As for earlier major AeroCom studies, the intention here is to assemble in spring 2019 a set of model simulations representing the state of the art of aerosol modeling. Most important diagnostics for analysing aerosol life cycles and forcing are requested. Simulations for years 2010 and 1850 shall form the basis for a reference paper on phase III of AeroCom and additional experiments and analysis (eg absorption, aircraft, in-situ comparison, historical, median model…). Diagnostics are coordinated with AerChemMIP, so modelling groups may choose to link to simulations made under CMIP6. Submission of data is expected to be done to the AeroCom database at MetNo.