SmogRank / Countries / United States / Colorado
Most polluted cities in Colorado, United States
13 measured cities ranked by PM2.5, this year. Worst: Greeley at 6.8 µg/m³, #1809 in the world.
| # | City | µg/m³ | |
|---|---|---|---|
| 1 | Greeley Colorado | 6.8 | |
| 2 | Thornton Colorado | 6.7 | |
| 3 | Longmont Colorado | 6.3 | |
| 4 | Fort Collins Colorado | 6.2 | |
| 5 | Arvada low-cost sensorsColorado | 5.9 | |
| 6 | Denver Colorado | 5.8 | |
| 7 | Colorado Springs Colorado | 5.4 | |
| 8 | Windsor Colorado | 5.4 | |
| 9 | Pueblo Colorado | 5.3 | |
| 10 | Cañon City Colorado | 4.9 | |
| 11 | Boulder Colorado | 4.9 | |
| 12 | Ken Caryl Colorado | 4.8 | |
| 13 | Parker low-cost sensorsColorado | 2.0 |
Good 0–9.0Moderate 9.1+Unhealthy for sensitive groups 35.5+Unhealthy 55.5+Very unhealthy 125.5+Hazardous 225.5+No data
Estimated: cities without a monitor
Colorado cities we can't measure, with model estimates for the last 7 days. Listed by population, not ranked: estimates aren't precise enough to rank. Model estimates from the Copernicus Atmosphere Monitoring Service (CAMS), adjusted to measured cities nearby where there are any. Adjusted, a single day lands within ×1.5 of what a monitor would read about two times in three; unadjusted, it can be off by half or double. Treat them as a guide, not a measurement.
| City | 7-day estimate |
|---|---|
| Aurora estimated | ≈ 5 µg/m³ |
| Centennial estimated | ≈ 5 µg/m³ |
| Highlands Ranch estimated | ≈ 5 µg/m³ |
| Loveland estimated | ≈ 3 µg/m³ |
| Broomfield estimated | ≈ 3 µg/m³ |
| Grand Junction estimated | ≈ 3 µg/m³ |
| Castle Rock estimated | ≈ 3 µg/m³ |
| Commerce City estimated | ≈ 5 µg/m³ |
| Dakota Ridge estimated | ≈ 4 µg/m³ |
| Englewood estimated | ≈ 5 µg/m³ |
| Security-Widefield estimated | ≈ 3 µg/m³ |
| Wheat Ridge estimated | ≈ 4 µg/m³ |
| Pueblo West estimated | ≈ 3 µg/m³ |
| Fountain estimated | ≈ 3 µg/m³ |
| Lafayette estimated | ≈ 3 µg/m³ |
| Columbine estimated | ≈ 4 µg/m³ |
| Erie estimated | ≈ 3 µg/m³ |
| Evans estimated | ≈ 4 µg/m³ |
| Louisville estimated | ≈ 3 µg/m³ |
| Clifton estimated | ≈ 3 µg/m³ |
| Montrose estimated | ≈ 1 µg/m³ |
| Sherrelwood estimated | ≈ 3 µg/m³ |
| Durango estimated | ≈ 3 µg/m³ |
| Greenwood Village estimated | ≈ 5 µg/m³ |
Updated 2026-10-01 14:07 UTC. Values are PM2.5 in µg/m³ (fine particles), the median of each city's monitors.