东海大气气溶胶二元羧酸的浓度分布及其形成和来源研究.pdf

东海大气气溶胶中二元羧酸的浓度分布及其形成和来源研究 气溶胶中的二元羧酸则主要来自挥发性有机物在液相中的氧化，一次源对其贡献 较小。乙醛酸等的液相氧化生成的乙二酸和长链二元羧酸液相氧化生成的乙二酸 对东海气溶胶中乙二酸的贡献，春季分别为 41%和 59%，夏季分别为 75%和 25% 。 东海春季近海气溶胶中乙二酸和丁二酸呈双峰分布，丙二酸呈单峰分布；远 海气溶胶中乙二酸、丙二酸和丁二酸均呈双峰分布，远海气溶胶中二元羧酸在粗 粒子上的分布高于近海。远海和近海气溶胶中二元羧酸不同的粒径分布表明其有 不同的来源或形成路径。近海气溶胶中，主要分布在液滴模态上的二元羧酸来自 生物质燃烧排放的有机前体物在远距离运输过程中发生的光化学氧化生成，少量 分布在粗粒子上的二元羧酸则与海洋源有关；远海气溶胶中，液滴模态上的二元 羧酸与海洋释放有机前体物的光化学氧化过程有关，粗粒子上的二元羧酸则来自 不饱和脂肪酸在颗粒物表明发生的非均相反应生成。夏季，东海气溶胶中二元羧 酸呈现双峰分布，细粒子上的二元羧酸来自生物质燃烧以及海洋释放的有机前体 物在液相中的氧化；而海洋释放的不饱和脂肪酸在粗粒子表面发生的非均相反应 是粗粒子上二元羧酸的主要来源。 关键词：二元羧酸；气溶胶；粒径分布；东海 ii 东海大气气溶胶中二元羧酸的浓度分布及其形成和来源研究 Distributions, Sources and Formation of Dicarboxylic Acids in Atmospheric Aerosols over the East China Sea Abstract Low molecular weight dicarboxylic acids are one of identified important constituents of organic aerosols in the atmosphere. These dicarboxylic acids have low vapour pressure and easily mainly partition in the particle phase. They could affect hygroscopicity of atmospheric aerosols and reduce surface tension of aerosol droplets. The effects could increase the efficiency of aerosols to be activated as cloud condensation nuclei （CCN ） and eventually affect cloud formation, global energy balance and regional/global climate. Considered the importance, much attention has been paid to dicarboxylic acids in atmospheric aerosol particles. In this study, total suspended particles （TSP ） samples and size-fractioned particle samples were collected over the East China Sea during the periods from 12 May to 6 June and 12 to 28 August, 2011, respectively. The concentrations and size distributions of water-soluble dicarboxylic acids were measured to study their temporal and spatial distribution characteristic, di