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

该博士后研究金将支持对北极大气氯化学的研究，以及由此产生的二次有机气溶胶的可能性。北极对流层化学对研究特别重要，因为北极变暖的速度比地球上任何其他地方都快，导致海冰减少，并通过航运和石油开采将更多的人为排放引入北极空气。此外，由于北极空气的原始性质，云的形成可能受到云凝结核数量的限制，二次有机气溶胶的产生可能会改变北极的云量和辐射平衡。这项工作的结果将有助于了解气候变化对北极大气成分的影响，并将深入了解对流层卤素化学重要的其他冬季和海洋环境的化学。这项研究旨在更好地了解北极挥发性有机化合物的Cl引发氧化和含氧VOCs（OVOCs）的产生。以及它们对二次有机气溶胶（SOA）产生的贡献。本论文主要研究以下问题：（1）氯离子引发VOC低温氧化的产物和SOA产率是什么？以及（2）氯离子引发的VOCs氧化产生的OVOCs对北极地区气溶胶总产生量的贡献有多大？ 实验室和模拟实验的组合将被用来解决这些问题。将进行一系列氯原子氧化挥发性有机化合物的低温流管实验，然后在GEOS-Chem全球化学输运模型中开发更新的卤素机制，以包括实验室实验中确定的低温SOA产率。随后将进行一系列模拟实验，以量化Cl引发的VOC氧化对全球SOA形成的贡献，重点关注北极地区各种气溶胶形成途径的相对重要性。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.