SmogRank / Countries / Sierra Leone
Most polluted cities in Sierra Leone
1 measured city ranked by PM2.5, last 7 days. Worst: Freetown at 17.7 µg/m³, #190 in the world.
| # | City | µg/m³ | |
|---|---|---|---|
| 1 | Freetown low-cost sensorsWestern Area | 17.7 |
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
Sierra Leone 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 |
|---|---|
| Kenema estimated | ≈ 6 µg/m³ |
| Bo estimated | ≈ 7 µg/m³ |
| Koidu estimated | ≈ 5 µg/m³ |
| Makeni estimated | ≈ 7 µg/m³ |
| Waterloo estimated | ≈ 6 µg/m³ |
| Port Loko estimated | ≈ 7 µg/m³ |
| Njala estimated | ≈ 6 µg/m³ |
| Lunsar estimated | ≈ 7 µg/m³ |
| Kabala estimated | ≈ 4 µg/m³ |
| Segbwema estimated | ≈ 5 µg/m³ |
| Bumpe estimated | ≈ 6 µg/m³ |
| Mile 91 estimated | ≈ 6 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.