This grant supports a collaboration between Paul Wennberg, R. Stanton Avery Professor of Atmospheric Chemistry and Environmental Science and Engineering, California Institute of Technology, and Henrik Kjaergaard, Professor of Chemistry at the University of Copenhagen, to examine the role of autoxidation (a series of unimolecular processes that rapidly yield oxidized compounds) in indoor environments. Kjaergaard will use computational chemistry methods to diagnose the autoxidation pathways and estimate the rate coefficients for the organic peroxy radical chemistry initiated by the reactions of ozone and the hydroxyl radical with chemicals typically found indoors, especially a suite of terpenes. Complementing this approach, Wennberg will study terpene chemistry in the laboratory to evaluate the computational work and provide guidance for how to extend the calculations to more organic substrates. The pair will publish a suite of mechanistic schemes that describe the chemistry in peer-reviewed manuscripts, present their findings at conferences and meetings, and integrate their work into existing indoor chemical models.