening hours. Another wave is still possible, though there remains uncertainty over whether it will reach far enough into the region.

Rain or no rain, however, there is good news.

Jeanes believes the air quality will improve in the coming days.

"So I think it will continue to get better over the next couple of days," he said. "Hopefully, it's a drastic change by [Thursday night] and [Friday] morning."

Forecasts predict Chicago's air quality will in fact improve heading into the weekend.

As of 5 p.m., the PM2.5 sat at 123 for Chicago, putting the city under the lower "unhealthy for sensitive groups" rating, according to AirNow, marking a drop from the "unhealthy" levels seen earlier in the day.

According to AirNow, the poor air quality is expected to gradually improve even more Saturday and Sunday.

So, what are the odds the smoke could return?

“As long as the fires are burning and the smoke is in the atmosphere it is going to be a concern not just for Canadians but Americans as well,” Environment and Climate Change Canada Meteorologist Steven Flisfeder said.

Flisfeder said the smoky, hazy skies will persist unless rainfall provides sufficient help to firefighters in controlling the Canadian blazes.

“Until the fires are out, there’s a risk,” Jackson said. “If there’s any north component to the wind, there’s a chance it’ll be smoky.”

You can check the real-time air quality in your area using the AirNow map here. The numbers are updated every hour and the site also includes a forecast for the day ahead. The map pulls in measurements from a network of air monitoring stations across the country.