SmogRank / World / United States / Washington / January 2023
Most polluted cities in Washington, United States, January 2023
44 cities in Washington, United States ranked by their average PM2.5 over the 31 days. Worst: Sunnyside at 14.1 µg/m³, #273 of 1,225 cities in the world. Cleanest: Enumclaw at 1.0. A city needs measurements on 70% of the days to be ranked.
OpenAQ's archive, where our readings come from, has almost none for 7 of these 31 days. Cities in the United States and Europe have them from the EPA's and the European Environment Agency's own records of the same monitors; elsewhere a city's average is over its other days. Why.
About 0 people in these 9 cities breathed unhealthy air on an average day of January 2023.
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.
- 1Yakima 0
- 2Toppenish 0
- 3Seattle 0
- 4Wenatchee 0
- 5Spokane 0
- 6Mead 0
- 7Spokane Valley 0
- 8Finley 0
- 9Tri-Cities 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
All cities in the world, January 2023 · All cities in United States, January 2023 · Washington now
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SmogRank, most polluted cities in Washington, United States, PM2.5, January 2023, smogrank.com/us/region/washington/history/2023-01 (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.