AbstractCityChem-EPISODE, developed at Helmholtz-Zentrum Geesthacht (HZG) is designed for treating complex atmospheric chemistry in urban areas (Karl, 2017). The model is an extension of the EPISODE dispersion model to enable chemistry/transport simulations of reactive pollutants on city scale. EPISODE is an Eulerian dispersion model developed at the Norwegian Institute for Air Research (NILU) appropriate for air quality studies at the local scale (Slørdal et al. 2003 & 2008). The model is an open source code subject to the Reciprocal Public License ("RPL").