This grant, to Barbara Turpin, professor and chair of the Department of Environmental Sciences and Engineering at the University of North Carolina, Chapel Hill, will fund three-year effort to examine the roles of dampness, water-soluble organic gases (WSOGs), and surface chemistry on indoor air composition. The project is designed to improve characterization of indoor WSOGs, their chemistry and fate indoors, and to provide key information needed to predict the degree to which water in damp homes may alter indoor air composition. The research will address the following questions by conducting controlled experiments with real indoor surfaces at high vs. low relative humidity: What is the uptake rate and equilibrium partitioning of WSOGs on typical indoor surfaces? How much liquid water absorbs on these surfaces and how does liquid water mediate uptake? The research will also provide insights into surface chemistry and product formation in damp homes by measuring real-time chemical changes on indoor surfaces after the introduction of key gases (ozone, water vapor, and WSOGs) using sophisticated state-of-the-art spectroscopic techniques. Finally, the UNC team will pilot real-time molecular-level characterization of WSOGs in one to three homes using high-resolution time-of-flight chemical ionization mass spectrometry (HR-ToF-CIMS) over 15 days. The project will create new knowledge about the roles of dampness, water-soluble organic gases, and surface chemistry on indoor air composition. The research findings will be shared through peer-reviewed publications and presentations at national and international conferences.