SmogRank / World / United States / Illinois / June 2023
Most polluted cities in Illinois, United States, June 2023
20 cities in Illinois, United States ranked by their average PM2.5 over the 30 days. Worst: Rockford at 32.9 µg/m³, #60 of 1,549 cities in the world. Cleanest: Granite City at 17.7. 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.
- 1Rockford 20%
- 2Winthrop Harbor 17%
- 3Bloomington 13%
- 4Moline 13%
- 5Naperville 10%
- 6Joliet 10%
- 7Cary 10%
- 7Des Plaines 10%
- 9Calumet City 10%
- 10Decatur 10%
- 11Braidwood 10%
- 12Northbrook 10%
- 13Franklin Park 10%
- 14Chicago 10%
- 15Oak Lawn 10%
- 16Savoy 7%
- 17East Saint Louis 7%
- 18Springfield 7%
- 19Jerseyville 7%
- 20Granite City 4%
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
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SmogRank, most polluted cities in Illinois, United States, PM2.5, June 2023, smogrank.com/us/region/illinois/history/2023-06 (accessed 7 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.