Bellevue vs Seattle: PM2.5 compared
Over the last year, Seattle's air was about 1.8× as polluted as Bellevue's: PM2.5 averaged 6.2 µg/m³ against 3.4, on the 349 days both cities were measured. Seattle had the dirtier air on 325 of those days, Bellevue on 22. Seattle was over the WHO's daily guideline of 15 µg/m³ on 9 of them, Bellevue on 5.
Right now
The last year, day by day
Month by month
Year by year
| Year | Bellevue | Seattle | Days Bellevue was worse |
|---|---|---|---|
| 2026 so far | 20 | 34 | 22 |
| 2025 | 19 | 34 | 16 |
| 2024 | 17 | 33 | 8 |
| 2023 | 22 | 42 | 2 |
Means in US AQI over the days both cities were measured that year; a year shows once they share 30 such days.
Each city's worst days
Bellevue
- 5 Aug 202610838.3 µg/m³
- 6 Aug 202610436.9 µg/m³
- 4 Aug 20268326.2 µg/m³
Seattle
- 6 Aug 20268527.5 µg/m³
- 5 Aug 20268226.0 µg/m³
- 4 Aug 20267522.1 µg/m³
Daily means in US AQI, with µg/m³ beside them, since the index stops at its top value, over the days both cities were measured in the last year. Each date opens that day's world board.
Compare either city with another
Bellevue
Side by side with Mecca, California (United States's worst on 30 days), Gujranwala (the world's worst on 30 days).
Seattle
Side by side with Mecca, California (United States's worst on 30 days), Gujranwala (the world's worst on 30 days).
Use this page
SmogRank, PM2.5 daily means compared, Bellevue and Seattle, 12 Oct 2025 – 11 Oct 2026, smogrank.com/compare/us-bellevue/us-seattle (accessed 12 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.
The same rules as every SmogRank figure: reference monitors first, and a day counts with 18 measured hours. How we measure.
Updated 2026-10-12 19:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index.