Worst air pollution Arboretum & Washington Park - Seattle, today and tomorrow

Today (15 July): Air quality in Arboretum & Washington Park is medium. AQI and O3 are medium; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 7:00 AM (O3: 52.9/100).
Tomorrow (16 July 2026): Air quality in Arboretum & Washington Park is medium. All 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 Arboretum and Washington Park record good air quality on the eastern side of Capitol Hill, with the extensive Japanese garden and arboretum tree canopy providing strong natural filtration. The park's sheltered valley position beside Lake Washington channels clean easterly lake breezes, keeping readings well below the western Seattle industrial corridor.

Today - 15 July | Pollution peaks at 07:00

AQI:

Medium

52.9/100

PM2.5 (fine particles):

Good

12.2/100

PM10 (coarse particles):

Good

4.4/100

NO2 (nitrogen dioxide):

Good

19.1/100

O3 (ozone):

Medium

52.9/100

SO2 (sulfur dioxide):

Good

0.8/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Good

7.5/100

PM1 (ultrafine particles):

Good

15.0/100

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

10.4/100

PM10 (coarse particles):

Good

3.6/100

NO2 (nitrogen dioxide):

Good

13.3/100

O3 (ozone):

Medium

51.8/100

SO2 (sulfur dioxide):

Good

0.7/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Good

11.5/100

PM1 (ultrafine particles):

Good

12.7/100

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Frequently Asked Questions

Is air quality bad in Arboretum & Washington Park right now?

On 15 July 2026, overall air quality in Arboretum & Washington Park is medium. AQI is the main air quality indicator at 52.9/100. Pollution peaks around 7:00 AM (O3: 52.9/100).

Will air quality be worse tomorrow in Arboretum & Washington Park?

On 16 July 2026, air quality conditions in Arboretum & Washington Park will be similar to 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 Arboretum & Washington Park?

At Arboretum & Washington Park, air quality tends to follow Seattle's broader seasonal rhythm, as spring is often the freshest stretch, sandwiched between winter rain and summer fire season; by contrast, August and September wildfire smoke can dominate the season, occasionally driving particulate levels sharply higher for several days. Winter temperature inversions can briefly trap wood-smoke in low-lying valleys, but these episodes are usually short-lived.

Are air quality levels in Arboretum & Washington Park 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