Sioux Falls Air Quality in August
Across 2019–2025, Sioux Falls's August air quality had a median AQI of 40 (Good) over 217 monitored days in the Sioux Falls, SD area. 1.8% of August days (4 of 217) reached Unhealthy for Sensitive Groups or worse, and ground-level ozone set the daily AQI on 59.0% of days. The cleanest August on record here was 2019 (median AQI 36, 0 days above 100) and the worst was 2021 (median 42, 2 days above 100, peak AQI 108).
- Good: 76.5%
- Moderate: 21.7%
- Unhealthy for Sensitive Groups: 1.8%
- Unhealthy or worse: 0.0%
Reduce Indoor Ozone in Sioux Falls
Today's main pollutant in Sioux Falls is ground-level ozone (AQI 24). Important: standard HEPA filters do NOT remove ozone — only a purifier with a substantial activated-carbon bed adsorbs it. The biggest wins are cutting indoor sources (gas appliances, certain "ionizer" purifiers) and ventilating when outdoor ozone is low (early morning). A high-carbon unit helps with the gases and VOCs that linger indoors.
Recommended: Levoit Core 300 — True HEPA + activated carbon · CADR ~141 CFM · rooms up to 219 sq ft
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How is the air in Sioux Falls in August?
Good on a typical day: median AQI 40 across 2019–2025, with 1.8% of August days above AQI 100. Ground-level ozone is the main driver.
- ✓76.5% of August days were Good (AQI 0–50), 21.7% Moderate (51–100).
- ✓4 days of 217 reached AQI 101+; the August peak was 125.
- ✓Best August: 2019; worst August: 2021.
Frequently asked questions
What is the air quality like in Sioux Falls in August?▾
Across 2019–2025, the median daily AQI in Sioux Falls in August was 40 (Good). 76.5% of days were Good, 21.7% Moderate, and 1.8% reached Unhealthy for Sensitive Groups or worse, based on 217 monitored days in EPA's Air Quality System.
Is August a good time for outdoor exercise in Sioux Falls?▾
A typical August day in Sioux Falls sits in the Good range (median AQI 40), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 56 of August days (1.8%) reached AQI 101+ in 2019–2025.
Which pollutant causes Sioux Falls's August air quality problems?▾
Ground-level ozone set the daily AQI on 59.0% of August days in Sioux Falls. The highest August AQI recorded in 2019–2025 was 125 (Unhealthy for Sensitive Groups), in 2021.
Sioux Falls August air quality, year by year
Sioux Falls August air quality by year (Sioux Falls, SD, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 31 | 36 | 0 | 50 | O3 |
| 2020 | 31 | 41 | 0 | 58 | O3 |
| 2021worst | 31 | 42 | 2 | 108 | PM2.5 |
| 2022 | 31 | 42 | 0 | 97 | O3 |
| 2023 | 31 | 49 | 0 | 90 | PM2.5 |
| 2024 | 31 | 39 | 0 | 69 | O3 |
| 2025 | 31 | 41 | 2 | 125 | PM2.5 |
What August air means in Sioux Falls
A typical August day in Sioux Falls sits in the Good range (median AQI 40), so running, cycling and children's outdoor play are fine for everyone on most days; about 1 day in 56 of August days (1.8%) reached AQI 101+ in 2019–2025.
August's median AQI of 40 is in line with Sioux Falls's whole-year median of 38, so this period is neither a clean nor a dirty stretch for the area. Nationally, the median August AQI across every EPA metro area (104,152 metro-days, 2019–2025) is 45, so Sioux Falls runs below the national August norm; 1.8% of its August days topped AQI 100 versus 3.5% nationally (below average).
August is part of Sioux Falls's summer season (June, July, August); the summer page pools all three months.
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Sioux Falls
The latest EPA AirNow observation puts Sioux Falls's AQI at 24 (O3). The figures above are multi-year month statistics, not today's reading.
View current Sioux Falls air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Sioux Falls, SD), 2019–2025. Daily AQI per CBSA is the highest AQI reported by any monitor in the area that day; the defining parameter is the pollutant that set it. Month and season statistics pool every such day in the period across all years listed. Retrieved 2026-09-09.