Collaborative Research: Formation of Organic Nitrogen and Secondary Organic Aerosol Related to Nitrate Radical Oxidation of Volatile Organic Compounds

该项目的重点是增加对人类产生的排放如何与森林的生物排放相结合以影响大气中小颗粒形成的理解。将在两种不同类型的森林(城市森林和偏远森林)部署一个流动实验室，以比较和对比氮素物种向森林的远距离和短距离运输的影响。科学活动的主要目标是：(1)描述美国中部两个森林地点的环境气溶胶、辐射和微量气体的特征；(2)使用原子比(如氧碳比，O：C)来量化在SOA中发现的氧化水平，并确定颗粒有机硝酸盐(PON)的存在对观察到的亚微米颗粒物(PM)的氧化状态的影响；(3)研究冠层内梯度和透过冠层的输送对亚微米PM、PON和氧化剂的影响；(4)确定氮氧化物(NOx)对所有地点挥发性有机碳(VOC)氧化和SOA形成的影响；(5)比较和对比偏远、道路和城市林区的化学成分；(6)利用正矩阵分解(PMF)确定在不同人为影响水平下，冠层上方和冠层以下的SOA的重要组成部分；以及(7)调查所有地点的NOx的去向。

This project focuses on increasing the understanding of how human-produced emissions combine with biogenic emissions from forests to influence the formation of small particles in the atmosphere. A mobile laboratory will be deployed to two different types of forests (urban and remote) in order to compare and contrast the impact of long-range and short-range transport of nitrogen species to forests. The results will lead to improved control strategies that minimize the health, visibility and climate effects of anthropogenic emissions.The primary objectives of the science campaign are to: (1) Characterize the ambient aerosol, radiation, and trace gases at two forest sites, both above and below the canopy, and along a north-south transect in the central United States; (2) Quantify the level of oxidation found in SOA using atomic ratios (such as the oxygen to carbon ratio, O:C) and determine the impact the presence of particulate organic nitrate (PON) has on the observed oxidation state of the submicron particulate matter (PM); (3) Investigate how in-canopy gradients and through-canopy transport impact submicron PM, PON, and oxidants; (4) Determine the impact nitrogen oxides (NOx) have on volatile organic carbon (VOC) oxidation and SOA formation in all locations; (5) Compare and contrast the chemistry of remote, on-road, and urban forested areas; (6) Identify the factors contributing to SOA using positive matrix factorization (PMF) to identify important components of SOA under different levels of anthropogenic influence both above and below canopy; and (7) Investigate the fate of NOx in all locations.