Air quality · Missouri
Air quality in Missouri
Across the 2 Missouri ZIPs with EPA county air-quality data, the median day is Good in all 2 (median AQI 37–47). 2 days across those counties reached Unhealthy or worse in 2025. This is a 2025 county annual summary, not a live reading.
Last verified 2026-09-24 · methodology
Air quality by ZIP code in Missouri
EPA's 2025 annual summary for each ZIP's county. Median AQI is the typical day; lower is cleaner.
| ZIP | Median AQI | Good days | Unhealthy or worse |
|---|---|---|---|
| 64106Kansas CityJackson County | 47 Good | 209 of 365 | 2 |
| 63101St. LouisSt. Louis (city) | No data | ||
| 65201Columbia (MO)Boone County | 37 Good | 231 of 248 | 0 |
County-level figures from EPA Air Quality System (AQS), annual county summary, joined to each ZIP by county. None of them is a measurement at a specific address.
What lands here
Pages show the 2025 median AQI category (Good, Moderate, Unhealthy for Sensitive Groups, Unhealthy, Very Unhealthy, Hazardous) for the ZIP's county, plus the year's max/90th-percentile AQI and day-count breakdown by category.
Source & refresh
EPA Air Quality System (AQS), annual county summary. Refreshed annual (epa aqs publication). Primary source →
Missouri top concern
Radon, flooding (Missouri/Mississippi), tornadoes
Missouri has Zone 1 radon across most of the state. Major river FEMA AE zones along the Missouri + Mississippi affect St. Louis, Hannibal, Cape Girardeau. Tornado risk peaks April-May.
See Missouri state page for the full state-level rollup across all 12 dimensions.
Read more on air quality
Editorial deep-dives explaining the source data, its limits, and how to read it.
EPA AQI categories explained — what 0–50 Good through 301–500 Hazardous mean
Plain-English guide to the six EPA Air Quality Index categories: 0–50 Good, 51–100 Moderate, 101–150 Unhealthy for Sensitive Groups, 151–200 Unhealthy, 201–300 Very Unhealthy, 301–500 Hazardous — what each level means and who is at risk.
AQI explained — what 50, 100, 150 actually mean for your lungs
Plain-English guide to the EPA Air Quality Index (AQI) and the 6 categories from Good to Hazardous. When to take precautions and which pollutants matter.
Wildfire Hazard Potential — what the USFS scale means and how to defend your home
Plain-English guide to the USDA Forest Service's Wildfire Hazard Potential 1–5 scale, how to read your community's risk, and concrete home-defense measures.
AirNow + wildfire smoke — when AQI is a real-time tool
How EPA AirNow handles real-time wildfire smoke, what the colors mean during fire season, and where AirNow leaves gaps you should know about.