SmogRank / World / North America / United States / Missouri
Most polluted cities in Missouri, United States
10 measured cities, last 30 days; 0 above the WHO 24-hour guideline. Worst: St. Louis at 7.9 µg/m³, #1,001 in the world.
About 0 people in this city breathed unhealthy air on an average day over the last 30 days.
Ranked by people: each city's population times its share of unhealthy days, those with a daily mean over 35.4 µg/m³ (US AQI 101+). That is how many people living there breathed unhealthy air on an average day. Only cities measured at 2 or more places at least 3 km apart are ranked: one monitor shouldn't speak for a whole city. Population is the city itself, not its wider metro area.
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
Missouri 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.
| City | 7-day estimate |
|---|---|
| Independence | ≈ 7 µg/m³ |
| Lee's Summit | ≈ 6 µg/m³ |
| O'Fallon | ≈ 9 µg/m³ |
| Saint Charles | ≈ 11 µg/m³ |
| Blue Springs | ≈ 7 µg/m³ |
| Saint Peters | ≈ 9 µg/m³ |
| Florissant | ≈ 11 µg/m³ |
| Joplin | ≈ 5 µg/m³ |
| Chesterfield | ≈ 11 µg/m³ |
| Jefferson City | ≈ 6 µg/m³ |
| Cape Girardeau | ≈ 7 µg/m³ |
| Oakville | ≈ 11 µg/m³ |
| Wildwood | ≈ 9 µg/m³ |
| Wentzville | ≈ 9 µg/m³ |
| Ballwin | ≈ 11 µg/m³ |
| Liberty | ≈ 7 µg/m³ |
| Raytown | ≈ 7 µg/m³ |
| Mehlville | ≈ 11 µg/m³ |
| Kirkwood | ≈ 11 µg/m³ |
| Maryland Heights | ≈ 11 µg/m³ |
| Gladstone | ≈ 7 µg/m³ |
| Hazelwood | ≈ 11 µg/m³ |
| Grandview | ≈ 6 µg/m³ |
| Webster Groves | ≈ 11 µg/m³ |
| Sedalia | ≈ 4 µg/m³ |
| Ferguson | ≈ 11 µg/m³ |
| Nixa | ≈ 4 µg/m³ |
| Affton | ≈ 11 µg/m³ |
| Rolla | ≈ 6 µg/m³ |
| Warrensburg | ≈ 4 µg/m³ |
| Spanish Lake | ≈ 11 µg/m³ |
| Old Jamestown | ≈ 11 µg/m³ |
| Ozark | ≈ 4 µg/m³ |
| Creve Coeur | ≈ 11 µg/m³ |
| Manchester | ≈ 11 µg/m³ |
| Farmington | ≈ 6 µg/m³ |
| Hannibal | ≈ 6 µg/m³ |
| Kirksville | ≈ 4 µg/m³ |
| Poplar Bluff | ≈ 6 µg/m³ |
| Sikeston | ≈ 6 µg/m³ |
Bad-air episodes in Missouri
- Northern United States and Canada, July 202614 to 21 July 2026, 8 days327 cities548 µg/m³peak, Superior
- Northern United States, July 20264 to 5 July 2026, 2 days10 cities85 µg/m³peak, Omaha
- North-eastern United States and Canada, 29 July to 9 August 202512 days292 cities112 µg/m³peak, Marquette
- North-eastern United States, July 20254 to 5 July 2025, 2 days68 cities74 µg/m³peak, Lincolnwood
- Northern United States and Canada, June 202510 to 14 June 2025, 5 days134 cities71 µg/m³peak, Wilmington
- Northern United States and Canada, May and June 202531 May to 9 June 2025, 10 days247 cities116 µg/m³peak, Nepean
Times when many cities around here had PM2.5 at twice their usual or more on the same days.
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SmogRank, most polluted cities in Missouri, United States, PM2.5, last 30 days to 6 Oct 2026, 22:00 UTC, smogrank.com/us/region/missouri?w=30d.
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.