Greeley, Colorado Air Quality
Greeley air quality today — the AQI, the main pollutant, and whether it’s safe to exercise outside right now
Greeley, CO · Air quality right now
The air quality index in Greeley, CO is 32 (Good) right now — safe for outdoor activity.
Is it safe to be outside in Greeley today?
AQI 32 Yes — air quality is Good
Air is clean — great for outdoor activity.Main pollutant: OzoneObserved 1:00 AM MDT
Pollutants right now
- PM2.58.7 µg/m³fine particles — smoke, exhaust, soot
- PM109.2 µg/m³coarse particles — dust, pollen, ash
- Ozone34 µg/m³Main pollutantsmog — builds on hot, sunny days
- NO₂20 µg/m³nitrogen dioxide — traffic, combustion
ExerciseOK to run — no air-quality limits on outdoor exercise.
How to read Greeley’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 Greeley
Across the EPA’s county records from 2020 to 2025, Greeley’s cleanest year was 2022 (median AQI 51) and its most polluted was 2023 (median AQI 55); the typical (median) day has held roughly steady since 2020.
| Year | Median AQI | Unhealthy+ | Main pollutant | USG | Moderate | Good |
|---|---|---|---|---|---|---|
| 2020 | 52 | 0 | Ozone | 13 | 187 | 166 |
| 2021 | 54 | 1 | Ozone | 39 | 169 | 156 |
| 2022 | 51 | 0 | Ozone | 10 | 185 | 170 |
| 2023 | 55 | 1 | Ozone | 4 | 214 | 146 |
| 2024 | 54 | 2 | Ozone | 19 | 196 | 149 |
| 2025 | 52 | 0 | Ozone | 6 | 196 | 163 |
“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 Greeley?
- In the EPA's 2020–2025 county records, 2021 had the most days above AQI 100: 40 days (39 Unhealthy for Sensitive Groups, 1 Unhealthy or worse). The highest median AQI came in 2023 (55; 2021's was 54).
- How many unhealthy air days does Greeley have?
- Across 2020–2025, 4% of the days reported for Greeley's county had an AQI above 100 (95 of 2192), about 16 days a year. 2025 had 6 days.
- What's the main air pollutant in Greeley?
- Ozone: it drove Greeley's county AQI on the most days in every year of the EPA's 2020–2025 records.