This grant funds a three-year collaboration between Jonathan Abbatt, professor of chemistry, and Jeffrey Siegel, associate professor of civil and mineral engineering, to expand our understanding of multiphase chemistry in indoor environments. The overall goal of their grant-supported work is to better understand the nature of the reactive processes that affect the composition of material deposited on indoor surfaces and to examine the associated impacts on the state of the indoor environment. Abbatt and Siegel have chosen three common sources of materials that deposit on surfaces indoors: skin oil materials from people; particles generated by combustion processes such as cooking or cigarette smoking; and common chlorine- and nitrogen-containing cleaning agents such as household bleach. They will expose these chemicals to indoor air under both laboratory and real-world conditions and observe how such exposure leads to particulate deposits and the creation of new compounds. Abbatt and his team will use a comprehensive range of state-of-the-art mass spectrometer instrumentation to conduct the chemical analyses. Most of these instruments have been rarely, if ever, used indoors and the team expects to develop new analytical methods for their deployment indoors. The team will share their findings through peer-reviewed publications and presentations at conferences and meetings. At least one postdoctoral fellow and three students will be trained during the project.