The Copernicus Sentinel-5P satellite carries the state-of-the-art Tropomi instrument to map a multitude of trace gases such as nitrogen dioxide, ozone, formaldehyde, sulphur dioxide, methane, carbon monoxide and aerosols – all of which affect the air we breathe and therefore our health, and our climate. With a swath width of 2600 km, it will map the entire planet every day. Information from this new mission will be used through the Copernicus Atmosphere Monitoring Service for air quality forecasts and for decision-making. Tropomi – a spectrometer – will map the global atmosphere every day with a resolution as high as 7 km × 3.5 km. At this resolution, air pollution over cities can be detected.