RUI: Collaborative Research on the Role of Singlet Molecular Oxygen in Urban Atmospheres Rich In Polycyclic Aromatic Hydrocarbons

在这项由环境化学科学计划资助的项目中，洛杉矶加州州立大学的克里希纳·福斯特教授和马蒂亚斯·塞尔克教授正在研究城市颗粒物对地球低层大气的影响。该项目是与加州大学欧文分校的Donald Dabdub教授合作进行的。城市颗粒物含有由不完全燃烧过程产生的多环芳烃(PAH)，包括汽油和柴油燃料的机动车辆。虽然已知一些多环芳烃会将能量转移到氧气中，形成更多的活性分子，但很难知道哪些多环芳烃负责这种能量转移，以及这种情况在环境中发生了多少次。随着该项目的实施，这些能量转移测量的范围和精度都得到了提高。这项研究的成功可能会改进空气质量模型，这些模型被用来了解污染对人们的影响，特别是那些生活在城市地区的人。协助这项研究的学生反映了南加州人口的多样性。因此，该项目有可能增加选择化学科学职业并继续研究生教育的未得到充分服务的学生的数量，满足国家对准备从事化学科学职业的学生的需求。研究人员致力于通过测量单线态氧量子产率和猝灭速率来确定多环芳烃和氧化多环芳烃是溶液中单重态分子氧的净来源。用多种分析技术对与单重态分子氧反应生成的烯烃氧化产物进行了表征。实验室实验和空气质量模型都被用来确定多环芳烃光激发在排放羽流和空气/颗粒界面上对氧化的潜在作用。

In this project funded by the Environmental Chemical Sciences Program, Professors Krishna Foster and Matthias Selke of California State University, Los Angeles are investigating the impact of urban particulate matter on the lower atmosphere of Earth. The project is performed in collaboration with Professor Donald Dabdub of the University of California at Irvine. Urban particulate matter contains polycyclic aromatic hydrocarbons (PAH) generated from incomplete combustion processes, including motor vehicles fueled by gasoline and diesel. Although some PAHs are known to transfer energy to oxygen forming more reactive molecules, it is hard to know which PAHs are responsible for this energy transfer and how many times this occurs in the environment. The scope and accuracy of these energy transfer measurements is being improved with this project. Success in this research may improve air quality models and that are used to understand the impact of pollution on people, especially those living in urban areas. The students assisting in this research reflect the diverse population of southern California. Consequently, this project has the potential to increase the number of underserved students that select careers in the chemical sciences and pursue graduate education, addressing the nation's need for students preparing for chemical sciences careers.The investigators work to identify PAH and oxygenated-PAH that are net sources of singlet molecular oxygen in solution by measuring singlet oxygen quantum yields and quenching rates. Alkene oxidation products formed from reactions with singlet molecular oxygen are characterized using multiple analytical techniques. Both laboratory experiments and air quality models are used to determine the potential role of PAH photoexcitation on oxidation in emission plumes and at the air/particle interface.