SmogRank / World / North America / United States / Oregon
Most polluted cities in Oregon, United States
43 measured cities, this year; 26 above the WHO annual guideline. Worst: Prineville at 13.1 µg/m³, #653 in the world.
About 10.5K people in these 7 cities breathed unhealthy air on an average day so far this year.
Ranked by people: each city's population times its share of unhealthy days, those with a daily mean over 35.4 µg/m³ (US AQI 101+). That is how many people living there breathed unhealthy air on an average day. Only cities measured at 2 or more places at least 3 km apart are ranked: one monitor shouldn't speak for a whole city. Population is the city itself, not its wider metro area.
The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
Estimated: cities without a monitor
Oregon 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 |
|---|---|
| Springfield | ≈ 4 µg/m³ |
| Aloha | ≈ 4 µg/m³ |
| Lake Oswego | ≈ 4 µg/m³ |
| Keizer | ≈ 3 µg/m³ |
| Tualatin | ≈ 4 µg/m³ |
| West Linn | ≈ 4 µg/m³ |
| Newberg | ≈ 4 µg/m³ |
| Wilsonville | ≈ 4 µg/m³ |
| Klamath Falls | ≈ 3 µg/m³ |
| Bethany | ≈ 4 µg/m³ |
| Hayesville | ≈ 3 µg/m³ |
| Sherwood | ≈ 4 µg/m³ |
| Happy Valley | ≈ 4 µg/m³ |
| Central Point | ≈ 3 µg/m³ |
| Troutdale | ≈ 4 µg/m³ |
| Oak Grove | ≈ 4 µg/m³ |
| Lebanon | ≈ 3 µg/m³ |
| Four Corners | ≈ 3 µg/m³ |
Bad-air episodes in Oregon
- North-western United States and Canada, 25 to 26 August 20262 days9 cities63 µg/m³peak, Hope
- North-western United States and Canada, 4 to 22 August 202619 days151 cities204 µg/m³peak, Wenatchee
- North-western United States and Canada, July and August 202616 July to 4 August 2026, 20 days118 cities168 µg/m³peak, Prineville
- Washington and Oregon, United States, January 202625 to 27 January 2026, 3 days12 cities37 µg/m³peak, Parkland
- California and Oregon, United States, January 202613 to 17 January 2026, 5 days26 cities47 µg/m³peak, Fresno
- North-western Canada and United States, September 20256 to 13 September 2025, 8 days57 cities103 µg/m³peak, Ephrata
Times when many cities around here had PM2.5 at twice their usual or more on the same days.
Use this board
SmogRank, most polluted cities in Oregon, United States, PM2.5, this year to 6 Oct 2026, 22:00 UTC, smogrank.com/us/region/oregon?w=year.
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.
Updated 2026-10-06 22:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index.