The new European Copernicus satellite Sentinel-4 has sent its first images from space, marking an important milestone for air quality monitoring in Europe.

A fixed observatory for air quality

Launched in July 2025, Sentinel-4 is part of the first European space mission to provide hourly observations related to air quality. Unlike polar-orbit satellites, which fly over the entire planet at low altitude, it operates from a geostationary orbit at approximately 36,000 kilometres above Earth and constantly observes the same area: Europe and North Africa.

The first images released by the European Space Agency (ESA) show the distribution of the main pollutant gases above the European continent: nitrogen dioxide, sulphur dioxide and ozone.

Once fully operational (it is currently in an initial "commissioning" phase), the satellite will provide essential data for atmospheric research, climate modelling and European environmental policy. Sentinel-4 is indeed part of the broader Copernicus programme, developed by the European Commission and ESA to supply open-source data on the terrestrial environment. Its observations will be able to support the air quality forecasting services of the Copernicus Atmosphere Monitoring Service (CAMS), contributing to public health prevention and urban planning.

With Sentinel-4, Europe will have access to a continuous, high-resolution atmospheric observation system. A step forward towards a more precise understanding of the air we breathe, and of the impact our activities have on the climate.