Bad Air Days in Codington County, South Dakota: 3 a Year
3 bad air days a year
About the middle of monitored US counties. Ranked 406 of 996 monitored counties, where 1 is worst.
What makes them bad: a mix of particles and ozone (59% particle days).
Which months to watch
- J
- F
- M
- A
- M
- J
- J
- A
- S
- O
- N
- D
Most bad days here fall in June and July and May and August. Averaged over 2016 to 2025.
Is a purifier worth it here?
- Bad air days are rare here. A standard furnace filter is enough; no purifier needed for outdoor air.
- On the odd bad day, check AirNow and keep windows shut.
Better or worse than it was
In 2000 to 2009 this county averaged under 1 bad days a year; in 2016 to 2025, 3. It has got worse. The worst recent year was 2023, with 13 bad days on 363 monitored days.
| Date | AQI | Main pollutant |
|---|---|---|
| 2021-07-29 | 271 | PM2.5 |
| 2021-07-30 | 181 | PM2.5 |
| 2023-05-18 | 164 | PM2.5 |
| 2025-06-01 | 154 | PM2.5 |
| 2021-07-31 | 153 | PM2.5 |
An ordinary day in Codington
Across 3,639 monitored days from 2016 to 2025, the air in Codington County rated Good on 75% of them, close to the 72% typical of monitored counties, and Moderate on 25%. The median day sat at AQI 38; one day in ten went above 60.
The pollutant setting the AQI on an ordinary day here:
- fine particles (PM2.5)64%2,347 days
- ozone23%844 days
- coarse dust (PM10)12%448 days
Year by year
| Year | Days monitored | Good | Moderate | Over 100 | Over 150 | Median AQI | Highest AQI |
|---|---|---|---|---|---|---|---|
| 2025* | 363 | 283 | 76 | 4 | 1 | 35 | 154 |
| 2024 | 361 | 269 | 91 | 1 | 0 | 37 | 102 |
| 2023 | 363 | 215 | 135 | 13 | 1 | 45 | 164 |
| 2022 | 365 | 285 | 79 | 1 | 0 | 41 | 101 |
| 2021 | 365 | 246 | 113 | 6 | 3 | 43 | 271 |
| 2020 | 366 | 293 | 72 | 1 | 0 | 38 | 101 |
| 2019 | 361 | 295 | 66 | 0 | 0 | 32 | 83 |
| 2018 | 365 | 260 | 104 | 1 | 0 | 39 | 103 |
| 2017 | 364 | 276 | 88 | 0 | 0 | 39 | 82 |
| 2016 | 366 | 295 | 71 | 0 | 0 | 28 | 73 |
| 2015 | 356 | 276 | 79 | 1 | 0 | 34 | 138 |
| 2014 | 365 | 327 | 38 | 0 | 0 | 23 | 87 |
| 2013 | 361 | 198 | 163 | 0 | 0 | 48 | 84 |
| 2012 | 357 | 151 | 206 | 0 | 0 | 52 | 92 |
| 2011 | 356 | 311 | 44 | 1 | 0 | 20 | 102 |
| 2010 | 364 | 310 | 54 | 0 | 0 | 23 | 99 |
*2025 may be a partial year in EPA's file.
Nearby counties on file
- Clay County6/yr
- Minnehaha County5/yr
- Pennington County4/yr
- Brown County3/yr
- Brookings County3/yr
- Custer 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.