AGS-PRF: Contribution of Oxygenated Volatile Organic Compounds (VOCs) from Chlorine Chemistry to Arctic Aerosol Production

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This Postdoctoral Research Fellowship will support investigations into atmospheric chlorine chemistry in the Arctic and the resulting potential for the creation of secondary organic aerosol. Arctic tropospheric chemistry is of particular importance for study because the Arctic is warming more rapidly than anywhere else on Earth, causing a loss of sea ice and the introduction of more anthropogenic emissions into the Arctic air through shipping and petroleum extraction. Additionally, because of the pristine nature of Arctic air in which cloud formation can be limited by the number of cloud condensation nuclei, the production of secondary organic aerosol may alter cloud cover and radiation balance in the Arctic. The results of this work will have implications for understanding the effects of the changing climate on Arctic atmospheric composition and will build insight into the chemistry of other wintertime and marine environments where tropospheric halogen chemistry is important.This research is directed toward better understanding the Cl-initiated oxidation of volatile organic compounds in the Arctic and the production of oxygenated VOCs (OVOCs) and their contribution to secondary organic aerosol (SOA) production. The following questions will be investigated: (1) What are the products and SOA yields of Cl-initiated VOC oxidation at low temperatures? And (2) How much do OVOCs from Cl-initiated oxidation of VOCs contribute to the total aerosol production in the Arctic? A combination of laboratory and modeling experiments will be used to address these questions. A series of low-temperature flow tube experiments of VOC oxidation by chlorine atoms will be conducted followed by the development of an updated halogen mechanism in the GEOS-Chem global chemical transport model to include the low-temperature SOA yields determined in the laboratory experiments. This will be followed by a series of modeling experiments to quantify the contribution of Cl-initiated VOC oxidation to SOA formation globally, with a focus on the relative importance of various aerosol formation pathways in the Arctic.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.