Understanding Formaldehyde and Glyoxal for New Satellite Measurements

人为排放的甲苯和乙烯等有机化合物导致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NO2排放分布图。卫星提供了排放物以及气团运动和发展的大尺度图像，例如来自排放源（例如工业区或生物源）的气团被平流输送到农村地区。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。乙二醛与甲醛的比率随不同类型的碳氢化合物而变化，例如生物排放与人为排放，以及不同类型的人为排放（例如，甲苯和乙烯预计具有不同的RGF），尽管缺乏对重要人为排放的RGF的直接测量。因此，对RGF的卫星测量可以提供关于排放性质的信息，并可用于核实排放清单，这一建议的驱动力来自最近和计划发射的卫星，这些卫星将大大改善对乙二醛、甲醛和NO2的测量。2017年，Sentinel 5P卫星发射升空，这将提供空间分辨率的一步变化（允许识别大型城市群内的污染热点）。随后将于2021年发射Sentinel 4，该卫星将进入对欧洲进行观测的地球静止轨道，并提供对RGF的高空间和时间测量。只有准确地知道乙烯和芳香化合物等重要的人为排放物产生的甲醛和乙二醛的量，这些数据才能得到充分利用，联合国森林观测和全球观测系统将开发和改进甲醛和乙二醛的光谱测量技术，并开发联合王国探测甲基乙二醛的新能力，甲基乙二醛是一种与乙二醛密切相关的化合物，可在今后的卫星活动中加以监测。将使用一个大气模拟室来研究关键的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。腔室测量测量是几个基元反应的组合的总体过程。在适当情况下，将通过对关键基本反应的补充性直接研究来支持室内测量，联合国森林观测和全球监测系统的一个重要组成部分是与我们从事卫星测量的伙伴合作，开发适当的模型来解释卫星测量结果，以便这些新仪器和测量结果的全部潜力能够用于空气质量研究，了解排放情况，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.