Atmospheric sulfur dioxide is an important indicator of volcanic activity. Space based atmospheric sensors like GOME-2 on MetOp and OMI on EOS-Aura make it possible to detect the emissions of volcanic SO2 and monitor volcanic activity and eruptions on a global scale. With GOME-2, it is possible to detect and track volcanic eruption plumes and SO2 from passive degassing in near-real time (NRT). This is particularly important for early warning services, as increases in SO2 fluxes are an indicator for new episodes of volcanic unrest. The SO2 daily measurements from space are used for several early warning services related volcanic risk (Exupery, GlobVolcano) and for aviation warning purposes (GSE-PROMOTE).