SmogRank / Countries / United States / New Hampshire
Most polluted cities in New Hampshire, United States
4 measured cities ranked by PM2.5, last 30 days. Worst: Portsmouth at 4.1 µg/m³, #2100 in the world.
| # | City | µg/m³ | |
|---|---|---|---|
| 1 | Portsmouth New Hampshire | 4.1 | |
| 2 | Keene New Hampshire | 4.0 | |
| 3 | Derry New Hampshire | 3.9 | |
| 4 | Laconia New Hampshire | 2.6 |
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
New Hampshire 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 |
|---|---|
| Manchester estimated | ≈ 2 µg/m³ |
| Nashua estimated | ≈ 3 µg/m³ |
| Concord estimated | ≈ 2 µg/m³ |
| East Concord estimated | ≈ 2 µg/m³ |
| Derry Village estimated | ≈ 3 µg/m³ |
| Dover estimated | ≈ 3 µg/m³ |
| Rochester estimated | ≈ 3 µg/m³ |
| Salem estimated | ≈ 3 µg/m³ |
| Merrimack estimated | ≈ 2 µg/m³ |
| Bedford estimated | ≈ 2 µg/m³ |
Updated 2026-10-01 13:07 UTC. Values are PM2.5 in µg/m³ (fine particles), the median of each city's monitors.