Worst air pollution Bellevue & Mercer Island corridor - Seattle, today and tomorrow
Today (15 July): Air quality in Bellevue & Mercer Island corridor is fair. NO2 is fair; AQI and O3 are medium; PM2.5, PM10, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 7:00 AM (O3: 52.9/100).
Tomorrow (16 July 2026): Air quality in Bellevue & Mercer Island corridor is medium. NO2 decreases to good; all other pollutants stay as today. Pollution peaks around 4:00 AM (O3: 51.8/100). Airmine updates local air quality forecasts four times daily.
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Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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Seattle's Bellevue and Mercer Island corridor records good air quality on the eastern shore of Lake Washington, with the lake providing consistent westerly ventilation from Seattle and the suburban residential character keeping local emission sources moderate. The forested Mercer Island separation from Seattle's industrial areas reinforces cleaner conditions on most days.
Today - 15 July | Pollution peaks at 07:00
AQI:
Medium
52.9/100
PM2.5 (fine particles):
Good
12.9/100
PM10 (coarse particles):
Good
4.7/100
NO2 (nitrogen dioxide):
Fair
24.4/100
O3 (ozone):
Medium
52.9/100
SO2 (sulfur dioxide):
Good
1.1/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
7.5/100
PM1 (ultrafine particles):
Good
15.9/100
Levels show the poorest local air quality during the day
Tomorrow - 16 July | Pollution peaks at 04:00
AQI:
Medium
51.8/100
PM2.5 (fine particles):
Good
11.0/100
PM10 (coarse particles):
Good
3.8/100
NO2 (nitrogen dioxide):
Good
18.2/100
O3 (ozone):
Medium
51.8/100
SO2 (sulfur dioxide):
Good
1.0/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
11.5/100
PM1 (ultrafine particles):
Good
13.5/100
Other Landmarks in Seattle
Sports venues in Seattle
Frequently Asked Questions
Is air quality bad in Bellevue & Mercer Island corridor right now?
On 15 July 2026, overall air quality in Bellevue & Mercer Island corridor is fair. NO2 is the main pollutant at 24.4/100. Pollution peaks around 7:00 AM (O3: 52.9/100).
Will air quality be worse tomorrow in Bellevue & Mercer Island corridor?
On 16 July 2026, air quality conditions in Bellevue & Mercer Island corridor will be better than today, with AQI forecast at medium at 51.8/100. Pollution peaks around 4:00 AM (O3: 51.8/100).
When is air pollution at its worst in Bellevue & Mercer Island corridor?
Bellevue & Mercer Island corridor's air quality follows a clear seasonal pattern. Typically, rain-heavy winters keep the air unusually clean compared to much of the country, while August and September wildfire smoke can dominate the season, occasionally driving particulate levels sharply higher for several days. Prevailing onshore winds usually keep pollution moving rather than letting it settle.
Are air quality levels in Bellevue & Mercer Island corridor based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
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Data provided by Airmine — Last update: 16 July 2026 at 10:33 CEST (Data is updated four times daily.)
This forecast is produced independently using Airmine's own atmospheric data and models.
Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.
For long term forecasts and maps, see the Airmine app