Median AQI
36
Good
South Dakota · County air quality · 2025
Minnehaha County, South Dakota
Median AQI 36 (Good). 82.4% of monitored days rated Good, direct from EPA Air Quality System stations.
- 36
- Median AQI
- 82.4%
- Good-air days
- 0
- Unhealthy days
- 58%
- Cleaner than US counties
The verdict
According to EPA Air Quality System monitoring data, Minnehaha County's air is good on balance, cleaner than the median US county, a median AQI of 36 with 82.4% of 182 monitored days in the Good band, driven mainly by Ozone.
- 36
- median AQI · Good
- 82.4%
- days rated Good
- Ozone
- main pollutant
- 58%
- cleaner than US counties
Not one day crossed into the Unhealthy tier; the worst single reading was AQI 115.
Data updated July 2026
- Good · 150 d · 82.4%
- Moderate · 31 d · 17.0%
- USG · 1 d · 0.5%
How did Minnehaha County's air break down in 2025?
Across 182 monitored days, 150 fell in the Good band (AQI 0–50) and 0 reached Unhealthy or worse. The worst single day peaked at AQI 115 (USG).
EPA AQS →Air quality data from EPA Air Quality System (2025). 182 days monitored. Median AQI: 36 (Good).
Insights: Minnehaha County, South Dakota. EPA monitors recorded a median Air Quality Index of 36 across 182 measured days in 2025, earning a Good classification and a Good health grade. Of those days, 150 (82%) fell in the Good band (AQI 0–50), 31 (17%) registered Moderate readings, and 1 (1%) reached Unhealthy for Sensitive Groups. The 90th-percentile AQI settled at 58, while the worst single-day peak hit 115 (USG). Residents averaged about 24.7 clean-air days per 30-day window during the monitoring year.
The full pollutant mix ranks as Ozone (147 days), PM2.5 (32 days), PM10 (2 days), CO (1 days). Across the 2020–2025 trend window, good days shifted by -148 and the median AQI moved -2 points, placing the multi-year trajectory at stable. The worst single reading over the 2020–2025 window was AQI 115, usg but never Unhealthy. Nearby counties show comparable readings: Brookings (53.0% good, AQI 48); Brown (87.1% good, AQI 25); Clay (82.6% good, AQI 37); Codington (82.1% good, AQI 33); Custer (72.4% good, AQI 46); Hughes (94.4% good, AQI 14).
Air Quality Summary
Good Days
82.4%
150 of 182 monitored days
7.4pp vs 75% target
Max AQI Recorded
115
USG
Health Grade
Good
90th-pct AQI 58
Minnehaha County, Good days share 82.4%
National avg
Share of monitored days at AQI 0-50 (Good band).
Minnehaha County, Unhealthy-or-worse share 0.0%
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 182 monitored days across EPA AQI categories.
Good
150
82%
Moderate
31
17%
USG
1
1%
Unhealthy
0
0%
Very Unhealthy
0
0%
Hazardous
0
0%
Pollutant Breakdown
Days where each pollutant was the primary driver of AQI readings in Minnehaha County.
- Ozone · 147 days · 80.8%
- PM2.5 · 32 days · 17.6%
- PM10 · 2 days · 1.1%
- CO · 1 days · 0.5%
Health Impact Assessment
Good
Minnehaha County's air quality is rated Good based on 82.4% good air days. No unhealthy air days were recorded in 2025.
Air quality was acceptable on 82.4% of monitored days in 2025, with a median AQI of 36. Unusually sensitive people can check real-time conditions at AirNow.gov during high-pollution events.
The dominant pollutant is Ozone, driving AQI on 147 of 182 monitored days.
5-Year Air Quality Trend
Air quality is stable in Minnehaha County. Best year: 2022 (300 good days).
| Year | Good | Moderate | USG | Unhealthy | Median AQI | Max AQI |
|---|---|---|---|---|---|---|
| 2020 | 298 | 68 | 0 | 0 | 38 | 90 |
| 2021 | 266 | 78 | 3 | 2 | 39 | 193 |
| 2022 | 300 | 64 | 1 | 0 | 39 | 105 |
| 2023 | 235 | 103 | 23 | 4 | 44 | 181 |
| 2024 | 297 | 66 | 2 | 0 | 34 | 145 |
| 2025 | 150 | 31 | 1 | 0 | 36 | 115 |
How does Minnehaha County compare?
How Minnehaha County compares
Good-day share better than US avg
Minnehaha County 82.4%
Brookings County, South Dakota 53.0%
US average 76.5%
Median AQI better than US avg
Minnehaha County 36
Brookings County, South Dakota 48
US average 38
Unhealthy days / yr about average
Minnehaha County 0
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 Minnehaha County.
Aroostook County, Maine
AQI 36 · 84.1% good
Berkeley County, South Carolina
AQI 36 · 92.2% good
Carter County, Kentucky
AQI 36 · 89.8% good
Claiborne County, Tennessee
AQI 36 · 96.3% good
Clark County, Illinois
AQI 36 · 92.1% good
Cobb County, Georgia
AQI 36 · 92.5% good
What Minnehaha County's air means for you
The air here stays in the breathable range year-round, with Ozone the main thing to watch.
- Sensitive groups (asthma, heart conditions, children, older adults) should check the AQI on high-Ozone days, the guide explains what a median of 36 means for exposure. Health guidance
- See how Minnehaha County ranks against every monitored U.S. county on Good-day share. County rankings
- Compare Minnehaha County with its South Dakota neighbours before drawing a conclusion about the region. All of South Dakota
Based on 182 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 Minnehaha County, South Dakota? ▼
Minnehaha County has a median Air Quality Index (AQI) of 36, rated "Good." 82.4% of monitored days (150 out of 182) had good air quality in 2025.
What is the main pollutant in Minnehaha County? ▼
The primary pollutant in Minnehaha County is Ozone (O3), which was the main AQI driver on 147 days (81% of monitored days). Can trigger asthma, reduce lung function, and cause chest pain.
How many unhealthy air days does Minnehaha County have? ▼
In 2025, Minnehaha County recorded 0 unhealthy air days (0 Unhealthy, 0 Very Unhealthy, 0 Hazardous). The maximum AQI reached 115.
Is the air quality in Minnehaha County getting better or worse? ▼
Air quality in Minnehaha County is stable based on 5-year trends (2020-2025). Best year: 2022 with 300 good days. Worst year: 2025 with 150 good days.
What does AQI 36 mean for health? ▼
Minnehaha County's median AQI of 36 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 Minnehaha County compare to other counties in South Dakota? ▼
Minnehaha County has 82.4% good air days. Nearby counties in South Dakota: Brookings (53.0% good), Brown (87.1% good), Clay (82.6% good), Codington (82.1% good), Custer (72.4% good), Hughes (94.4% good).
What is the 90th percentile AQI in Minnehaha County? ▼
The 90th percentile AQI for Minnehaha County is 58, meaning 90% of monitored days had an AQI at or below this level. The maximum AQI recorded was 115 (USG).
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.