Anthropogenic Influence on Oxidative Capacity and BVOC Oxidation During GoAmazon 2014

该项目的重点是提高对亚马逊地区大气氧化能力控制过程的机制理解，该地区具有高浓度的生物源性挥发性有机化合物（BVOC），并调查这些过程的人为影响。这些目标将通过在巴西工业城市玛瑙斯（人口200万）的亚马逊中部下风的实地研究来实现，研究将在两个密集的工作期间（2014年2月/ 3月和8月/ 10月）进行。亚马逊河流域是开展这项工作的良好地点，因为强烈的阳光、以异戊二烯为主的高BVOC排放和持续的高OH浓度导致了快速的光化学处理和二次有机气溶胶（SOA）的形成。BVOC氧化产物，如乙二醛、甲基全球醛和甲醛，具有不同的oh依赖性形成或损失途径，将用于氧化产物比例和建模工作，以确定湿季和干季BVOC氧化的关键化学机制。在雨季，预计在该场址进行的测量将提供与“清洁”条件有关的数据，而在旱季，预计来自玛瑙斯的污染羽流将影响该场址，提供有关人为影响（特别是氮氧化物）对BVOC氧化的信息。更好地了解这些机制将澄清在热带森林中与BVOC反应后羟基自由基回收的程度。这项研究将有助于改进全球/区域对温室气体寿命和前体排放对气候、空气质量、公共健康和环境的气溶胶效应的预测。这是对美国能源部和巴西政府支持的更大的GoAmazon-2014运动的重要贡献，该运动旨在研究耦合的大气-云-陆地热带系统。

This project is focused on improving the mechanistic understanding of processes controlling the oxidative capacity of the atmosphere in the Amazon, a region with high concentrations of biogenic volatile organic compounds (BVOC), and investigating the anthropogenic influences on these processes. These objectives will be pursued through a field study in the central Amazon downwind of the industrial city of Manaus (population 2 million), Brazil, during two intensive operating periods (IOPs) (Feb/Mar and Aug/Oct 2014). The Amazon is a good location for this work since the intense sunlight, high BVOC emissions dominated by isoprene, and sustained high OH concentrations result in rapid photochemical processing and formation of secondary organic aerosol (SOA).In-situ measurements of BVOC oxidation products, such as glyoxal, methylgloxal, and formaldehyde, that have different OH-dependent formation or loss pathways, will be used along oxidation product ratios and modeling efforts to determine the key chemical mechanisms of BVOC oxidation during both the wet and dry seasons. During the wet season, measurements at the site are expected to provide data related to "clean" conditions, while during the dry season the polluted plume from Manaus is expected to impact the site, providing information about the anthropogenic influence (especially that of NOx) on BVOC oxidation. A better understanding of these mechanisms will clarify the extent to which hydroxyl radicals are recycled following reactions with BVOC in tropical forests. This research will to contribute to improved global/regional prediction of greenhouse-gas lifetimes and aerosol effects from precursor emissions on climate, air quality, public health, and the environment. It is an important contribution to the larger GoAmazon-2014 campaign supported by the U.S. Department of Energy and the government of Brazil to look at the coupled atmosphere-cloud-terrestrial tropical systems.