Bad Air Days in Minnehaha County, South Dakota: 5 a Year
5 bad air days a year
More bad air days than three quarters of monitored counties. Ranked 248 of 996 monitored counties, where 1 is worst.
What makes them bad: mostly ozone: summer smog (33% particle days).
The bad-air season here
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in June and May and July. Averaged over 2016 to 2025.
Is a purifier worth it here?
- Ozone drives many bad days here. Purifiers and filters do not remove ozone, so do not buy one for that. Ozone peaks on hot afternoons: exercise outside in the morning.
The worst days on file
In 2000 to 2009 this county averaged 1 bad days a year; in 2016 to 2025, 5. It has got worse. The worst recent year was 2023, with 27 bad days on 365 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2021-07-30 | 193 | PM2.5 |
| 2023-05-18 | 181 | PM2.5 |
| 2021-07-29 | 172 | PM2.5 |
| 2023-07-15 | 157 | PM2.5 |
| 2023-07-16 | 157 | PM2.5 |
An ordinary day in Minnehaha
Across 3,635 monitored days from 2016 to 2025, the air in Minnehaha County rated Good on 78% of them, more often than the 72% typical of monitored counties, and Moderate on 21%. The median day sat at AQI 39; one day in ten went above 62.
The pollutant setting the AQI on an ordinary day here:
- ozone63%2,276 days
- fine particles (PM2.5)33%1,216 days
- coarse dust (PM10)2%88 days
- nitrogen dioxide2%55 days
Every recent year on file
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 364 | 294 | 66 | 4 | 0 | 36 | 125 |
| 2024 | 365 | 297 | 66 | 2 | 0 | 34 | 145 |
| 2023 | 365 | 235 | 103 | 27 | 4 | 44 | 181 |
| 2022 | 365 | 300 | 64 | 1 | 0 | 39 | 105 |
| 2021 | 349 | 266 | 78 | 5 | 2 | 39 | 193 |
| 2020 | 366 | 298 | 68 | 0 | 0 | 38 | 90 |
| 2019 | 365 | 301 | 63 | 1 | 0 | 37 | 105 |
| 2018 | 365 | 275 | 87 | 3 | 0 | 40 | 115 |
| 2017 | 365 | 287 | 78 | 0 | 0 | 38 | 97 |
| 2016 | 366 | 269 | 95 | 2 | 0 | 42 | 105 |
| 2015 | 365 | 207 | 155 | 3 | 0 | 47 | 124 |
| 2014 | 363 | 253 | 108 | 2 | 0 | 43 | 105 |
| 2013 | 365 | 206 | 159 | 0 | 0 | 48 | 99 |
| 2012 | 366 | 213 | 145 | 8 | 1 | 46 | 170 |
| 2011 | 365 | 217 | 147 | 1 | 0 | 46 | 105 |
| 2010 | 365 | 190 | 174 | 1 | 0 | 49 | 122 |
*2025 may be a partial year in EPA's file.
Nearby counties on file
- Clay County6/yr
- Pennington County4/yr
- Brown County3/yr
- Brookings County3/yr
- Custer County3/yr
- Codington County3/yr
- Jackson County2/yr
- Union County2/yr
How this is counted
A bad air day is a day the county's daily AQI from EPA AirData went above 100, the level where EPA tells children, older adults and people with asthma or heart disease to cut back outdoors. Monitors do not run every day, so yearly counts are scaled to 365 days. This is the record, not today's air: for that, check AirNow. More on the method in how the county numbers are made, on the AQI 100 line in what counts as a bad air day, and on why a purifier does not touch ozone in smoke vs ozone.