Understanding Formaldehyde and Glyoxal for New Satellite Measurements

人为排放的有机化合物，如甲苯和乙烯，造成了空气质量差和气候变化。目前，人们对空气质量问题非常感兴趣，重点关注空气污染对健康和经济的重大影响。为了制定、监测和评估控制措施，我们必须能够监测人为排放的数量、组成和空间分布。卫星测量已经提供了与空气质量问题有关的重要数据，例如与空气质量有关的二氧化氮排放分布的图片。卫星提供排放和气团运动和发展的大比例图，例如来自排放源（例如工业区或生物源）的气团正平流到农村地区。然而，卫星无法看到上面讨论的主要有机排放物，但它们可以看到它们的两种氧化产物：乙二醛和甲醛。乙二醛与甲醛（RGF）的比率随不同类型的碳氢化合物（如生物源排放与人为排放）以及不同类型的人为排放（如甲苯和乙烯预计具有不同的RGF）而变化，尽管缺乏对重要人为排放的RGF的直接测量。因此，卫星测量大气环流可提供有关排放性质的资料，并可用于核查排放清单。这一提议的推动力来自最近和计划发射的卫星，这些卫星将大大改善乙二醛、甲醛和二氧化氮的测量。2017年，哨兵5P卫星发射，将提供空间分辨率的阶跃变化（允许识别大城市内的污染热点）。随后，哨兵4号将于2021年发射到地球静止轨道，观测欧洲，并提供RGF的高空间和时间测量。只有准确地知道重要的人为排放物如乙烯和芳香族化合物的甲醛和乙二醛的产率，才能充分利用这些数据。联合国监测组将开发甲醛和乙二醛的光谱测量技术并确定其特征，并开发英国检测甲基乙二醛的新能力，甲基乙二醛是乙二醛的一种密切相关的化合物，可在未来的卫星运动中进行监测。大气模拟室将用于研究主要人为乙二醛和甲基乙二醛形成化合物如甲苯、苯、乙烯和乙醇醛的氧化。实验室测量的是几个基本反应的综合过程。在适当的情况下，将通过对关键元素反应的补充直接研究来支持室测量。联合国气候监测组的一个重要组成部分是与致力于卫星测量的合作伙伴合作，开发适当的模型来解释卫星测量，以便利用这些新仪器和测量的全部潜力，促进空气质量研究、了解排放以及与健康的联系。

Man-made emissions of organic compounds such as toluene and ethene contribute to poor air quality and climate change. Currently there is a lot of interest in air quality issues focusing on the significant health and economic impacts of air pollution. In order to formulate, monitor and evaluate control measures it is vital that we are able to monitor the amount, composition and spatial distribution of anthropogenic emissions.Satellite measurements have already provided important data relevant for air quality issues, for example pictures of the distribution of NO2 emissions relevant for air quality. Satellites provide large scale pictures of emissions and the movement and development of airmasses, for example an airmass from an emissions source (e.g. an industrial area, or biogenic sources) being advected over rural areas. However, satellites cannot see the primary organic emissions discussed above, but they can see two of their oxidation products: glyoxal and formaldehyde. The ratio of glyoxal to formaldehyde (RGF) varies with different types of hydrocarbons e.g. biogenic vs anthropogenic emissions and also different types of anthropogenic emissions (e.g. toluene and ethene are predicted to have different RGF) although there is a lack of direct measurements of RGF for important anthropogenic emissions. Satellite measurements of RGF can therefore provide information on the nature of the emissions and can be used to verify emission inventories.The driver for this proposal comes from recent and planned launches of satellites that will significantly improve measurements of glyoxal, formaldehyde and NO2. In 2017 the Sentinel 5P satellite was launched which will provide a step change in spatial resolution (allowing identifications of pollution hot-spots within large conurbations). This will be followed in 2021 by Sentinel 4 which will be launched into a geostationary orbit observing Europe and providing both high spatial and temporal measurements of RGF. These data can only be fully utilized if the yield of formaldehyde and glyoxal from important anthropogenic emissions such as ethene and aromatic compounds is known accurately.UNFOGS will develop and characterise spectroscopic measurement techniques of formaldehyde and glyoxal and develop a new UK capability for detection of methylglyoxal, a closely related compound to glyoxal which may be monitored in future satellite campaigns. An atmospheric simulation chamber will be used to study the oxidation of key anthropogenic glyoxal and methylglyoxal forming compounds such as toluene, benzene, ethene and glycolaldehyde. The chamber measurements measure overall processes which are a combination of several elementary reactions. The chamber measurements will be supported, where appropriate, by complementary direct studies of key elementary reactions.An important component of UNFOGS is to work with our partners, who are working on satellite measurements, to develop appropriate models to interpret satellite measurements so that the full potential of these new instruments and measurements can be utilized to benefit air quality studies, an understanding of emissions, and links to health.