Des Moines Air Quality in Fall
Across 2019–2025, Des Moines's fall (September–November) air quality had a median AQI of 39 (Good) over 637 monitored days in the Des Moines-West Des Moines, IA area. 0.2% of fall days (1 of 637) reached Unhealthy for Sensitive Groups or worse, and fine particulate matter (PM2.5) set the daily AQI on 71.6% of days. The cleanest fall on record here was 2019 (median AQI 32, 0 days above 100) and the worst was 2023 (median 47, 1 day above 100, peak AQI 105).
- Good: 72.7%
- Moderate: 27.2%
- Unhealthy for Sensitive Groups: 0.2%
- Unhealthy or worse: 0.0%
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How is the air in Des Moines in fall?
Good on a typical day: median AQI 39 across 2019–2025, with 0.2% of fall days above AQI 100. Fine particulate matter (PM2.5) is the main driver.
- ✓72.7% of fall days were Good (AQI 0–50), 27.2% Moderate (51–100).
- ✓1 day of 637 reached AQI 101+; the fall peak was 105.
- ✓Cleanest month: November; worst month: September.
Frequently asked questions
What is the air quality like in Des Moines in fall?▾
Across 2019–2025, the median daily AQI in Des Moines in fall was 39 (Good). 72.7% of days were Good, 27.2% Moderate, and 0.2% reached Unhealthy for Sensitive Groups or worse, based on 637 monitored days in EPA's Air Quality System.
Is fall a good time for outdoor exercise in Des Moines?▾
A typical fall day in Des Moines sits in the Good range (median AQI 39), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of fall days reached AQI 101+ in 2019–2025.
Which pollutant causes Des Moines's fall air quality problems?▾
Fine particulate matter (PM2.5) set the daily AQI on 71.6% of fall days in Des Moines. The highest fall AQI recorded in 2019–2025 was 105 (Unhealthy for Sensitive Groups), in 2023.
Des Moines fall air quality, year by year
Des Moines fall air quality by year (Des Moines-West Des Moines, IA, EPA AQS daily AQI)
| Year | Days monitored | Median AQI | Days above 100 | Peak AQI | Main pollutant |
|---|---|---|---|---|---|
| 2019cleanest | 91 | 32 | 0 | 63 | PM2.5 |
| 2020 | 91 | 36 | 0 | 61 | PM2.5 |
| 2021 | 91 | 39 | 0 | 77 | PM2.5 |
| 2022 | 91 | 37 | 0 | 66 | PM2.5 |
| 2023worst | 91 | 47 | 1 | 105 | PM2.5 |
| 2024 | 91 | 43 | 0 | 93 | PM2.5 |
| 2025 | 91 | 42 | 0 | 76 | PM2.5 |
What fall air means in Des Moines
A typical fall day in Des Moines sits in the Good range (median AQI 39), so running, cycling and children's outdoor play are fine for everyone on most days; fewer than 1% of fall days reached AQI 101+ in 2019–2025.
Fall's median AQI of 39 is below Des Moines's whole-year median of 44, making it one of the area's cleaner periods. Nationally, the median Fall AQI across every EPA metro area (296,275 metro-days, 2019–2025) is 40, so Des Moines runs in line with the national Fall norm; 0.2% of its Fall days topped AQI 100 versus 1.5% nationally (below average).
Within the season, November is the cleanest month (median AQI 37, 0.0% of days above 100) and September the worst (median 43, 0.5% above 100).
Activity-specific thresholds: running, cycling, kids' sports.
Right now in Des Moines
The latest EPA AirNow observation puts Des Moines's AQI at 32 (PM2.5). The figures above are multi-year season statistics, not today's reading.
View current Des Moines air quality →Source: EPA Air Quality System (AQS) pre-generated Daily AQI by CBSA files — daily AQI by CBSA (Des Moines-West Des Moines, IA), 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.