Worst air pollution Union, Oregon, today and tomorrow

On 20 September 2026, overall air quality in Union, Oregon is fair. AQI is the main air quality indicator at 22.6/100. Pollution peaks around 4:00 AM (O3: 22.6/100).

On 21 September 2026, air quality conditions in Union, Oregon will be better than today, with AQI forecast at good at 16.9/100. Pollution peaks around 4:00 AM (O3: 16.9/100).

Union's air quality has a clear seasonal rhythm. Typically, winter and spring bring the cleanest air, as frequent rain and consistent onshore wind clear pollution quickly, while 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.

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.

Airmine’s forecast uses CAMS (Copernicus Atmosphere Monitoring Service) as its background atmospheric model. While CAMS includes wildfire emissions, these are derived from satellite observations and are not available in real time. During rapidly evolving wildfire events, there may therefore be a delay before increased emissions are incorporated into the model. As a result, the forecast may temporarily underestimate PM₂.₅ and other pollutants associated with wildfire smoke.

During rapidly evolving wildfire events, CAMS may lag by approximately 1–2 days before increased wildfire emissions are fully represented, which can lead to temporary underestimation of PM₂.₅ concentrations in Airmine’s forecast.