SmogRank / World / North America / United States / Illinois

Most polluted cities in Illinois, United States

31 measured cities, this year; 31 above the WHO annual guideline. Worst: Elmwood Park at 13.0 µg/m³, #661 in the world.

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.

Michigan: 21 measured citiesIowa: 9 measured citiesMissouri: 10 measured citiesWisconsin: 10 measured citiesIllinois: 31 measured citiesKentucky: 17 measured citiesArkansas: 4 measured citiesTennessee: 14 measured citiesIndiana: 18 measured cities#31 Bloomington: 7.1 µg/m³#30 Savoy: 7.2 µg/m³#29 Braidwood: 7.3 µg/m³#28 Jerseyville: 7.4 µg/m³#26 Springfield: 7.6 µg/m³#27 Moline: 7.6 µg/m³#25 Champaign: 7.7 µg/m³#24 Decatur: 8.2 µg/m³#23 Winthrop Harbor: 8.3 µg/m³#21 East Saint Louis: 8.5 µg/m³#22 Cary: 8.5 µg/m³#20 Joliet: 8.6 µg/m³#19 Warrenville: 8.8 µg/m³#18 Upper Alton: 9.0 µg/m³#17 Wood River: 9.1 µg/m³#14 Des Plaines: 9.3 µg/m³#15 Northbrook: 9.3 µg/m³#16 Peoria: 9.3 µg/m³#13 Rockford: 9.4 µg/m³#12 Naperville: 9.5 µg/m³#11 Granite City: 9.7 µg/m³#10 Chicago: 9.8 µg/m³#7 Calumet City: 10.1 µg/m³#8 Lincolnwood: 10.1 µg/m³#9 Oak Lawn: 10.1 µg/m³#6 Elgin: 10.8 µg/m³#4 Bridgeview: 10.9 µg/m³#5 Dolton: 10.9 µg/m³#3 Brookfield: 11.0 µg/m³#2 Franklin Park: 11.1 µg/m³#1 Elmwood Park: 13.0 µg/m³
Each dot is a measured city, coloured by its PM2.5; tap a dot to open the city.
← Elmwood Park 3% 3%0
Every measured city in Illinois, United States, one column each, ranked by unhealthy days: height is the share of its measured days that were unhealthy, colour its average. Point at it to read a city; tap to open it.
  1. 1Elmwood Parklow-cost sensors 3%
  2. 2Elgin 2%
  3. 3Winthrop Harbor 2%
  4. 4Northbrook 2%
  5. 5Dolton 1%
  6. 6Bridgeview 1%
  7. 7Calumet City 1%
  8. 7Oak Lawn 1%
  9. 9Lincolnwood 1%
  10. 10Braidwood 1%
  11. 11Brookfield 1%
  12. 12Des Plaines 1%
  13. 13Joliet 1%
  14. 14Franklin Park 1%
  15. 15Chicago 1%
  16. 16Naperville 1%
  17. 17Rockford 1%
  18. 18Warrenville 1%
  19. 19Cary 1%
  20. 20Champaignlast full day 30 Sept 1%
  21. 21Peoria 1%
  22. 22Savoy 1%
  23. 23Springfield 1%
  24. 24Decatur 1%
  25. 25Moline 1%
  26. 26Bloomington 1%
  27. 27Jerseyville 0%
  28. 28Wood River 0%
  29. 29Upper Alton 0%
  30. 30Granite City 0%
  31. 31East Saint Louis 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.

Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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

Estimated: cities without a monitor

Illinois cities we can't measure, with model estimates for the last 7 days. Listed by population, not ranked: estimates aren't precise enough to rank. Model estimates from the Copernicus Atmosphere Monitoring Service (CAMS), adjusted to measured cities nearby where there are any. Adjusted, a single day lands within ×1.5 of what a monitor would read about two times in three; unadjusted, it can be off by half or double. Treat them as a guide, not a measurement.

City7-day estimateBand
Aurora≈ 7 µg/m³Good
North Peoria≈ 7 µg/m³Good
Waukegan≈ 6 µg/m³Good
Cicero≈ 8 µg/m³Good
Arlington Heights≈ 8 µg/m³Good
Schaumburg≈ 8 µg/m³Good
Bolingbrook≈ 7 µg/m³Good
Palatine≈ 8 µg/m³Good
Orland Park≈ 7 µg/m³Good
Tinley Park≈ 7 µg/m³Good
Berwyn≈ 8 µg/m³Good
Mount Prospect≈ 8 µg/m³Good
Normal≈ 5 µg/m³Good
Wheaton≈ 8 µg/m³Good
Oak Park≈ 8 µg/m³Good
Hoffman Estates≈ 8 µg/m³Good
Downers Grove≈ 8 µg/m³Good
Glenview≈ 7 µg/m³Good
Elmhurst≈ 8 µg/m³Good
Lombard≈ 8 µg/m³Good
DeKalb≈ 6 µg/m³Good
Plainfield≈ 7 µg/m³Good
Urbana≈ 6 µg/m³Good
Belleville≈ 9 µg/m³Good
Bartlett≈ 8 µg/m³Good
Buffalo Grove≈ 8 µg/m³Good
Quincy≈ 6 µg/m³Good
Streamwood≈ 8 µg/m³Good
Crystal Lake≈ 6 µg/m³Good
Carol Stream≈ 8 µg/m³Good
Romeoville≈ 7 µg/m³Good
Rock Island≈ 7 µg/m³Good
Carpentersville≈ 7 µg/m³Good
Hanover Park≈ 8 µg/m³Good
Wheeling≈ 8 µg/m³Good
Addison≈ 8 µg/m³Good
Glendale Heights≈ 8 µg/m³Good
Oswego≈ 7 µg/m³Good
Woodridge≈ 7 µg/m³Good
Elk Grove Village≈ 8 µg/m³Good

Bad-air episodes in Illinois

Times when many cities around here had PM2.5 at twice their usual or more on the same days.

Use this board

SmogRank, most polluted cities in Illinois, United States, PM2.5, this year to 6 Oct 2026, 22:00 UTC, smogrank.com/us/region/illinois?w=year.

Download top 10 (PNG)

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.

Updated 2026-10-06 22:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index.