RUI: Mechanistic and Kinetic Studies of the Atmospheric Chemistry of Isoprene and its First-Generation Products

异戊二烯是一种生物来源的挥发性有机化合物，是全球碳氢化合物中排放量最大的。因此，它对对流层的组成和化学行为有重大影响。虽然异戊二烯的大气反应已经得到了广泛的研究，但反应机理复杂，许多有望成为重要反应产物的多功能化合物还没有标准可用。因此，异戊二烯化学的一些重要方面仍然知之甚少。这些包括在低氮氧化物(NOx)条件下，羟基(OH)自由基与异戊二烯反应产生的羟基过氧化氢的形成和反应，以及硝酸根与异戊二烯反应生成的异戊二烯硝酸酯的化学。这些反应可能会对氢氧自由基和NOx水平产生重大影响，并对二次有机气溶胶的形成产生重大影响。合成有机化学将与气相动力学和机理研究相结合，以阐明异戊二烯及其一些第一代产品在大气化学中的关键途径。该战略将首先合成目标反应产物(过氧化氢、硝酸甲酯和硝酸羟基酯)。然后将在静态光化学反应器和流动管中研究它们与大气氧化剂反应的动力学和机理，然后研究异戊二烯与羟基和硝酸根反应的产物表征和产率。该项目将加强本科生和研究生的教学和培训，每年为四名本科生提供机会。它将特别有效地加强代表不足的群体对科学的参与。它将继续在弗雷斯诺州立大学和国家大气研究中心(NCAR)之间建立富有成效的伙伴关系，这将促进学生作为独立科学家的发展。该项目还将支持弗雷斯诺州的外联工作，以增加进入STEM领域的学生数量和多样性，并提高社区对空气质量和气候变化问题的认识。该项目将包括科学家参加讲习班，重点是向当地地球科学教师提供必要的工具，以了解气候科学并向他们的中小学生进行交流。科学家讲座将在偏远地点举行电话会议，项目对讲习班的贡献将包括传授关于观测和模型之间的联系的知识，以及协助教师了解模型在预测气候方面的局限性和优势。

Isoprene is a biogenic volatile organic compound with the largest global emissions flux of any hydrocarbon. It thus has a major impact on the composition and chemical behavior of the troposphere. While the atmospheric reactions of isoprene have been extensively studied, the reaction mechanism is complex and standards for many of the multi-functional compounds that are expected to be important reaction products are not available. Consequently, some important aspects of isoprene chemistry are still poorly understood. These include the formation and reaction of hydroxyl hydroperoxides from the reaction of hydroxyl (OH) radicals with isoprene under low nitrogen oxide (NOx) conditions, and the chemistry of isoprene nitrates generated by the reaction between nitrate radicals and isoprene. These reactions are likely to have a substantial impact on hydrogen oxide radical and NOx levels, and on the formation of secondary organic aerosol. Synthetic organic chemistry will be combined with gas phase kinetic and mechanistic studies to elucidate key pathways in the atmospheric chemistry of isoprene and some of its first generation products. The strategy will be first to synthesize target reaction products (hydroperoxides, carbonyl nitrates and hydroxynitrates). The kinetics and mechanisms of their reactions with atmospheric oxidants will then be investigated in both static photochemical reactors and within a flow tube, followed by product characterization and yields from the reaction of isoprene with OH and nitrate radical.The project will enhance teaching and training of undergraduate and graduate students, providing opportunities to four undergraduate students each year. It will be especially effective in enhancing participation in science by underrepresented groups. It will continue a productive partnership between Fresno State and the National Center for Atmospheric Research (NCAR), which will facilitate the development of the students as independent scientists. The project will also support outreach efforts at Fresno State to both increase the number and diversity of students entering STEM fields, and to increase community awareness of air quality and climate change issues. The project will include scientist participation in workshops focused on providing local earth science teachers with tools necessary to understand and communicate climate science to their elementary and high school students. Scientist lectures will be teleconferenced to remote sites, and the project contribution to the workshops will include imparting knowledge about connections between observations and models, as well as assisting teachers in understanding the limitations and strengths of models in predicting climate.