Air quality in Seattle today
The air in Seattle (United States) now and over the next 48 hours: the US AQI and the European AQI, fine particles (PM2.5, PM10), ozone and nitrogen dioxide, compared with the WHO 2021 guidelines, with what it means for outdoor sport, children, older people and open windows.
These numbers are more than 7 hours old, so they are hidden. Open the live map for the current air. Open the air map centred on Seattle
AQI right now
Moderate. Main pollutant: Nitrogen dioxide (NO₂), 1.7× the WHO guideline.
What to do today
- Outdoor sport Fine for almost everyone; the very sensitive may shorten long hard sessions.
- Children, older people, asthma Unusually sensitive people: watch for coughing or shortness of breath.
- Windows Open; prefer airing when the AQI is lowest (see the hours below).
AQI in Seattle hour by hour, next 48 hours
- Good
- Moderate
- Unhealthy for sensitive groups
- Unhealthy
- Very unhealthy
- Hazardous
Cleanest hour in the next 24 h: Sun 10:00 (AQI 64). Worst hour: Sat 21:00 (AQI 69).
US AQI per hour, local time. Bars coloured by category.
Compared with the WHO 2021 guidelines
| Pollutant | Next 24 h | WHO guideline | Ratio |
|---|---|---|---|
| PM2.5 | 16 µg/m³ | 15 µg/m³ | 1.1× |
| PM10 | 17 µg/m³ | 45 µg/m³ | within |
| Nitrogen dioxide (NO₂) | 41 µg/m³ | 25 µg/m³ | 1.7× |
| Ozone (O₃) | 39 µg/m³ | 100 µg/m³ | within |
PM2.5, PM10 and NO₂: 24-hour mean of the forecast against the 24-hour guideline; ozone: highest 8-hour mean against the 8-hour guideline.
Forecast for Sat 17:00 local time · updated 2026-10-25 00:41 UTC
Air quality map around Seattle
Live PM2.5 field (NOAA GEFS-Aerosols): a different model, so it can disagree with the numbers above by a few units.
More about Seattle
Bad air alert for Seattle
Air quality alerts are part of LayEarth Pro: one push the evening before the forecast US AQI in your city goes above your level, so you can move a run, a school trip or an open window in time. 7-day free trial, then 9 USD a month.
Questions
- What is the AQI in Seattle right now?
- US AQI 66 (Moderate), European AQI 39; PM2.5 12 µg/m³ (Sat 17:00).
- Is it safe to exercise outdoors in Seattle today?
- Fine for almost everyone; the very sensitive may shorten long hard sessions.
- What is the main pollutant in Seattle?
- Nitrogen dioxide (NO₂), 1.7× the WHO guideline.
- Where do the numbers come from?
- The CAMS global air-quality forecast of the Copernicus Atmosphere Monitoring Service, read through Open-Meteo: a model on a ~40 km grid, not a monitoring station. Where a nearby monitor disagrees, the monitor is right.
Nearby cities
Victoria · Vancouver · Portland · Calgary · Edmonton · Sacramento
How it is computed
Hourly CAMS forecast (Copernicus) for the coordinates of Seattle via Open-Meteo; US AQI per the US EPA breakpoints, European AQI per the EEA bands, WHO 2021 air-quality guidelines. The page is rebuilt every 3 hours. Live map.