Kinetic and Mechanistic Studies of Criegee Intermediate Reactivity

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The Environmental Chemical Sciences program of the Chemistry Division funds Professor Craig Murray of the University of California, Irvine to explore the chemical reactivity of Criegee intermediates. Criegee intermediates are reactive chemical species that play an important role in the atmosphere. They contribute to particle formation, which can affect air quality, health and climate. Laboratory experiments measure the intermediate concentrations over time to determine the speed of their reaction with atmospheric trace gases. The research project provides training for graduate and undergraduate students on technical laboratory and other transferable skills that will prepare them for careers in academia or industry. Professor Murray's outreach program establishes air quality and weather monitoring stations at several local high schools. Outdoor and indoor particle sensors provide long-term data at each location. Student and teacher participants develop projects that use mobile particle sensors interfaced with smartphones. This outreach component broadens participation and encourages students to continue to participate in STEM activities, both inside and outside the classroom. A laser flash photolysis transient absorption spectroscopy apparatus is used to quantify the temperature-dependent kinetics of Criegee intermediate reactions with trace atmospheric gases. The experiments examine the kinetics of reactions of Criegee intermediates with multifunctional volatile organic compounds to analyze photolytically co-generated radical species and explore the role of water vapor as a potential catalyst. Complementary quantum chemical and kinetics calculations provide further insight into the detailed reaction mechanisms. The research generates data to test and refine chemical models of the atmosphere and explores how reactions of gas-phase species lead to the formation of secondary organic aerosol particles that may affect air quality, health, and climate.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.