Air Quality Rankings for South Dakota 2026
South Dakota has 10 cities with EPA air quality data. Hughes, South Dakota has the cleanest air with a 5-year average AQI of 13. Custer, South Dakota has the highest AQI at 41.
| # | City | 5yr Avg AQI | Current AQI | Worst Pollutant | Trend | Grade |
|---|---|---|---|---|---|---|
| 1 | Hughes, South Dakota | 13 | 14 | PM2.5 | Improving | A |
| 2 | Brown, South Dakota | 26 | 29 | PM2.5 | Improving | B |
| 3 | Pennington, South Dakota | 38 | 45 | PM2.5 | Stable | C |
| 4 | Meade, South Dakota | 39 | 43 | Ozone | Worsening | C |
| 5 | Jackson, South Dakota | 39 | 43 | Ozone | Stable | B |
| 6 | Minnehaha, South Dakota | 39 | 44 | Ozone | Improving | B |
| 7 | Brookings, South Dakota | 40 | 42 | Ozone | Worsening | C |
| 8 | Codington, South Dakota | 40 | 45 | PM2.5 | Worsening | D |
| 9 | Union, South Dakota | 40 | 44 | Ozone | Stable | B |
| 10 | Custer, South Dakota | 41 | 43 | Ozone | Stable | C |
Air quality data for South Dakota is sourced from the EPA Air Quality System (AQS), which monitors outdoor air quality at thousands of stations nationwide.
Frequently Asked Questions
Hughes, South Dakota has the best air quality in South Dakota with a 5-year average AQI of 13 and a grade of A.
South Dakota has 10 cities with EPA air quality monitoring data in our database, covering multiple years of AQI measurements.
The Air Quality Index (AQI) measures five major pollutants: ground-level ozone, particulate matter (PM2.5 and PM10), carbon monoxide, sulfur dioxide, and nitrogen dioxide. Lower AQI values indicate cleaner air — 0-50 is "Good," while 150+ is "Unhealthy."
Cities ranked by 5-year average AQI (lower is better). Grades factor in average AQI, trend direction, unhealthy days, and dominant pollutant.