Illinois faces another day of poor air quality as wildfire smoke, heat combine

Air quality alerts remain in effect through Wednesday evening as temperatures approach the mid-90s and Canadian wildfire smoke adds haze across northern Illinois

Northern Illinois residents will have to contend with another day of hot, muggy weather and poor air quality Wednesday as elevated ozone levels and Canadian wildfire smoke combine to create unhealthy conditions across much of the region. The National Weather Service said poor air quality is expected to continue through at least Wednesday evening across portions of northeast Illinois and northwest Indiana. Forecasters warned that surface smoke from Canadian wildfires could increase later in the week, potentially extending the air quality concerns.

The Illinois Environmental Protection Agency has declared an Air Pollution Action Day, while Indiana officials also have issued an Air Quality Action Day for northwest Indiana. The primary concern is elevated ground-level ozone, which can make it harder to breathe, especially for children, older adults and people with asthma or other respiratory conditions. The National Weather Service advises everyone to shorten outdoor activities and reduce strenuous exercise, while sensitive groups should spend less time outside and watch for symptoms such as coughing or shortness of breath.

The poor air quality comes as a strong area of high pressure keeps hot and humid weather locked over the Midwest. Temperatures climbed into the mid- to upper 90s Tuesday afternoon, with heat index values reaching about 100 degrees across inland areas. Similar conditions are expected Wednesday, with highs again reaching the mid-90s away from Lake Michigan.

Communities along the immediate lakeshore should remain somewhat cooler, with highs in the upper 80s as a lake breeze develops. Forecasters expect some haze on Wednesday as wildfire smoke drifts into the region from the east. While the smoke and a few afternoon clouds could trim temperatures by a degree or two in some locations, it won’t provide much relief from the heat.

Officials are encouraging residents to stay hydrated, limit outdoor activity during the hottest part of the day and check on vulnerable neighbors. The weather pattern begins to shift later this week. Thursday should remain hot, with highs in the lower 90s, before increasing chances for showers and thunderstorms arrive Friday afternoon and continue at times through the weekend.