This grant provides three years of support to MOCCIE, the Modeling Consortium for Chemistry of Indoor Environments. Led by Nicola Carslaw of the University of York and Manabu Shiraiwa of UC Irvine, MOCCIE is a consortium of theoretical and experimental chemists, statisticians, computer scientists, and building experts devoted to creating high quality models of indoor chemical processes across various size and time scales. Over the next three years, MOCCIE researchers will use a variety of cutting edge techniques, including molecular dynamics simulations, kinetic process modeling, gas-phase chemistry and particle-phase modeling, thermodynamic modeling, and computational fluid dynamics in an attempt to develop  comprehensive, integrated physical-chemical models of indoor environmental chemical processes.  The models will include a detailed representation of gas-phase, particle-phase, and surface chemistry in indoor environments that simulates how occupants, indoor activities, and buildings influence indoor chemical processes. Model design will be driven by three fundamental questions. One, can we understand indoor chemical and physical processes well enough to predict them quantitatively with computer models? Two, what are the major uncertainties in these models? Three, what experiments or field measurements would improve those predictions or reduce those uncertainties? Findings will be shared through peer-reviewed publications and presentations at conferences and meetings, and the developed models will be made freely available through an easily accessible open access repository.