SmogRank / World / United States / Washington / October 2026

Most polluted cities in Washington, United States, October 2026

51 cities in Washington, United States ranked by their average PM2.5 so far (5 of 31 days). Worst: Auburn at 10.4 µg/m³, #444 of 2,246 cities in the world. Cleanest: Anacortes at 2.6. 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.

← Auburn 0% 0.75%0
Every city in Washington, United States ranked for October 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. 1Auburn
    0%
  2. 2White Center
    0%
  3. 3Columbia Citylow-cost sensors
    0%
  4. 4Tacoma
    0%
  5. 5Renton
    0%
  6. 6Kent
    0%
  7. 7Sunnyside
    0%
  8. 8Parkland
    0%
  9. 9Seattle
    0%
  10. 10Tulalip
    0%
  11. 11Shoreline
    0%
  12. 12Bremerton
    0%
  13. 13Burien
    0%
  14. 14Kirklandlow-cost sensors
    0%
  15. 14Monroelow-cost sensors
    0%
  16. 16North Creeklow-cost sensors
    0%
  17. 16Toppenish
    0%
  18. 18Chehalis
    0%
  19. 19Moses Lake
    0%
  20. 20Lacey
    0%
  21. 21Bellingham
    0%
  22. 21Grandview
    0%
  23. 21Port Angeles
    0%
  24. 24Bothelllow-cost sensors
    0%
  25. 25Airway Heights
    0%
  26. 25Picnic Point-North Lynnwood
    0%
  27. 27North Bend
    0%
  28. 27Ridgefield
    0%
  29. 29Pullman
    0%
  30. 30Bellevue
    0%
  31. 30Mount Vernon
    0%
  32. 30Walla Walla
    0%
  33. 33Finley
    0%
  34. 33Lynden
    0%
  35. 33Spokane Valley
    0%
  36. 36Longview
    0%
  37. 37Port Townsend
    0%
  38. 38Aberdeen
    0%
  39. 38Quincy
    0%
  40. 38Spokane
    0%
  41. 38Union Gap
    0%
  42. 42Union Hill-Novelty Hilllow-cost sensors
    0%
  43. 43Ellensburg
    0%
  44. 43Vancouver
    0%
  45. 45Yakima
    0%
  46. 46Mead
    0%
  47. 47Ephrata
    0%
  48. 47Wenatchee
    0%
  49. 49Tri-Cities
    0%
  50. 50Cheney
    0%
  51. 51Anacortes
    0%

Low-cost sensors: consumer units, counted only in cities with no government-grade monitor; they read close to reference monitors on the whole, but 15 to 25% high in humid air. How we use them.

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

All cities in the world, October 2026 · All cities in United States, October 2026 · Washington now

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SmogRank, most polluted cities in Washington, United States, PM2.5, October 2026 (so far), smogrank.com/us/region/washington/history/2026-10 (accessed 6 Oct 2026).

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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.