Atmospheric chemistry of reactive trace species through direct real-time measurements

“在英国，糟糕的空气质量是对公众健康最大的环境风险，据报道，它会影响身体的每个器官，与心血管和呼吸系统疾病、血管性痴呆和阿尔茨海默病等疾病有关，导致全球超过420万人过早死亡，每年给英国经济造成约150亿英镑的损失。”空气的性质和影响受大气成分的支配，了解大气成分对制定旨在改善空气质量的政策至关重要，还需要了解大气中活性微量物质的排放率、浓度和化学性质。该项目将利用时间分辨紫外和红外吸收光谱技术研究反应物质的化学和大气影响，在反应过程中实时直接测量反应物质。实验室实验将集中在克里基中间体（CIs）的化学性质上，这是一种通过臭氧（O3）与不饱和挥发性有机化合物（VOCs）的反应在大气中产生的活性物质。自1949年提出它们的存在以来，一个特别的挑战是直接测量ci。2012年报道的CIs光解源的出现促进了CIs的实验室研究，并使人们对CIs的化学和性质有了更深入的了解，但在大气相关条件下Criegee中间反应的动力学和机制仍然存在很大的不确定性。最近在nerc资助下，该小组使用光解CI源开发新技术来监测大气相关条件下Criegee中间反应的动力学和产物。该项目将研究CI +水反应的动力学，这在大气中很重要，但尚未详细探索。紫外和红外吸收技术的结合将使这些反应的动力学、机制和产物产量的研究成为可能，并为ci -水配合物在大气中的潜在作用提供见解。也将有机会发展紫外线吸收实验，对OH反应性进行现场测量，这是对氧化为二次污染物的空气团中活性污染物总负荷的测量，并在大气模拟室中对CIs进行测量，以直接和定量地探索臭氧分解反应中的Criegee中间体。该项目与NERC有关大气污染与人类健康、清洁空气和气候的目标有关。”

"Poor air quality represents the greatest environmental risk to public health in the UK, and has been reported to affect every organ in the body, with links to illnesses including cardiovascular and respiratory diseases, vascular dementia, and Alzheimer's disease causing over 4.2 million premature deaths worldwide and costing the UK economy ~£15 billion each year. The properties and impacts of our air are governed by atmospheric composition, the understanding of which is vital to the development of policies aimed at improving air quality and requires knowledge of the emission rates, concentrations and chemistry of reactive trace species in the atmosphere. This project will investigate the chemistry and atmospheric impacts of reactive species using time-resolved ultraviolet and infrared absorption spectroscopy to make direct measurements of reactive atmospheric species in real-time during the course of their reactions. Laboratory experiments will focus on the chemistry of Criegee intermediates (CIs), a family of reactive species generated in the atmosphere through the reactions of ozone (O3) with unsaturated volatile organic compounds (VOCs). A particular challenge since the proposal of their existence in 1949 has been the direct measurement of CIs. The advent of photolytic sources for CIs, reported in 2012, has facilitated laboratory studies of CIs and has enabled greater understanding of the chemistry and properties of CIs, but there are still significant uncertainties regarding the kinetics and mechanisms of Criegee intermediate reactions under atmospherically relevant conditions.Recent NERC-funded work in this group has used photolytic CI sources to develop novel techniques to monitor the kinetics and products of Criegee intermediate reactions under atmospherically relevant conditions. This project will investigate the kinetics of CI + water reactions, which are atmospherically important but have yet to be explored in detail. The combination of UV and IR absorption techniques will enable the investigation of the kinetics, mechanisms, and product yields of these reactions, and provide insight to the potential role of CI-water complexes in the atmosphere.There will also be opportunities to develop the UV absorption experiment to make field measurements of OH reactivity, a measure of the total loading of reactive pollutants in an air mass that oxidise to secondary pollutants, and to make measurements of CIs in an atmospheric simulation chamber to explore Criegee intermediates directly, and quantitatively, in ozonolysis reactions. This project links to the NERC objectives related to atmospheric pollution and human health, clean air, and climate. "