Worst air pollution Viana do Castelo, today and tomorrow

On 21 July 2026, overall air quality in Viana do Castelo is medium. AQI is the main air quality indicator at 43.5/100. Pollution peaks around 3:00 PM (O3: 43.5/100).

On 22 July 2026, air quality conditions in Viana do Castelo will be similar to today, with AQI forecast at medium at 40.9/100. Pollution peaks around 5:00 PM (O3: 40.9/100).

People in Viana do Castelo tend to notice reduced air quality when oak and eucalyptus pollen peaks, or because of vehicle traffic on the A28 and neighbouring industrial and port operations; outside of those periods, conditions here remain among the more favourable in the region.

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.