Hydrolysis is a reaction in which water is used to break down chemical bonds. Preliminary evidence suggests hydrolysis reactions could be very important indoors, breaking down common man-made ester (MME) compounds like those found in PVC pipes, and diffusing the resulting degradation products into the air. This grant funds a project by V. Faye McNeill, Associate Professor of Chemical Engineering at Columbia University, to assess the impact of hydrolysis reactions of a range of man-made esters—occurring on damp indoor surfaces—on indoor air quality. Grant funds will allow McNeill to adapt her outdoor atmospheric chemistry model, GAMMA (Gas-Aerosol Model for Mechanism Analysis), for application to the indoor environment. The adapted model, GAMMA-CIE, will introduce MME species, intermediates, and reaction products into the aqueous phase chemical mechanism, incorporate mass transfer between the aqueous and gas phases, and model oxidation in the gas phase. In addition to this modeling work, McNeill will perform laboratory measurements to provide missing data for the MME hydrolysis cascade under alkaline conditions and will examine the effect of acidic pH and ionic content of the aqueous film on MME hydrolysis kinetics. Among the MME compounds to be characterized are Texanol, a component of latex paints; TXIB (trimethyl pentanyl diisobutyrate); BBzP (benzyl butyl phthalate); and DEHA (diethylhydroxylamine). Last, McNeil will use the modified model to predict indoor air quality under typical domestic and commercial building scenarios. The model will simulate the fate of esters and the role of damp surfaces in realistic indoor conditions, providing new insights about indoor chemistry.