Sioux City, Iowa Air Quality
Sioux City air quality today — the AQI, the main pollutant, and whether it’s safe to exercise outside right now
Sioux City, IA · Air quality right now
The air quality index in Sioux City, IA is 24 (Good) right now — safe for outdoor activity.
Is it safe to be outside in Sioux City today?
AQI 24 Yes — air quality is Good
Air is clean — great for outdoor activity.Main pollutant: PM2.5Observed 1:00 AM CDT
Pollutants right now
- PM2.55.4 µg/m³Main pollutantfine particles — smoke, exhaust, soot
- PM105.6 µg/m³coarse particles — dust, pollen, ash
- Ozone46 µg/m³smog — builds on hot, sunny days
- NO₂6.4 µg/m³nitrogen dioxide — traffic, combustion
ExerciseOK to run — no air-quality limits on outdoor exercise.
How to read Sioux City’s air quality
Guides: The AQI Scale, Explained · Air Quality Alerts, Decoded · How to Read a Wildfire Smoke Map · Why Wildfire Smoke Travels 1,000 Miles.
Air quality over time in Sioux City
Across the EPA’s county records from 2020 to 2025, Sioux City’s cleanest year was 2022 (median AQI 36) and its most polluted was 2023 (median AQI 43); the typical (median) day has trended more polluted since 2020.
| Year | Median AQI | Unhealthy+ | Main pollutant | USG | Moderate | Good |
|---|---|---|---|---|---|---|
| 2020 | 39 | 0 | PM2.5 | 0 | 30 | 92 |
| 2021 | 42 | 1 | PM2.5 | 0 | 35 | 79 |
| 2022 | 36 | 0 | PM2.5 | 0 | 22 | 91 |
| 2023 | 43 | 2 | PM2.5 | 0 | 45 | 71 |
| 2024 | 43 | 0 | Ozone | 0 | 60 | 224 |
| 2025 | 39 | 0 | Ozone | 3 | 55 | 226 |
“USG” is Unhealthy for Sensitive Groups (AQI 101–150); “Unhealthy+” combines the Unhealthy, Very Unhealthy, and Hazardous days. In 2024 the EPA tightened the annual fine-particle (PM2.5) standard to 9 µg/m³ from the previous 12 µg/m³, so counties near the old limit read worse against the new one. Source: EPA AQS annual summaries, 2020–2025.
Frequently asked
- What was the worst year for air quality in Sioux City?
- In the EPA's 2020–2025 county records, 2025 had the most days above AQI 100: 3 days (3 Unhealthy for Sensitive Groups, 0 Unhealthy or worse). The highest median AQI came in 2023 (43; 2025's was 39).
- How many unhealthy air days does Sioux City have?
- Across 2020–2025, under 1% of the days reported for Sioux City's county had an AQI above 100 (6 of 1036), about 1 day a year. 2025 had 3 days.
- What's the main air pollutant in Sioux City?
- PM2.5 drove Sioux City's county AQI on the most days in 4 of 6 years (2020–2025); Ozone in 2024, 2025.