SmogRank / World / United States / Illinois / July 2025
Most polluted cities in Illinois, United States, July 2025
31 cities in Illinois, United States ranked by their average PM2.5 over the 31 days. Worst: Elmwood Park at 20.4 µg/m³, #192 of 2,832 cities in the world. Cleanest: Jerseyville at 8.1. 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 13%
- 2Des Plaines 11%
- 3Lincolnwood 10%
- 4Franklin Park 10%
- 5Dolton 6%
- 6Rockford 6%
- 7Braidwood 4%
- 8Oak Lawn 4%
- 9Bridgeview 3%
- 10Chicago 3%
- 11Brookfield 3%
- 11Cary 3%
- 13Elgin 3%
- 14Naperville 3%
- 15Winthrop Harbor 3%
- 16Joliet 3%
- 17Warrenville 3%
- 18Calumet City 3%
- 19Peoria 3%
- 20Northbrook 3%
- 21Moline 3%
- 22Springfield 3%
- 23Bloomington 3%
- 24East Saint Louis 0%
- 25Wood River 0%
- 26Upper Alton 0%
- 27Granite City 0%
- 28Champaign 0%
- 29Decatur 0%
- 30Savoy 0%
- 31Jerseyville 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, July 2025 · All cities in United States, July 2025 · Illinois now
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SmogRank, most polluted cities in Illinois, United States, PM2.5, July 2025, smogrank.com/us/region/illinois/history/2025-07 (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.