SmogRank / World / United States / Illinois / October 2024
Most polluted cities in Illinois, United States, October 2024
26 cities in Illinois, United States ranked by their average PM2.5 over the 31 days. Worst: Granite City at 10.7 µg/m³, #442 of 1,966 cities in the world. Cleanest: Winthrop Harbor at 6.2. A city needs measurements on 70% of the days to be ranked.
Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.
- 1Granite City 0%
- 2Wood River 0%
- 3Upper Alton 0%
- 4East Saint Louis 0%
- 4Elmwood Parklow-cost sensors 0%
- 6Brookfield 0%
- 7Elgin 0%
- 8Decatur 0%
- 9Peoria 0%
- 10Cary 0%
- 11Naperville 0%
- 11Rockford 0%
- 13Chicago 0%
- 13Joliet 0%
- 15Calumet City 0%
- 16Springfield 0%
- 17Jerseyville 0%
- 17Champaign 0%
- 17Moline 0%
- 20Bloomington 0%
- 20Franklin Park 0%
- 22Des Plaines 0%
- 23Northbrook 0%
- 24Savoy 0%
- 25Braidwood 0%
- 26Winthrop Harbor 0%
Low-cost sensors: consumer units, counted only in cities with no government-grade monitor; they read close to reference monitors on the whole, but 15 to 25% high in humid air. How we use them.
The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
All cities in the world, October 2024 · All cities in United States, October 2024 · Illinois now
Use this board
SmogRank, most polluted cities in Illinois, United States, PM2.5, October 2024, smogrank.com/us/region/illinois/history/2024-10 (accessed 6 Oct 2026).
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.