The Modeling Consortium for the Chemistry of Indoor Environments (MOCCIE) is a multi-institutional collaboration devoted to developing comprehensive, integrated, physical-chemical models that simulate how occupants, indoor activities, and buildings influence indoor chemical processes. Founded with Sloan support in 2017, and overseen by Manabu Shiraiwa, Associate Professor of Chemistry at the University of California, Irvine, and Nicola Carslaw, Reader, University of York, MOCCIE links and modifies existing chemical models across a diverse range of physical scales and timeframes. The consortium also partners with experimental chemists working on the indoor environment in mutually beneficial ways. Experimental data can be used to test MOCCIE simulations, resulting in better predictions. These improved predictions, in turn, can then be used by experimentalists to generate hypotheses for further testing. Funds from this grant provide 18 months of continued support for MOCCIE. Over that time, MOCCIE will assess gaps in the fundamental understanding of indoor chemistry processes, guide experimental measurements through identification of parameters responsible for model uncertainties, indicate key species with predicted concentrations, improve design of experimental/fieldwork studies, and aid in interpretation of data from laboratory and field experiments.