Des Moines Best & Worst AQI Days: Air Quality Guide
The worst air quality day on record for Des Moines (Des Moines-West Des Moines, IA area) was July 4, 2020, when the daily AQI reached 199 (Unhealthy), set by fine particulate matter (PM2.5), in wildfire smoke season. Across 2,557 monitored days in 2019–2025, 5 of the 10 worst days were Unhealthy (AQI 151+) or worse; 8 of the 10 were driven by fine particulate matter (PM2.5) and 2 by ground-level ozone, and 7 of them fell in 2023. The cleanest day was November 5, 2024 at AQI 7 (Good); the 10 best days span 6 different years.
Improve Indoor Air Quality
Even with good outdoor air in Des Moines, indoor PM2.5, dust and allergens build up. A True-HEPA purifier keeps a bedroom or office consistently clean.
Recommended: Levoit Core 400S — True HEPA · CADR ~141 CFM · rooms up to 219 sq ft
As an Amazon Associate, we earn from qualifying purchases.
When were Des Moines's worst and best air quality days?
Worst: July 4, 2020, AQI 199 (Unhealthy, PM2.5). Best: November 5, 2024, AQI 7 (Good). Based on 2,557 EPA-monitored days in the Des Moines-West Des Moines, IA area, 2019–2025.
- ✓5 of the 10 worst days were Unhealthy (AQI 151+) or worse; the 10th-worst was AQI 127 (Unhealthy for Sensitive Groups).
- ✓Fine particulate matter (PM2.5) drove 8 of the 10 worst days.
- ✓2023 accounts for 7 of the 10 worst days.
Frequently asked questions
What was the worst air quality day in Des Moines?▾
July 4, 2020: the Des Moines-West Des Moines, IA area's daily AQI hit 199 (Unhealthy), driven by fine particulate matter (PM2.5), in wildfire smoke season. That is the highest of 2,557 monitored days in 2019–2025.
What was the best air quality day in Des Moines?▾
November 5, 2024, with a daily AQI of 7 (Good). The daily AQI is the highest reading from any monitor in the area, so even the cleanest day reflects the area's worst monitor.
What was Des Moines's worst air quality day in 2025?▾
July 31, 2025, AQI 136 (Unhealthy for Sensitive Groups), set by fine particulate matter (PM2.5), in wildfire smoke season.
Which pollutant causes Des Moines's worst air days?▾
Fine particulate matter (PM2.5) set the AQI on 8 of the 10 worst days; ground-level ozone on 2. The tables above list the defining pollutant for every day.
Des Moines's 10 worst air quality days, 2019–2025
Highest daily AQI recorded for the Des Moines-West Des Moines, IA area (EPA AQS). The daily AQI is the highest reading from any monitor in the area that day.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2020 page) | 199 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 2 | (2023 page) | 166 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 3 | (2023 page) | 159 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 4 | (2020 page) | 155 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 5 | (2023 page) | 154 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 6 | (2025 page) | 136 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 7 | (2023 page) | 130 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
| 8 | (2023 page) | 129 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
| 9 | (2023 page) | 129 | Unhealthy for Sensitive Groups | O3 — ground-level ozone, in peak ozone season |
| 10 | (2023 page) | 127 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
Worst day of each year in Des Moines
The single highest-AQI day in each year on record. Click a year for its full month-by-month statistics.
| Year | Worst day | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 2019 | 100 | Moderate | O3 — ground-level ozone, in peak ozone season | |
| 2020 | 199 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2021 | 110 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2022 | 89 | Moderate | PM2.5 — fine particulate matter (PM2.5) | |
| 2023 | 166 | Unhealthy | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season | |
| 2024 | 93 | Moderate | O3 — ground-level ozone | |
| 2025 | 136 | Unhealthy for Sensitive Groups | PM2.5 — fine particulate matter (PM2.5), in wildfire smoke season |
Des Moines's 10 best air quality days, 2019–2025
Lowest daily AQI recorded for the Des Moines-West Des Moines, IA area. Ties are listed most recent first.
| # | Date | AQI | Category | Defining pollutant |
|---|---|---|---|---|
| 1 | (2024 page) | 7 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 2 | (2021 page) | 7 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 3 | (2022 page) | 8 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 4 | (2025 page) | 9 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 5 | (2024 page) | 9 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 6 | (2020 page) | 9 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 7 | (2019 page) | 9 | Good | O3 — ground-level ozone |
| 8 | (2020 page) | 10 | Good | O3 — ground-level ozone |
| 9 | (2025 page) | 11 | Good | PM2.5 — fine particulate matter (PM2.5) |
| 10 | (2024 page) | 11 | Good | PM2.5 — fine particulate matter (PM2.5) |
Right now in Des Moines
The latest EPA AirNow observation puts Des Moines's AQI at 32 (PM2.5). The days above are historical records, 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.