In the mikroMISCH project, we investigate the emissions of organic micropollutants through combined sewer overflows (CSO) into open water bodies. The aim of this project is to gain a deeper insight into the dynamics and substance spectrum of micropollutants emitted during rain events. For this, the MS2field is applied, which is a transportable high-resolution mass spectrometry platform developed at Eawag. With the MS2field, we can measure an almost unlimited number of different organic substances at a time-resolution of 20 minutes for several weeks to month with limited maintenance needs. This should facilitate (1) obtaining more realistic exposure scenarios [i.e. comparing peak-concentrations with acute quality standards], (2) identifying the different pathways of micropollutants into the sewer network [source detection by time series analysis] and (3) detecting a wider spectrum of different substances [suspect- and non-target screening].