Chemistry Seminar: Professor Jesse Kroll, MIT

Laboratory Studies of the Atmospheric Oxidation of Reactive Organic Carbon

Organic compounds in the Earth’s atmosphere play a central role in health and climate: they can have impacts on human and ecosystem health, they influence atmospheric oxidant levels, and their oxidation products include secondary pollutants such as ozone and secondary organic aerosol. However our ability to predict these effects is limited by the wide range in chemical structures, properties, and reactivity of atmospheric organic species. In particular, organic species are subject to atmospheric oxidation, which dramatically increases the chemical complexity of the system. This talk will describe a series of laboratory experiments aimed at better constraining the evolution of organic carbon upon oxidation. In these experiments, organic compounds are oxidized in an environmental chamber, and reactants, intermediates, and products are measured using a suite of real-time mass spectrometric instruments, providing information about not only total carbon mass but also key properties that can be used to inform models (such as oxidation state and carbon number). These experiments provide insight into the completeness of the instrument suite, the changes to key chemical properties of the organic species upon multigenerational oxidation, and the agreement between measurements and predictions from detailed chemical mechanisms.