The Indiana Department of Environmental Management announced that Thursday will be another Air Quality Action Day for Northwest Indiana — the fourth this week.
IDEM’s announcement also included Northern Central Indiana — which includes Elkhart, South Bend and Warsaw — and Northeast Indiana — which has Fort Wayne, Marion and Wabash.
According to a Wednesday announcement, fine particulate matter levels will be in the unhealthy range, and ozone levels are expected to be unhealthy for sensitive groups. The U.S. Environmental Protection Agency defines sensitive groups as people with heart or lung diseases, those with diabetes, older adults and children. To reduce ozone and fine particulate matter, IDEM recommends driving less, waiting to refuel until after 7 p.m., avoiding unnecessary fires, and keeping thermostats at around 75 degrees.
Significant concentrations of wildfire smoke from southwestern Ontario wildfires are adding to air quality concerns, according to IDEM, and impact the Great Lakes region.
“This smoke, in addition to the other meteorological factors, such as light winds and recent stagnant conditions, will produce (fine particulate matter) readings into the Unhealthy range for Northwest, North Central, and Northeast Indiana,” the IDEM announcement said.
According to Accuweather, more than 800 wildfires are burning across Canada, and states including Wisconsin, Michigan, New York and Massachusetts have also issued air quality alerts.
In Canada, Toronto reached “very unhealthy” air quality levels with an air quality index of 220, according to Accuweather.
IDEM also declared Air Quality Action Days for Monday, Tuesday and Wednesday in Northwest Indiana. According to the alert for Wednesday, ozone levels were found to be unhealthy for sensitive groups because of “very high temperatures,” sunny skies, relatively low humidity and calm winds that produce stagnant conditions, as well as high surface pressure.
For Monday and Tuesday, IDEM said hot temperatures, sunny skies and light winds were expected through the region, and buildup of pollutants from Lake Michigan, according to Post-Tribune archives.
Prior to this week, IDEM last issued an Air Quality Action Day for July 8 in Northwest Indiana.
According to Post-Tribune archives, IDEM issues Air Quality Action Days when fine particulate matter or ozone levels will be high throughout the day. The department announced at the beginning of May that it will issue local Air Quality Advisories when short-term fine particulate matter levels increase overnight or in early morning.
In 2025, IDEM declared Air Quality Actions Days for ozone levels in Northwest Indiana, according to Post-Tribune archives, and eight were called for high fine particulate matter levels.
