Air Quality Affected by Particulate Matter and Ozone
INDIANAPOLIS – The Indiana Department of Environmental Management (IDEM) has forecast an Air Quality Action Day (AQAD) for Thursday, July 16, 2026, in three Northern Indiana regions.
Fine particulate matter (PM2.5) levels are expected to be in the Unhealthy range (Red) and ozone levels are expected to be in the Unhealthy for Sensitive Groups range (Orange) in the following areas:
Northwest Indiana, including the cities of: Crown Point, Gary, Hammond, Kentland, LaPorte, Michigan City, Portage, Rensselaer, Valparaiso and all other cities within the area.
North Central Indiana, including the cities of: Elkhart, Goshen, Knox, Logansport, Plymouth, Peru, South Bend, Warsaw, Winamac and all other cities within the area.
Northeast Indiana, including the cities of: Angola, Auburn, Decatur, Fort Wayne, Hartford, Huntington City, LaGrange, Marion, Portland, Wabash and all other cities within the area.
Significant concentrations of wildfire smoke currently behind a front will move into the state from the north tomorrow. This smoke, in addition to the other meteorological factors, such as light winds and recent stagnant conditions, will produce PM2.5 readings into the Unhealthy range for Northwest, North Central, and Northeast Indiana. Ozone levels are expected to reach the Unhealthy for Sensitive Groups range.
For reporting purposes, this AQAD will be attributed to PM2.5.
IDEM forecasted Air Quality Action Days indicate anticipated higher levels of ground-level ozone and fine particulate matter only.
Other factors may affect overall air quality.
Hoosiers can visit SmogWatch.IN.gov to:
View air quality information for all Indiana counties, including a state map of affected counties;
Learn more about Air Quality Action Days and recommended actions;
Learn more about ozone and fine particulate matter; and
Sign up for air quality alerts.
Air Quality Action Days are in effect from midnight to 11:59 p.m. (24 hours) on the specified date. Some municipalities have additional open burning restrictions on AQADs. For more information, go to idem.IN.gov/openburning/laws-and-rules.
