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)计划将支持路易斯安那州立大学巴里·德林格教授的研究计划。德林格教授和他的学生将研究空气中细颗粒物中的环境持久性自由基(EPFR)对环境的影响。德林格教授的团队检测到了与新鲜采样的空气中直径小于2.5微米的颗粒物(PM2.5)相关的有机自由基，这些颗粒物在收集后可以在空气中持续几天。这些自由基的化学和毒理学特征类似于香烟烟雾中与焦油相关的自由基，并在燃烧产生的PM样本中检测到由于自由基对分解稳定，且不与空气反应，因此它们被称为环境持久性的，在水溶液中可以作为有效的还原剂。利用EPR光谱学，将添加具有可疑EPFR前体的PM2.5样品形成的EPFR与含有不同过渡金属的受控代理颗粒形成的EPFR进行比较。观测到的EPFR的衰变和寿命将作为温度、湿度和太阳辐射的函数来确定。将确定EPFR在生物条件下诱导的活性氧物种(ROS)的形成。将对EPFR参与选定大气化学的潜力进行评估。将研究与NO和臭氧的反应，以确定EPFR是否会导致这些污染物的耗尽或形成，以及硝基/氧基多环芳烃、其他含氧物种和次级自由基的形成。作为该项目的一部分，德林格博士和他的学生将向与科学有关的俱乐部和本科生课程介绍项目和研究总结。通过路易斯安那州立大学超级基金研究中心，将开展化学、燃烧和环境健康科学研究方面的研究生合作研究和跨学科培训。国际学生联合会致力于学生在国内/国际会议上的陈述，以及他们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小组和计划，包括超级基金研究计划研讨会和与生物医学研究合作者的交流计划。

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.