SmogRank / World / United States / Illinois / April 2023
Most polluted cities in Illinois, United States, April 2023
18 cities in Illinois, United States ranked by their average PM2.5 over the 30 days. Worst: Oak Lawn at 10.0 µg/m³, #426 of 1,567 cities in the world. Cleanest: Cary at 7.0. A city needs measurements on 70% of the days to be ranked.
OpenAQ's archive, where our readings come from, has almost none for 3 of these 30 days. Cities in the United States and Europe have them from the EPA's and the European Environment Agency's own records of the same monitors; elsewhere a city's average is over its other days. Why.
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.
- 1Oak Lawn 0%
- 2Calumet City 0%
- 3Naperville 0%
- 4East Saint Louis 0%
- 5Joliet 0%
- 6Rockford 0%
- 7Moline 0%
- 8Springfield 0%
- 8Bloomington 0%
- 8Braidwood 0%
- 8Franklin Park 0%
- 12Des Plaines 0%
- 13Jerseyville 0%
- 13Chicago 0%
- 13Winthrop Harbor 0%
- 16Northbrook 0%
- 17Savoy 0%
- 18Cary 0%
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, April 2023 · All cities in United States, April 2023 · Illinois now
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SmogRank, most polluted cities in Illinois, United States, PM2.5, April 2023, smogrank.com/us/region/illinois/history/2023-04 (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.