SmogRank / World / United States / Oregon / August 2026

Most polluted cities in Oregon, United States, August 2026

43 cities in Oregon, United States ranked by their average PM2.5 over the 31 days. Worst: Prineville at 49.7 µg/m³, #20 of 2,866 cities in the world. Cleanest: Brookings at 3.6. 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.

← Madras 48% 40%0
Every city in Oregon, United States ranked for August 2026, one column each, ranked by unhealthy days: height is the share of its measured days that were unhealthy, colour its average. Point at it to read a city; tap to open it.
  1. 1Madras
    48%
  2. 2Prineville
    35%
  3. 3Baker City
    19%
  4. 4Redmond
    19%
  5. 5Ontario
    17%
  6. 6La Grande
    16%
  7. 7Hood River
    16%
  8. 8Canby
    13%
  9. 9Pendleton
    13%
  10. 10Stayton
    11%
  11. 11Oregon City
    10%
  12. 12Hermiston
    10%
  13. 13The Dalles
    10%
  14. 14Eugene
    10%
  15. 15Cottage Grove
    10%
  16. 16Tigard
    10%
  17. 17Gresham
    10%
  18. 18Albany
    10%
  19. 19Silverton
    10%
  20. 20Beaverton
    10%
  21. 21Sweet Home
    10%
  22. 22Woodburn
    10%
  23. 23Dallas
    10%
  24. 24Corvallis
    7%
  25. 25Bend
    6%
  26. 26Altamont
    6%
  27. 27Salem
    6%
  28. 28Hillsboro
    6%
  29. 29Portland
    6%
  30. 30McMinnville
    6%
  31. 31Milwaukie
    6%
  32. 32North Portland
    3%
  33. 33Forest Grove
    3%
  34. 34Ashland
    0%
  35. 35Talent
    0%
  36. 36Medford
    0%
  37. 37Grants Pass
    0%
  38. 38Green
    0%
  39. 38Roseburg
    0%
  40. 40Florence
    0%
  41. 41Coos Bay
    0%
  42. 42Newport
    0%
  43. 43Brookings
    0%
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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, August 2026, smogrank.com/us/region/oregon/history/2026-08 (accessed 6 Oct 2026).

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