Seasonal variation of secondary organic aerosol tracers in Central Tibetan Plateau
Seasonal variation of secondary organic aerosol tracers in Central Tibetan Plateau
复制标题
青藏高原中部次生有机气溶胶示踪剂的季节变化
DOI：
10.5194/acp-15-8781-2015
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发表时间：
2015-08
影响因子：
6.3
通讯作者：
Wang X.-M.
中科院分区：
文献类型：
--
作者：
Shen R.-Q.;Ding X.;He Q.-F.;Cong Z.-Y.;Yu Q.-Q.;Wang X.-M.
抽象。二次有机气溶胶（SOA）影响着地球辐射平衡和全球气候。高海拔地区是全球气候变化的敏感地区。然而，目前，SOA的起源和季节变化在偏远的高海拔地区研究不足。在这项研究中，从2012年7月至2013年7月在青藏高原中部偏远的纳木错（NC）站点收集颗粒物样品，并分析了来自生物（异戊二烯，单萜和β-carbellene）和人为（芳烃）前体的SOA示踪剂。在这些化合物中，异戊二烯SOA（SOAI）示踪剂占大多数（26.6 ± 44.2 ng m−3），其次是单萜SOA（SOAM）示踪剂（0.97 ± 0.57 ng m−3），芳香族SOA（SOAA）示踪剂（2，3-二羟基-4-氧代戊酸，DHOPA，0.25 ± 0.18 ng m−3）和β-香芹烯SOA示踪剂（β-香芹烯酸，0.09 ± 0.10 ng m−3）。SOAI示踪剂在夏季表现出高浓度，在冬季低水平。SOAI示踪物和异戊二烯排放的温度依赖性相似，表明NC站点SOAI示踪物的季节变化主要受异戊二烯排放的影响。SOAI（2-甲基甘油酸与2-甲基四醇）的高NOx与低NOx产物的比例在冬季最高，夏季最低，这主要是受温度和相对湿度的影响。SOAM示踪剂的季节变化受单萜排放和气粒分配的影响。在夏秋季节，温度对SOAM示踪剂的分配效应是影响SOAM示踪剂变化的主导过程;而在冬春季季节，温度对SOAM示踪剂的排放效应是影响SOAM示踪剂变化的主导过程。SOAM示踪剂水平没有升高，在夏季温度升高，可能是由于温度对排放和分配的影响的抵消。DHOPA的浓度比世界城市地区报告的浓度低1-2个数量级。由于邻近的孟加拉国和印度东北部的空气污染物的输送，Dhopa在夏季呈现相对较高的水平。在冬季，当空气质量主要来自印度西北部，总示踪剂的质量分数的DHOPA增加，但其浓度下降。应用SOA示踪法估算了这四种前体物的次生有机碳（SOC）。有机碳年均值为0.22 ± 0.29 μ gCm −3，其中生物源有机碳（异戊二烯、单萜和β-卡连素之和）占75%。在夏季，异戊二烯是主要的前体物，其SOC贡献率为81%。在冬季，当生物前体物排放大幅下降时，芳香族有机碳的贡献增加。我们的研究表明，在印度次大陆排放的人为污染物可以被传输到TP，并在远程NC的SOC的影响。
Abstract. Secondary organic aerosol (SOA) affects the earth's radiation balance and global climate. High-elevation areas are sensitive to global climate change. However, at present, SOA origins and seasonal variations are understudied in remote high-elevation areas. In this study, particulate samples were collected from July 2012 to July 2013 at the remote Nam Co (NC) site, Central Tibetan Plateau and analyzed for SOA tracers from biogenic (isoprene, monoterpenes and β-caryophyllene) and anthropogenic (aromatics) precursors. Among these compounds, isoprene SOA (SOAI) tracers represented the majority (26.6 ± 44.2 ng m−3), followed by monoterpene SOA (SOAM) tracers (0.97 ± 0.57 ng m−3), aromatic SOA (SOAA) tracer (2,3-dihydroxy-4-oxopentanoic acid, DHOPA, 0.25 ± 0.18 ng m−3) and β-caryophyllene SOA tracer (β-caryophyllenic acid, 0.09 ± 0.10 ng m−3). SOAI tracers exhibited high concentrations in the summer and low levels in the winter. The similar temperature dependence of SOAI tracers and isoprene emission suggested that the seasonal variation of SOAI tracers at the NC site was mainly influenced by the isoprene emission. The ratio of high-NOx to low-NOx products of SOAI (2-methylglyceric acid to 2-methyltetrols) was highest in the winter and lowest in the summer, due to the influence of temperature and relative humidity. The seasonal variation of SOAM tracers was impacted by monoterpenes emission and gas-particle partitioning. During the summer to the fall, temperature effect on partitioning was the dominant process influencing SOAM tracers' variation; while the temperature effect on emission was the dominant process influencing SOAM tracers' variation during the winter to the spring. SOAM tracer levels did not elevate with increased temperature in the summer, probably resulting from the counteraction of temperature effects on emission and partitioning. The concentrations of DHOPA were 1–2 orders of magnitude lower than those reported in the urban regions of the world. Due to the transport of air pollutants from the adjacent Bangladesh and northeastern India, DHOPA presented relatively higher levels in the summer. In the winter when air masses mainly came from northwestern India, mass fractions of DHOPA in total tracers increased, although its concentrations declined. The SOA-tracer method was applied to estimate secondary organic carbon (SOC) from these four precursors. The annual average of SOC was 0.22 ± 0.29 μgC m−3, with the biogenic SOC (sum of isoprene, monoterpenes and β-caryophyllene) accounting for 75 %. In the summer, isoprene was the major precursor with its SOC contributions of 81 %. In the winter when the emission of biogenic precursors largely dropped, the contributions of aromatic SOC increased. Our study implies that anthropogenic pollutants emitted in the Indian subcontinent could be transported to the TP and have an impact on SOC over the remote NC.
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DOI：
--
发表时间：
2012
期刊：
--
影响因子：
--
作者：
N. Eddingsaas;C. L. Loza;L. Yee;M. Chan;K. Schilling;P. Chhabra;J. Seinfeld;P. Wennberg
通讯作者：
N. Eddingsaas;C. L. Loza;L. Yee;M. Chan;K. Schilling;P. Chhabra;J. Seinfeld;P. Wennberg
影响因子：
11.4
作者：
M. Lewandowski;M. Jaoui;J. Offenberg;T. Kleindienst;E. Edney;R. Sheesley;J. Schauer
通讯作者：
M. Lewandowski;M. Jaoui;J. Offenberg;T. Kleindienst;E. Edney;R. Sheesley;J. Schauer
影响因子：
11.4
作者：
Glasius, M;Lahaniati, M;Larsen, BR
通讯作者：
Larsen, BR
影响因子：
5
作者：
Anna van Eijck;T. Opatz;D. Taraborrelli;R. Sander;T. Hoffmann
通讯作者：
Anna van Eijck;T. Opatz;D. Taraborrelli;R. Sander;T. Hoffmann
影响因子：
11.4
作者：
E. Stone;Jiabin Zhou;D. C. Snyder;A. Rutter;M. Mieritz;J. Schauer
通讯作者：
E. Stone;Jiabin Zhou;D. C. Snyder;A. Rutter;M. Mieritz;J. Schauer