SmogRank / World / United States / Washington / August 2026
Most polluted cities in Washington, United States, August 2026
56 cities in Washington, United States ranked by their average PM2.5 over the 31 days. Worst: Wenatchee at 44.6 µg/m³, #33 of 2,866 cities in the world. Cleanest: Port Townsend at 4.1. A city needs measurements on 70% of the days to be ranked.
About 171K people in these 14 cities breathed unhealthy air on an average day of August 2026.
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.
- 1Spokane 59.2K
- 2Spokane Valley 24.5K
- 3Tri-Cities 23.6K
- 4Yakima 18.1K
- 5Wenatchee 14.1K
- 6Kirklandlow-cost sensors 9.7K
- 7Redmondlow-cost sensors 8.98K
- 8Bothelllow-cost sensors 2.86K
- 9North Creeklow-cost sensors 2.73K
- 10Union Hill-Novelty Hilllow-cost sensors 2.69K
- 11Mead 2.35K
- 12Toppenish 1.45K
- 13Finley 622
- 14Seattle 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.
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, August 2026 · All cities in United States, August 2026 · Washington now
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SmogRank, most polluted cities in Washington, United States, PM2.5, August 2026, smogrank.com/us/region/washington/history/2026-08 (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.