Median AQI
33
Good
South Dakota · County air quality · 2025
Codington County, South Dakota
Median AQI 33 (Good). 82.1% of monitored days rated Good, direct from EPA Air Quality System stations.
- 33
- Median AQI
- 82.1%
- Good-air days
- 1
- Unhealthy days
- 58%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Codington County's air is good on balance, cleaner than the median US county, a median AQI of 33 with 82.1% of 179 monitored days in the Good band, driven mainly by PM2.5.
- 33
- median AQI · Good
- 82.1%
- days rated Good
- PM2.5
- main pollutant
- 58%
- cleaner than US counties
1 day reached Unhealthy or worse; the worst single reading hit AQI 154.
Data updated July 2026
- Good · 147 d · 82.1%
- Moderate · 30 d · 16.8%
- USG · 1 d · 0.6%
- Unhealthy · 1 d · 0.6%
How did Codington County's air break down in 2025?
Across 179 monitored days, 147 fell in the Good band (AQI 0–50) and 1 reached Unhealthy or worse. The worst single day peaked at AQI 154 (Unhealthy).
EPA AQS →Air quality data from EPA Air Quality System (2025). 179 days monitored. Median AQI: 33 (Good).
Insights: Codington County, South Dakota. EPA monitors recorded a median Air Quality Index of 33 across 179 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 147 (82%) fell in the Good band (AQI 0–50), 30 (17%) registered Moderate readings, and 1 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 57, while the worst single-day peak hit 154 (Unhealthy). Residents averaged about 24.6 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as PM2.5 (92 days), Ozone (79 days), PM10 (8 days). Across the 2020–2025 trend window, good days shifted by -146 and the median AQI moved -5 points, placing the multi-year trajectory at stable. Residents and visitors experienced 1 unhealthy-or-worse days combined, periods when the EPA recommends sensitive groups limit prolonged outdoor exertion. Nearby counties show comparable readings: Brookings (53.0% good, AQI 48); Brown (87.1% good, AQI 25); Clay (82.6% good, AQI 37); Custer (72.4% good, AQI 46); Hughes (94.4% good, AQI 14); Jackson (78.5% good, AQI 44).
Air Quality Summary
Good Days
82.1%
147 of 179 monitored days
7.1pp vs 75% target
Max AQI Recorded
154
Unhealthy
Health Grade
Good
90th-pct AQI 57
Codington County, Good days share 82.1%
National avg
Share of monitored days at AQI 0-50 (Good band).
Codington County, Unhealthy-or-worse share 0.6%
National avg
Share of monitored days above AQI 150 (Unhealthy or worse). Bar maxes at 10% (worst-county ceiling).
AQI Day Breakdown (2025)
Distribution of 179 monitored days across EPA AQI categories.
Good
147
82%
Moderate
30
17%
USG
1
1%
Unhealthy
1
1%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Codington County.
- PM2.5 · 92 days · 51.4%
- Ozone · 79 days · 44.1%
- PM10 · 8 days · 4.5%
Health Impact Assessment
Good
Codington County's air quality is rated Good based on 82.1% good air days. There were 1 unhealthy days in 2025 when outdoor activity should be limited.
Air quality is acceptable most days, but 1 days reached "Unhealthy for Sensitive Groups" (AQI 101-150) and peak AQI reached 154. Sensitive groups should monitor real-time conditions at AirNow.gov.
The dominant pollutant is PM2.5, driving AQI on 92 of 179 monitored days.
5-Year Air Quality Trend
Air quality is stable in Codington County. Best year: 2020 (293 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 293 | 72 | 1 | 0 | 38 | 101 |
| 2021 | 246 | 113 | 3 | 2 | 43 | 271 |
| 2022 | 285 | 79 | 1 | 0 | 41 | 101 |
| 2023 | 215 | 135 | 12 | 1 | 45 | 164 |
| 2024 | 269 | 91 | 1 | 0 | 37 | 102 |
| 2025 | 147 | 30 | 1 | 1 | 33 | 154 |
How does Codington County compare?
How Codington County compares
Good-day share better than US avg
Codington County 82.1%
Brookings County, South Dakota 53.0%
US average 76.5%
Median AQI better than US avg
Codington County 33
Brookings County, South Dakota 48
US average 38
Unhealthy days / yr worse than US avg
Codington County 1
Brookings County, South Dakota 1
US average 0
Other Counties in South Dakota
Air quality comparison for nearby counties in South Dakota.
Counties with Similar Air Quality
Counties across the US with a similar median AQI to Codington County.
Ascension County, Louisiana
AQI 33 · 94.1% good
Athens County, Ohio
AQI 33 · 80.3% good
Brazoria County, Texas
AQI 33 · 84.8% good
Bristol City County, Virginia
AQI 33 · 78.3% good
Carter County, Oklahoma
AQI 33 · 80.9% good
Del Norte County, California
AQI 33 · 81.0% good
What Codington County's air means for you
On most days the air here is fine, but PM2.5 drives 1 unhealthy-or-worse day a year that sensitive groups should plan around.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-PM2.5 days, the guide explains what a median of 33 means for exposure. Health guidance
- See how Codington County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Codington County with its South Dakota neighbours before drawing a conclusion about the region. All of South Dakota
Based on 179 EPA-monitored days in 2025; figures reflect only days the monitors reported. Source: EPA Air Quality System annual summaries.
More Air Quality Data
Air Quality Guides
Frequently Asked Questions
What is the air quality in Codington County, South Dakota? ▼
Codington County has a median Air Quality Index (AQI) of 33, rated "Good." 82.1% of monitored days (147 out of 179) had good air quality in 2025.
What is the main pollutant in Codington County? ▼
The primary pollutant in Codington County is Fine Particles (PM2.5), which was the main AQI driver on 92 days (51% of monitored days). Penetrates deep into lungs and bloodstream. Linked to heart disease and premature death.
How many unhealthy air days does Codington County have? ▼
In 2025, Codington County recorded 1 unhealthy air days (1 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 154.
Is the air quality in Codington County getting better or worse? ▼
Air quality in Codington County is stable based on 5-year trends (2020-2025). Best year: 2020 with 293 good days. Worst year: 2025 with 147 good days.
What does AQI 33 mean for health? ▼
Codington County's median AQI of 33 falls in the "Good" category. See the <a href="/guides/understanding-aqi" class="underline">AQI category guide</a> for what each range means for health.
How does Codington County compare to other counties in South Dakota? ▼
Codington County has 82.1% good air days. Nearby counties in South Dakota: Brookings (53.0% good), Brown (87.1% good), Clay (82.6% good), Custer (72.4% good), Hughes (94.4% good), Jackson (78.5% good).
What is the 90th percentile AQI in Codington County? ▼
The 90th percentile AQI for Codington County is 57, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 154 (Unhealthy).
Data Sources
Primary Source: U.S. Environmental Protection Agency (EPA), Air Quality System (AQS), Annual AQI by County dataset, 2020–2025 (aqs.epa.gov). For current conditions (not shown here — this page is historical annual data), see EPA AirNow (airnow.gov). See our methodology for how AQI, median, and coverage figures are computed.
Informational only, not professional advice. Data from EPA AQS. See our disclaimer.
Every figure on PlainAir is rendered directly from EPA AQS air-quality monitoring data, no number is typed in by an editor. This page draws directly on EPA AQS air-quality monitoring data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.