Direct Studies of Peroxy Radical Autoxidation Reactions

由植物排放的生物挥发性有机化合物（BVOCs）通过设定大气中气溶胶的背景水平而在气候中起着至关重要的作用。气溶胶与太阳辐射相互作用，对气候产生冷却作用。BVOCs也会影响氮氧化物循环并产生臭氧。对流层中的臭氧是大气层的最低层，是一种强大的温室气体，会使气候变暖，也是对空气质量产生负面影响的主要污染物。过氧自由基是参与这些物理化学过程的关键中间体，并且以无数的结构差异形成。据预测，这些结构具有不同的化学反应性，因此产生气溶胶和臭氧的潜力也各不相同。然而，直到最近在近红外光腔衰荡光谱学的突破，了解过氧自由基的结构和反应性的分布，从而对气溶胶和臭氧的影响，是不可能的。在这里，我们提出了一个结合实验室和地球系统建模项目，将测量的关键结构依赖的过氧自由基的物理化学性质，从最重要的BVOCs（异戊二烯和α-蒎烯），并整合这些知识，模拟BVOCs对气候的影响比以往任何时候都更忠实。该项目的成果将直接有益于大气和物理科学的学术研究人员以及规划近期和长期环境和气候变化的决策者。该项目将帮助Rabi Chhantyal Pun博士在诺丁汉大学开始一项新的研究计划，重点是实验室光化学，并得到剑桥大学亚历山大阿奇博尔德教授的建模支持。它还将为一名新的博士后研究助理提供最先进的实验室和大气化学培训。

Biogenic volatile organic compounds (BVOCs), emitted by plants, play a crucial role in climate by setting the background levels of aerosol in the atmosphere. Aerosols interact with solar radiation and have a cooling affect on climate. BVOCs also affect the NOx cycle and produce ozone. Ozone in the troposphere, lowest level of the atmosphere, is a potent greenhouse gas which warms the climate and also a major pollutant which negatively impacts air quality. Peroxy radicals are key intermediates involved in these physio-chemical processes and are formed with myriad of structural differences. These structures are predicted to have different chemical reactivities and thus varied potential to produce aerosols and ozone. However, until the recent breakthroughs in near infrared cavity ring-down spectroscopy understanding the distribution of peroxy radical structures and reactivity, and so the effects on aerosols and ozone, was impossible. Here we propose a combined laboratory and Earth system modelling project which will measure the key structure dependent physio-chemical properties of peroxy radicals from the most important BVOCs (isoprene and alpha-pinene), and integrate this knowledge to simulate the impacts of BVOCs on climate more faithfully than ever possible before. The results from this project will be of direct benefit to academic researchers in atmospheric and physical sciences and policy makers planning for the environmental and climate changes in the near and long-term future. This project will help Dr Rabi Chhantyal Pun to start a new research program focused on laboratory photochemistry at the University of Nottingham, with modelling support from Prof Alexander Archibald at the University of Cambridge. It will also provide state of the art laboratory and atmospheric chemistry training for a new postdoctoral research associate.