Continuous chemical speciation of Asian VOC emissions for understanding the growth of surface ozone in East Asia

地球表面的对流层臭氧是一种关键污染物，具有许多影响，包括健康退化，特别是肺功能和心血管系统，以及作物产量下降，特别是小麦、玉米和水稻。在世界许多地区，对流层臭氧正在减少，但在过去二十年中，东亚的对流层臭氧增长迅速。对流层中臭氧的产生是由两种前体推动的：阳光下的氮氧化物（NOx）和挥发性有机化合物（VOCs）。亚洲区域臭氧的普遍增加是由于这些前体排放，特别是来自中国的排放总体上大量增加造成的。虽然臭氧本身的趋势可以相对直接地检测到，无论是在地面还是从卫星上，跟踪背景大气中区域氮氧化物和挥发性有机化合物的长期变化在技术上更具挑战性。臭氧的产生发生在污染被解除和远距离运输的过程中，排放的影响是跨界的，往往影响到顺风国家以及最初的排放者。约克大学（University of York）最近在中国进行的VOC观测表明，中国城市和工业排放的VOCs和氮氧化物的混合物异乎寻常地向VOCs倾斜，此时对VOCs的控制将是比减少氮氧化物更有效的政策工具。这个由美国国家科学院/约克大学和国家环境研究所（NIES）合作的项目将开发和部署用于自主测量挥发性有机化合物（VOCs）的新技术，挥发性有机化合物是地面空气污染物臭氧的主要前体。开发的仪器将部署在一个独特的日本研究站（Hateruma观测站），所产生的数据将用于确定和量化挥发性有机化合物的跨界来源（地理和部门），这些来源部分造成了最近亚洲地表臭氧的显著上升趋势。对挥发性有机化合物的长期测量很少，而且很少的测量通常只覆盖非常有限的范围。在WMO GAW等长期规划中，许多关键化合物，如醇类、醛类和酮类仍未测量，较高分子量的碳氢化合物（例如来自燃料蒸发的碳氢化合物）也是如此。该项目将创造一项新技术，利用先进的电子冷却方法收集和浓缩到达研究地点的空气。重要的是，空气样本中存在的大量水将被自动和再生地去除，而不会影响被测量的挥发性有机化合物。这对于该项目将针对的关键化合物来说尤其困难。然后将使用创新的二维气相色谱系统分析干燥、浓缩的空气样品，该系统能够对复杂的挥发性有机化合物混合物进行解卷积。据我们所知，这将是有史以来第一次长期部署这种工具。通过将新技术与NIES Hateruma天文台（包括NOx）现有的世界领先的测量一起放置，为大气化学解释增加了额外的价值。该项目建立在Andrews和Saito之间的协作工作的基础上，这项后续活动创建了一个基于共享仪器开发和日本研究基础设施的全球变化观测的长期大气科学研究计划。该项目将发挥双方合作组织的现有优势，并创造一种新的技术能力，供更广泛地利用。它将产生关于大气成分的独特的新数据集，这将有助于日本管理空气污染和减轻环境风险，并支持英国和日本在控制国家间空气污染跨界传播的科学方面发挥领导作用。

Tropospheric ozone at the Earth's surface is a key pollutant, having numerous impacts including degradation in health, particularly in lung function and cardiovascular systems and reduced crop yields, particularly for wheat, maize and rice. In many regions of the world tropospheric ozone is decreasing, but East Asia has seen rapid growth in tropospheric ozone over the past two decades.Ozone production in the troposphere is fuelled by two precursors: nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of sunlight. The general increases in ozone seen regionally in Asia have been caused by large overall increases in these precursor emissions, particularly from China. Whilst the trends in ozone itself can be detected relatively straightforwardly, both at the surface and from satellites, tracking long-term changes in regional NOx and VOCs in the background atmosphere is much more technically challenging. The production of ozone occurs as pollution is lifted and transported over long distances, and the effects of emissions are trans-boundary, often impacting downwind countries as well as the original emitter.Recent VOC observations made by the University of York in China has shown that the mixture of VOCs and NOx being emitted from Chinese cities and industry is unusually skewed towards VOCs, and their control would, at this time, be a more effective policy tool than reductions in NOx.This collaborative project between the NCAS/University of York and the National Institute for Environmental Studies (NIES) will develop and deploy novel technologies for the autonomous measurement of volatile organic compounds (VOCs), key precursors to the surface air pollutant ozone. The instrumentation developed will be deployed at a unique Japanese research station (Hateruma Observatory) and the data generated used to identify and quantify the trans-boundary sources (both geographic and sectoral) of VOCs that are, in part, responsible for the significant recent upwards trends in Asian surface ozone. There are very few long-term measurements of VOCs, and what few measurements there are generally only cover a very limited range. Many critical compounds such as alcohols, aldehydes and ketones still go unmeasured in long-term programmes such as WMO GAW, as do higher molecular weight hydrocarbons, for example from fuel evaporation.The project will create a new technology, utilising advanced electronic cooling methods to collect and concentrate air arriving at the research site. Importantly, the large quantity of water present in the air sample will be removed automatically and regeneratively, without affecting the VOCs being measured. This is especially difficult for the critical compounds that this project will target.The dry, concentrated air sample will then be analysed using an innovative two dimensional gas chromatography system, able to de-convolute the complex mixture of VOCs. This would be, to our knowledge, the first ever long-term deployment of such an instrument. By co-locating the new technology alongside existing world-leading measurements made at the NIES Hateruma Observatory (including NOx), exceptional additional value is added to the atmospheric chemistry interpretation. The project builds on collaborative work between Andrews and Saito, with this follow-on activity creating a longer-term programme of atmospheric science research based around shared instrument development and global change observations from Japanese research infrastructure. The project would play to existing strengths of both partner organisations and create a new technological capability to be exploited more widely. It will generate unique new datasets on atmospheric composition that will help Japan in management of air pollution and mitigation of environmental risk, and support UK and Japanese leadership of the science that informs control of the trans-boundary spread of air pollution between countries.