An air quality alert in the Chicago area has been extended for another day as Canadian wildfire smoke continues to plague the area.
According to the National Weather Service, McHenry, Lake, Kane, DuPage, Kendall, Grundy, Cook and Will counties will remain under the alert through at least Thursday night, continuing a week-long trend of poor air quality in the region.
In response, the Illinois Environmental Protection Agency has declared an Air Pollution Action Day for Thursday.
According to the alert, active children and adults, especially people with pulmonary or respiratory disease such as asthma, should limit prolonged outdoor activity.
While air quality has improved in some locations, it is expected to worsen in the Chicago area Wednesday and into Thursday, sliding back into the “unhealthy for sensitive groups” category, according to AirNow.
Wildfire smoke from Canada is still impacting the area, but elevated ground-level ozone is also expected to be a factor, according to officials.
That ozone, according to the EPA, forms at ground level when pollutants emitted by vehicles, power plants and other sources interacts with sunlight, degrading air quality in urban areas. Wind can then blow those pollutants into nearby areas, causing the impact to be more wide-ranging.
So when will the Chicago area see relief from the poor air quality that’s plagued the region for a week?
As things stand, a temperature inversion remains firmly in place over the area, with a mass of warm air currently hovering over a mass of cooler air near the surface, according to the NBC 5 Storm Team.
That layer could be broken by the potential for strong-to-severe thunderstorms, which could impact the Chicago area on Thursday, according to forecast models.
According to the Storm Prediction Center, most of Illinois is at a “marginal risk” for severe storms, with the main threats being heavy rain and gusty winds.
Such an event would cause the inversion layer to break up, and would allow the remaining wildfire smoke and trapped ground-level ozone to escape, improving Chicago’s air quality in the process.
If that cap remains in place, air quality concerns could persist until it breaks up, with several additional chances for showers and storms in coming days, according to forecast models.
(Except for the headline, this story has not been edited by PostX News and is published from a syndicated feed.)
