The Role of Environmentally Persistent Free Radicals in the Chemistry of Airborne PM2.5

化学系的环境化学科学（ECS）项目将支持路易斯安那州立大学Barry Dellinger教授的研究项目。Dellinger教授和他的学生将研究空气微粒中环境持久性自由基（EPFRs）对环境的影响。德林杰教授的研究小组已经检测到与新鲜采样的空气中直径小于2.5微米（PM2.5）的颗粒有关的有机自由基，这些颗粒在收集后可以在空气中存留数天。这些自由基的化学和毒理学特征与香烟烟雾中的焦油相关的自由基相似，并在燃烧产生的PM样品中检测到。由于自由基既易于分解又不易与空气反应，因此它们被称为环境持久性，在水溶液中可作为有效的还原剂。利用EPR光谱学，将含有疑似EPFR前体的PM2.5剂量样品形成的EPFR与含有不同过渡金属的受控替代颗粒形成的EPFR进行比较。观测到的epfr的衰变和寿命将根据温度、湿度和太阳辐照度的函数来确定。epfr诱导的生物条件下活性氧（ROS）的形成将被确定。将评价epfr参与选定大气化学的潜力。将研究与NO和O3的反应，以确定EPFRs是否导致这些污染物的消耗或形成，以及硝基/氧基多环芳烃，其他含氧物质和次生自由基的形成。作为该项目的一部分，Dellinger博士和他的学生将向科学附属俱乐部和本科课程展示项目和研究摘要。在化学、燃烧和环境健康科学研究方面，研究生的合作研究和跨学科培训将通过路易斯安那州立大学超级基金研究中心进行。PI致力于学生在国家/国际会议上发表演讲，并参与路易斯安那州立大学已经建立的几个高影响力的教育和外展团体和项目，包括超级基金研究项目研讨会和与生物医学研究合作者的交流项目。

The Environmental Chemical Sciences (ECS) program of the Division of Chemistry will support the research program of Prof. Barry Dellinger of Louisiana State University. Prof. Dellinger and his students will study the environmental impact of Environmentally Persistent Free Radicals (EPFRs) in airborne fine particles. Prof. Dellinger's group has detected organic free radicals associated with freshly sampled airborne particles that are less than 2.5 micrometers in diameter (PM2.5), which can persist in air for several days after collection. The chemical and toxicological characteristics of these radicals are similar to radicals associated with the tar in cigarette smoke, and detected in samples of combustion-generated PM. Since the radicals are both stable toward decomposition and resistant to reaction with air, they are referred to as environmentally persistent and may serve as effective reducing agents in aqueous solution. Using EPR spectroscopy, EPFRs formed from dosing samples of PM2.5 with suspected EPFR precursors, will be compared to EPFRs formed on controlled surrogate particles containing different transition metals. The decay and lifetimes of the observed EPFRs will be determined as a function of temperature, humidity, and solar irradiation. EPFR-induced formation of reactive oxygen species (ROS) under biological conditions will be determined. The potential for EPFRs to participate in selected atmospheric chemistry will be evaluated. Reactions with NO and O3 will be studied to determine if EPFRs result in depletion or formation of these pollutants as well as formation of nitro-/oxy-PAH, other oxygenated species, and secondary radicals.As part of this project, Dr. Dellinger and his students will present project and research summaries to science-affiliated clubs and undergraduate programs. Collaborative research and interdisciplinary training of graduate students in chemistry, combustion, and environmental health sciences research will be conducted through the LSU Superfund Research Center. The PI is committed to student presentations at national/international meetings and their participation in several high impact education and outreach groups and programs already established at LSU, including the Superfund Research Program seminars and exchange program with biomedical research collaborators.