SmogRank / World / United States / Washington / March 2023
Most polluted cities in Washington, United States, March 2023
11 cities in Washington, United States ranked by their average PM2.5 over the 31 days. Worst: Kent at 7.3 µg/m³, #565 of 867 cities in the world. Cleanest: Spokane Valley at 3.4. A city needs measurements on 70% of the days to be ranked.
OpenAQ's archive, where our readings come from, has almost none for 20 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; many cities elsewhere are missing from this board, not clean. Why.
Washington has 56 cities ranked over the last 30 days, but only 11 here: most of its monitors have no readings for March 2023 in OpenAQ's archive, where ours come from, or too few to rank. Cities missing from this board weren't clean, just not measured.
About 0 people in these 3 cities breathed unhealthy air on an average day of March 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.
- 1Seattle 0
- 2Yakima 0
- 3Spokane Valley 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, March 2023 · All cities in United States, March 2023 · Washington now
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SmogRank, most polluted cities in Washington, United States, PM2.5, March 2023, smogrank.com/us/region/washington/history/2023-03 (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.