SmogRank / World / United States / Illinois / July 2026
Most polluted cities in Illinois, United States, July 2026
31 cities in Illinois, United States ranked by their average PM2.5 over the 31 days. Worst: Elgin at 30.8 µg/m³, #129 of 2,751 cities in the world. Cleanest: Jerseyville at 10.4. 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.
- 1Elmwood Parklow-cost sensors 19%
- 2Winthrop Harbor 17%
- 3Elgin 16%
- 4Northbrook 16%
- 5Lincolnwood 14%
- 6Calumet City 14%
- 7Oak Lawn 13%
- 8Franklin Park 13%
- 9Bridgeview 13%
- 10Naperville 13%
- 11Dolton 13%
- 12Chicago 13%
- 13Brookfield 13%
- 14Rockford 13%
- 15Cary 13%
- 16Des Plaines 13%
- 17Warrenville 13%
- 18Joliet 13%
- 19Braidwood 13%
- 20Peoria 6%
- 21Decatur 6%
- 22Champaign 6%
- 23Springfield 6%
- 24Moline 6%
- 25Savoy 6%
- 26Bloomington 6%
- 27Upper Alton 3%
- 28Granite City 3%
- 28Wood River 3%
- 30East Saint Louis 3%
- 31Jerseyville 3%
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, July 2026 · All cities in United States, July 2026 · Illinois now
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SmogRank, most polluted cities in Illinois, United States, PM2.5, July 2026, smogrank.com/us/region/illinois/history/2026-07 (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.