SmogRank / World / United States / Washington / April 2026

Most polluted cities in Washington, United States, April 2026

48 cities in Washington, United States ranked by their average PM2.5 over the 30 days. Worst: Picnic Point-North Lynnwood at 6.9 µg/m³, #1,904 of 2,914 cities in the world. Cleanest: Bothell at 1.8. 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.

← Redmond 4% 4%0
Every city in Washington, United States ranked for April 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. 1Redmondlow-cost sensors
    4%
  2. 2Picnic Point-North Lynnwood
    0%
  3. 3Vancouver
    0%
  4. 4White Center
    0%
  5. 5Seattle
    0%
  6. 6Tacoma
    0%
  7. 7Lynden
    0%
  8. 8Bellingham
    0%
  9. 9Renton
    0%
  10. 10Toppenish
    0%
  11. 11Lacey
    0%
  12. 12Yakima
    0%
  13. 13Auburn
    0%
  14. 14Sunnyside
    0%
  15. 14Wenatchee
    0%
  16. 16Spokane
    0%
  17. 16Spokane Valley
    0%
  18. 18Ellensburg
    0%
  19. 18Liberty Lake
    0%
  20. 18Shoreline
    0%
  21. 18Tri-Cities
    0%
  22. 22Bremerton
    0%
  23. 22Burien
    0%
  24. 24Moses Lake
    0%
  25. 24Port Townsend
    0%
  26. 26Mead
    0%
  27. 27Grandview
    0%
  28. 28Chehalis
    0%
  29. 28Prosser
    0%
  30. 30Ridgefield
    0%
  31. 31Aberdeen
    0%
  32. 32Shelton
    0%
  33. 33Oak Harbor
    0%
  34. 34Kent
    0%
  35. 34Longview
    0%
  36. 34North Bend
    0%
  37. 37Airway Heights
    0%
  38. 38Columbia Citylow-cost sensors
    0%
  39. 38Walla Walla
    0%
  40. 40Kirklandlow-cost sensors
    0%
  41. 40Pullman
    0%
  42. 40Quincy
    0%
  43. 43Bellevue
    0%
  44. 43Ephrata
    0%
  45. 43Mount Vernon
    0%
  46. 46Anacortes
    0%
  47. 47Union Hill-Novelty Hilllow-cost sensors
    0%
  48. 48Bothelllow-cost sensors
    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, April 2026 · All cities in United States, April 2026 · Washington now

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SmogRank, most polluted cities in Washington, United States, PM2.5, April 2026, smogrank.com/us/region/washington/history/2026-04 (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.