Reaction Dynamics of Reactive Organic Carbon

相当多的科学研究旨在为全球变化带来的令人不安的影响提供答案。越来越需要采用新的方法来探索通常非常复杂和相互关联的大气化学。在过去的30年里，光谱学为燃烧和大气科学中的许多基本问题提供了答案，但由于复杂混合物中相关物质的光谱特征难以反卷积，这些研究最好是在受控环境中的单一反应条件下进行的。此外，传统反应器通常无法观察到热分解过程中的低浓度中间体。因此，需要新的方法，如质谱法，在更相关的反应条件下利用增加的检测选择性。质谱法在同分异构体产品的情况下是不够的，因为它们具有相同的m/z比。因此，我们也采用更具选择性的成像阈值光电子能谱（TPES）。除了纯气相过程外，必须阐明气溶胶表面和水/冰滴的作用，以便形成燃烧和大气化学的完整图景。因此，本建议包括使用反应串联质谱法对目标分子与质子化水团簇的相互作用进行实验探索。长期目标是在分子水平上为活性有机碳的大气化学提供更具体的机制基础。在短期内，我们将重点关注甲酸盐（用作燃料添加剂和杀虫剂）、过氧乙酰基硝酸盐（pan，二氧化氮的长距离转运体）和萜烯（由植物释放）。我们将探索它们通过热解的热分解、氧化的反应性以及它们与水团簇的相互作用，以获得它们在大气中的更完整的行为图。加拿大政府估计，每年有14,600人过早死亡与空气污染有关。加拿大有哮喘症状的天数约为270万，空气污染估计每年给加拿大经济造成1140亿美元的损失。鉴于当前政府雄心勃勃的2050年净零排放目标，能够预测活性有机碳的空气质量结果对于能够瞄准对更清洁的未来至关重要的物种至关重要。

Considerable scientific research is oriented to providing answers to the disturbing effects of the impacts of global change. There is a growing need to introduce new methodologies to explore the often very complex and interconnected chemistry of the atmosphere. Over the past 30 years spectroscopy has provided many of the answers to fundamental questions in combustion and atmospheric science, but these studies are best undertaken under single reaction conditions in controlled environments due to the difficulty of deconvolving the spectroscopic signatures of related species in complex mixtures. In addition, conventional reactors are typically incapable of observing low concentration intermediates in the thermolysis process. Thus, new approaches such as mass spectrometry are required that take advantage of increasing detection selectivity under more relevant reaction conditions. Mass spectrometry alone, though, is insufficient in the case of isomeric products as they have the same m/z ratio. Thus, we also employ the more selective imaging threshold photoelectron spectroscopy (TPES). In addition to purely gas-phase processes, the role of aerosol surfaces and water/ice droplets must be elucidated in order to create a complete picture of combustion and atmospheric chemistry. Thus, this proposal includes the experimental exploration of the interaction of the target molecules with protonated water clusters using reactive tandem mass spectrometry.  The long term goals are to provide a more concrete mechanistic basis for the atmospheric chemistry of reactive organic carbon at the molecular level.  In the short term, we are focusing on formates (used as fuel additives and pesticides), peroxyactylnitrates (PANs, long distance transporters for NO2) and terpenes (released by vegetation).  We will explore their thermal decomposition by pyrolysis, their reactivity by oxidation and their interactions with water clusters to obtain a more complete map of their atmospheric behaviour.  The Government of Canada estimates that 14,600 premature deaths per year can be linked to air pollution. The number of asthma symptom days in Canada is around 2.7 million with air pollution estimated to cost the Canadian economy $114 billion per year. With the current government's ambitious net-zero emission goals for 2050, being able to predict the air quality outcomes of reactive organic carbon is crucial to be able to target species that are key to a cleaner future.