The Indiana Department of Environmental Management (IDEM) has forecast an Air Quality Action Day (AQAD) for Thursday, June 4, 2026, as ozone levels are expected to reach the Unhealthy for Sensitive Groups (Orange) category across much of the state.
According to IDEM, warm, dry, and sunny weather conditions are expected to continue throughout the day, with temperatures climbing into the mid-80s or higher. Ozone concentrations have steadily increased over the past several days as Indiana has remained under the same air mass, leading forecasters to anticipate unhealthy ozone levels for sensitive populations.
An Action Day Alert has been issued for the following counties: Bartholomew, Boone, Brown, Clinton, Decatur, Delaware, Fayette, Franklin, Hamilton, Hancock, Hendricks, Henry, Howard, Johnson, Madison, Marion, Monroe, Morgan, Randolph, Rush, Shelby, Tipton, Union, Wayne, and surrounding areas.
People most affected by elevated ozone levels include children, older adults, and individuals with asthma, heart disease, or other respiratory conditions. These groups are encouraged to limit prolonged outdoor activity, especially during the afternoon and evening hours when ozone concentrations are typically highest.
Hoosiers can visit SmogWatch.IN.gov to view current air quality conditions, access county-specific forecasts, learn more about Air Quality Action Days, and sign up for air quality alerts.
Air Quality Action Days remain in effect from midnight until 11:59 p.m. on the designated date. Residents should also be aware that some municipalities enforce additional open burning restrictions during AQADs.
IDEM notes that its forecasts are based on data collected from air quality monitoring stations located throughout Indiana. Additional information about air quality and ozone forecasts is available at SmogWatch.IN.gov.