SmogRank / World / United States / Oregon / May 2026
Most polluted cities in Oregon, United States, May 2026
42 cities in Oregon, United States ranked by their average PM2.5 over the 31 days. Worst: Tigard at 4.8 µg/m³, #2,393 of 2,852 cities in the world. Cleanest: Forest Grove at 2.5. A city needs measurements on 70% of the days to be ranked.
Ranked by unhealthy days: the share of each city's measured days with a daily mean over 35.4 µg/m³ (US AQI 101+), Unhealthy for Sensitive Groups or worse on the US EPA's scale. Ties go to the higher average.
- 1Bend 3%
- 2Tigard 0%
- 3Canby 0%
- 4Stayton 0%
- 5Ontario 0%
- 6Ashland 0%
- 6Florence 0%
- 6Gresham 0%
- 6Hood River 0%
- 10Albany 0%
- 10Coos Bay 0%
- 10Cottage Grove 0%
- 10The Dalles 0%
- 14Altamont 0%
- 14Baker City 0%
- 14Hillsboro 0%
- 14Medford 0%
- 14Salem 0%
- 19Eugene 0%
- 19Portland 0%
- 21La Grande 0%
- 21Madras 0%
- 21Oregon City 0%
- 24Hermiston 0%
- 25Beaverton 0%
- 25Silverton 0%
- 27Talent 0%
- 28Milwaukie 0%
- 28Woodburn 0%
- 30Brookings 0%
- 30Pendleton 0%
- 32Grants Pass 0%
- 32Green 0%
- 34Corvallis 0%
- 34Sweet Home 0%
- 36Redmond 0%
- 37Newport 0%
- 37Prineville 0%
- 39Dallas 0%
- 39McMinnville 0%
- 39North Portland 0%
- 42Forest Grove 0%
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
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SmogRank, most polluted cities in Oregon, United States, PM2.5, May 2026, smogrank.com/us/region/oregon/history/2026-05 (accessed 6 Oct 2026).
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.