The Sentinel-5 Precursor mission is a single-payload satellite in a low-Earth orbit successfully launched on 13 October 2017. The mission provides daily global information at an unprecedented spatial resolution (~3.5x7km²) on trace gases and aerosols, important for air quality, climate forcing, and the ozone layer. The single payload of the mission is the TROPOspheric Monitoring Instrument (TROPOMI), which is a nadir-viewing push-broom spectrometer measuring in the ultraviolet, visible, near infrared, and shortwave infrared. The selected wavelength range allows for the observation of key atmospheric constituents, including O₃, NO₂, CO, SO₂, CH₄, CH₂O, aerosols, and clouds. The mission flies in loose formation with Suomi NPP to obtain detailed information on clouds and for further scientific exploitation of combined data products. In this combined ACP/AMT special issue the first results will be presented, including validation of operational products.