INDIANAPOLIS–The Indianapolis Office of Sustainability issued a Knozone Advisory today for Wednesday evening through Thursday morning as fine particulate matter levels are expected to reach unhealthy concentrations.
The advisory runs from 6:00 p.m. Wednesday, October 28, through 10:00 a.m. Thursday, October 29. Hourly PM2.5 levels are expected to reach the Unhealthy (Red) to Unhealthy for Sensitive Groups (Orange) Air Quality Index range during this period.
This marks the second Knozone Advisory declared in 2026.
Who’s at Risk?
Children, older adults, pregnant people, outdoor workers, and anyone with asthma, COPD, emphysema, heart disease or similar conditions face greater risk during periods of poor air quality. Nearly 1 in 5 Marion County residents falls into a higher-risk category for severe symptoms.
The Office of Sustainability recommends sensitive groups remain indoors as much as possible during the advisory period.
What You Can Do to Stay Safe
City officials recommend several steps to reduce exposure to outdoor air during the advisory:
- Stay indoors with windows closed
- Run an air conditioner if available
- Use a high-efficiency particulate air (HEPA) purifier
- In vehicles, use the “recirculate air” function and keep windows closed
- Avoid activities that degrade indoor air quality, including burning candles and vacuuming
Reduce Your Contribution to Poor Air Quality
Residents can help improve air quality by taking these actions:
Never burn trash, furniture, leaves or grass clippings. Burning these items is illegal in Marion County and punishable by fines up to $2,500. Report illegal open burning through the RequestIndy mobile app or website, or call the Mayor’s Action Center at 317-327-4622. For emergencies, call 911.
Avoid campfires, bonfires and barbecues until air quality returns to healthy levels. Rules and regulations for open burning are available on the Department of Business and Neighborhood Services website at indy.gov/BNS.
Understanding Knozone Advisories
A Knozone Advisory differs from a Knozone Action Day. The Office of Sustainability issues an advisory when overall daily average PM2.5 concentrations may not warrant a full action day over 24 hours, but hourly values may reach Unhealthy for Sensitive Groups levels or higher for several hours.
Fine particulate matter, or PM2.5, refers to microscopic particles in the air — including dust and smoke — that can be inhaled into the lungs and cause damage. These particles can originate from local sources or travel from wildfires and dust clouds thousands of miles away.
