Worst air pollution Winchester, today and tomorrow

On 9 August 2026, overall air quality in Winchester is fair. PM1 is the main pollutant at 23.5/100. Pollution peaks around 3:00 PM (O3: 56.2/100).

On 10 August 2026, air quality conditions in Winchester will be similar to today, with AQI forecast at fair at 33.3/100. Pollution peaks around 5:00 PM (O3: 33.3/100).

Here's the thing about Winchester: air quality has a clear seasonal rhythm. Come summer, it's ozone rather than particulates that's the bigger concern, especially on still, sunny days. In deep winter, a lack of wind lets A55 traffic fumes and woodsmoke settle instead of blowing through. Spring and autumn don't usually cause much concern, sitting comfortably between winter's peak and summer's ozone spikes.

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.