# Counties in Iowa by median Air Quality Index (US EPA), 2016

All 19 values come from U.S. Environmental Protection Agency for 2016, so the places are comparable. 7 counties have no value for that period and are not ranked.

- Indicator id: `aqi_median`
- Unit: index
- Definition: Median of the daily Air Quality Index (AQI) values of a US county over the days of the year with an AQI, from the EPA AirData annual summaries. The daily county AQI is the highest AQI among the monitors and pollutants reported that day (ozone, PM2.5, PM10, carbon monoxide and nitrogen dioxide). Lower is cleaner: 0 to 50 is good, 51 to 100 moderate and above 100 unhealthy for sensitive groups.
- Source: U.S. Environmental Protection Agency, EPA AirData annual AQI by county: median daily AQI (https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual)
- Publisher page: https://invokely.ai/en/publishers/environmental-protection-agency
- Retrieved: 2026-10-12
- Citation: U.S. Environmental Protection Agency, Air Quality System, AirData. EPA AirData annual AQI by county: median daily AQI. https://aqs.epa.gov/aqsweb/airdata/download_files.html#Annual. Retrieved 2026-10-12.
- Web page: https://invokely.ai/rankings/median-air-quality-index/iowa-counties

| Rank | Place | index |
|---:|---|---:|
| 1 | Scott County | 60 |
| 2 | Clinton County | 57 |
| 3 | Black Hawk County | 51 |
| 3 | Van Buren County | 51 |
| 5 | Muscatine County | 49 |
| 6 | Linn County | 47 |
| 7 | Johnson County | 44 |
| 7 | Montgomery County | 44 |
| 7 | Polk County | 44 |
| 10 | Lee County | 42 |
| 10 | Palo Alto County | 42 |
| 12 | Harrison County | 37 |
| 13 | Pottawattamie County | 36 |
| 13 | Woodbury County | 36 |
| 15 | Story County | 35 |
| 16 | Bremer County | 33 |
| 16 | Warren County | 33 |
| 18 | Delaware County | 31 |
| 19 | Cerro Gordo County | 15 |