Caltech Young Investigators Lecture

Abstract

Chemical transformations in the atmosphere control the distribution of pollutants that impact air quality, human health, and the climate. A key class of such chemical transformations is the oxidation of volatile organic compounds (VOCs) which impacts both ozone production and the formation of secondary organic aerosol (SOA). Each generation of VOC oxidation is initiated by an oxidant to form an organic peroxy radical (RO₂) which can then react with several bimolecular reaction partners or undergo unimolecular isomerization. As such, atmospherically relevant laboratory studies must match both the distribution of oxidants and RO₂ fates in the global atmosphere. Here we present a new approach for laboratory studies of atmospheric SOA production, using isoprene as a model system. Our approach uses global modeling with GEOS-Chem to understand the distribution of oxidants and RO₂ fates in the atmosphere followed by box modeling of laboratory conditions to assess how experiments can be designed to match atmospheric conditions. With this approach, we are able to run our laboratory experiments under more realistic atmospheric conditions than are typically accessed.

Bio

Dr. Hannah S. Kenagy (she/her) is an atmospheric chemist working as an NSF Postdoctoral Fellow at MIT. Kenagy did her undergraduate work at the Univ. of Chicago before completing a PhD in Chemistry as an NSF Graduate Research Fellow at UC Berkeley. Her research uses an integrated combination of measurement and modeling techniques to study atmospheric chemical pathways that contribute to the production and fate of air pollutants globally. Kenagy's PhD work used a combination of airborne field measurements and modeling to better understand the urban chemistry of nitrogen oxides, pollutants which impact the production of ozone and aerosol particles. As a postdoc, Kenagy is integrating modeling and laboratory studies to disentangle the effects of multi-generation oxidation on the formation of atmospheric organic aerosols. Kenagy also enjoys mentoring students and fostering in them an excitement for atmospheric chemistry, as well as doing outreach to make science accessible to all.

This lecture is part of the Young Investigators Lecture Series sponsored by the Caltech Division of Engineering & Applied Science.