Air Quality Rankings for Missouri (2026)
Missouri has 21 cities tracked by EPA air-quality monitors, with a state-wide 5-year median AQI of 41 — roughly matching the national average of AQI 41. Taney, Missouri ranks #1 with the cleanest air (AQI 26, Grade A), while St. Louis City, Missouri sits at the bottom (AQI 55, Grade C).
How Missouri Compares
Missouri has 21 cities tracked by EPA air-quality monitors, with a state-wide 5-year median AQI of 41 — roughly matching the national average of AQI 41. Taney, Missouri ranks #1 with the cleanest air (AQI 26, Grade A), while St. Louis City, Missouri sits at the bottom (AQI 55, Grade C). The rankings below are computed from the EPA Air Quality System (AQS), which aggregates daily AQI readings from federally certified monitors into annual averages. Cities are sorted by 5-year median AQI (lowest = cleanest = #1). The 5-year window smooths out year-to-year volatility from weather and wildfire events.
Air quality across Missouri has held roughly steady over the past decade — 8 cities improving, 8 worsening, and 5 stable. That stability makes the state-average ranking a reliable signal of what residents can expect over time.
The dominant pollutant across 11 of 21 Missouri cities is Ground-Level Ozone. Ground-level ozone forms when sunlight reacts with vehicle and industrial emissions. It is worst on hot, sunny, stagnant summer days and is the leading air quality concern across much of the Sun Belt and California. Other Missouri cities report Fine Particulate Matter (PM2.5) (10) as their dominant concern.
The fastest-improving city in Missouri is Taney, Missouri, with median AQI falling by 1.4 points per year. Steady improvement at that pace usually reflects fleet turnover (older diesels retiring), upwind power-plant retirements, or tighter regional emissions controls.
The city with the steepest decline is Jasper, Missouri, where median AQI is rising by 0.6 points per year. Rapid deterioration in a single city usually points to either wildfire-smoke exposure (in the West) or a new local emissions source — a power plant, port, or freight corridor coming online.
Full Missouri Ranking
| # | City | 5yr Avg AQI | Current AQI | Worst Pollutant | Trend | Grade |
|---|---|---|---|---|---|---|
| 1 | Taney, Missouri | 26 | 29 | PM2.5 | Improving | A |
| 2 | Stoddard, Missouri | 31 | 37 | PM2.5 | Improving | B |
| 3 | Monroe, Missouri | 34 | 38 | Ozone | Stable | B |
| 4 | Boone, Missouri | 38 | 42 | Ozone | Stable | B |
| 5 | Jasper, Missouri | 39 | 42 | Ozone | Worsening | C |
| 6 | Callaway, Missouri | 39 | 43 | Ozone | Stable | B |
| 7 | Sainte Genevieve, Missouri | 40 | 44 | Ozone | Stable | B |
| 8 | Lincoln, Missouri | 40 | 44 | Ozone | Stable | C |
| 9 | Perry, Missouri | 40 | 44 | Ozone | Stable | B |
| 10 | Clinton, Missouri | 40 | 44 | Ozone | Stable | B |
| 11 | Andrew, Missouri | 41 | 43 | Ozone | Stable | C |
| 12 | Cass, Missouri | 41 | 44 | PM2.5 | Improving | B |
| 13 | Clay, Missouri | 41 | 43 | Ozone | Improving | B |
| 14 | Saint Charles, Missouri | 42 | 45 | Ozone | Stable | C |
| 15 | Cedar, Missouri | 42 | 44 | PM2.5 | Stable | C |
| 16 | Jefferson, Missouri | 43 | 44 | PM2.5 | Improving | B |
| 17 | Buchanan, Missouri | 44 | 48 | PM2.5 | Improving | B |
| 18 | Greene, Missouri | 44 | 49 | PM2.5 | Stable | C |
| 19 | Saint Louis, Missouri | 45 | 46 | PM2.5 | Improving | B |
| 20 | Jackson, Missouri | 51 | 52 | PM2.5 | Worsening | C |
| 21 | St. Louis City, Missouri | 55 | 58 | PM2.5 | Stable | C |
Air quality data for Missouri is sourced from the EPA Air Quality System (AQS), which monitors outdoor air quality at thousands of stations nationwide.
Frequently Asked Questions
Taney, Missouri has the best air quality in Missouri with a 5-year average AQI of 26 and a Grade A (82/100). Its dominant pollutant is Fine Particulate Matter (PM2.5) and the long-run trend is improving.
St. Louis City, Missouri has the worst air quality in Missouri with a 5-year average AQI of 55 and a Grade C (53/100). Its dominant pollutant is Fine Particulate Matter (PM2.5).
Missouri has 21 cities with EPA air quality monitoring data, covering 2014-2023 of daily AQI measurements aggregated into annual averages.
Missouri's state-wide 5-year median AQI is 41, roughly matching the national average of AQI 41. Air quality across Missouri has held roughly steady over the past decade — 8 cities improving, 8 worsening, and 5 stable. That stability makes the state-average ranking a reliable signal of what residents can expect over time.
Ground-Level Ozone is the dominant pollutant in 11 of 21 monitored Missouri cities. Ground-level ozone forms when sunlight reacts with vehicle and industrial emissions. It is worst on hot, sunny, stagnant summer days and is the leading air quality concern across much of the Sun Belt and California.
Missouri cities log an average of 3 days per year at "Unhealthy for Sensitive Groups" or worse, based on EPA monitor data over the last five years. Across all 21 Missouri cities tracked, that totals 272 unhealthy days over the period.
Cities ranked by 5-year average AQI (lower is better). Grades factor in average AQI, trend direction, unhealthy days, and dominant pollutant.
The this entity category groups every U.S. air quality and pollution monitoring entity sharing this attribute. The list above is the data; the paragraphs below explain what the grouping means against the broader the EPA Air Quality System (AQS) distribution and how to read the relative rankings within the category.
For readers using this category as a starting point, the per-entity detail pages linked from the table above carry the underlying the EPA Air Quality System (AQS) data in full. The category-level view is the filter; the per-entity pages are the actual answer.
Source: EPA Outdoor Air Quality Data, 2026.