SmogRank / Countries / United States / Maine
Most polluted cities in Maine, United States
4 measured cities ranked by PM2.5, last 30 days. Worst: Portland at 4.5 µg/m³, #1965 in the world.
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
Maine 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 |
|---|---|
| West Scarborough estimated | ≈ 3 µg/m³ |
| South Portland estimated | ≈ 3 µg/m³ |
| South Portland Gardens estimated | ≈ 3 µg/m³ |
| Auburn estimated | ≈ 3 µg/m³ |
| Biddeford estimated | ≈ 3 µg/m³ |
| Sanford estimated | ≈ 2 µg/m³ |
| Saco estimated | ≈ 3 µg/m³ |
| Westbrook estimated | ≈ 3 µg/m³ |
| Waterville estimated | ≈ 2 µg/m³ |
| Brunswick estimated | ≈ 2 µg/m³ |
Updated 2026-10-01 16:07 UTC. Values are PM2.5 in µg/m³ (fine particles), the median of each city's monitors.