Collaborative Research: Laboratory Studies of the Role of Organic Peroxy Radicals (RO2) Chemistry on the Evolution of Atmospheric Organic Carbon

Massachusetts Institute Of Technology, Cambridge MA

Investigators

Abstract

The goal of this project is to improve knowledge about reactive chemistry and the atmospheric oxidation of organic compounds. A suite of instruments will be used in the laboratory to develop a more complete understanding of how certain chemical regimes control the amount, identity, and properties of gas-phase and aerosol products during atmospheric oxidation. This project will yield new insights into the chemistry underlying the formation of atmospheric organic aerosol, an important component influencing air quality and global climate. This project is focused on peroxy radical (RO2) chemistry and how it controls the distribution of reaction products formed during the atmospheric oxidation of organic compounds. Volatile organic compounds will be oxidized in an environmental chamber under carefully-controlled RO2 reaction conditions, and the formation and evolution of the resulting products will be measured using a suite of real-time time-of-flight mass spectrometric techniques to provide information on the concentration, chemical formula, oxidation state, and volatility of organic species. Key outputs include comprehensive measurements of gas- and particle-phase products, volatility distributions (including secondary organic aerosol yields), and evolving OH reactivities. Finally, measurements of key ensemble properties of the reaction mixture (e.g., carbon oxidation state, carbon number) will be compared against predictions from state-of-the-art atmospheric chemical mechanisms. Results from this project can be used in 3D models, and time-dependent concentrations will be made publicly available as a community resource for testing and refining state-of-the-art models of atmospheric oxidation and the formation of secondary organic aerosol. This project includes training for early-career scientists, including both graduate and undergraduate students. 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.