This grant funds research by University of Toronto chemist Jonathan Abbatt, who is trying to forge better kinetic and mechanistic understandings of multiphase chemistry occurring indoors. Abbatt’s work focuses on the oxidation kinetics in both the condensed-phase and volatile products and the effects of oxidation on the gas-aerosol-surface partitioning of semivolatile species. Grant funds will allow Abbatt to use state-of-the-art mass spectrometric techniques in the laboratory to address the multiphase chemistry of a range of indoor surface materials. Abbatt will document what gas-phase and condensed-phase products arise from ozonolysis of the components of skin and cooking oils, characterize the oxidation kinetics and mechanisms of indoor combustion materials, such as cigarette and cannabis smoke, determine the fate of HOCl, an important oxidant released by bleach washing, and investigate how surface oxidation affects the partitioning of surface-sorbed species. Abbatt and his team will generate important new insights into indoor chemistry. This new knowledge will be shared through peer-reviewed publications and presentations at conferences and meetings. At least two postdoctoral researchers and three students will be trained.