State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, People's Republic of China.
Environ Sci Technol. 2013 Apr 2;47(7):3149-57. doi: 10.1021/es3037093. Epub 2013 Mar 7.
During the 2003 Chinese Arctic Research Expedition (CHINARE2003) from the Bohai Sea to the high Arctic (37°N-80°N), filter-based particle samples were collected and analyzed for tracers of primary and secondary organic aerosols (SOA) as well as water-soluble organic carbon (WSOC). Biomass burning (BB) tracer levoglucosan had comparatively much higher summertime average levels (476 ± 367 pg/m(3)) during our cruise due to the influence of intense forest fires then in Siberia. On the basis of 5-day back trajectories, samples with air masses passing through Siberia had organic tracers 1.3-4.4 times of those with air masses transporting only over the oceans, suggesting substantial contribution of continental emissions to organic aerosols in the marine atmosphere. SOA tracers from anthropogenic aromatics were negligible or not detected, while those from biogenic terpenenoids were ubiquitously observed with the sum of SOA tracers from isoprene (623 ± 414 pg/m(3)) 1 order of magnitude higher than that from monoterpenes (63 ± 49 pg/m(3)). 2-Methylglyceric acid as a product of isoprene oxidation under high-NOx conditions was dominant among SOA tracers, implying that these BSOA tracers were not formed over the oceans but mainly transported from the adjacent Siberia where a high-NOx environment could be induced by intense forest fires. The carbon fractions shared by biogenic SOA tracers and levoglucosan in WSOC in our ocean samples were 1-2 orders of magnitude lower than those previously reported in continental samples, BB emissions or chamber simulation samples, largely due to the chemical evolution of organic tracers during transport. As a result of the much faster decline in levels of organic tracers than that of WSOC during transport, the trace-based approach, which could well reconstruct WSOC using biogenic SOA and BB tracers for continental samples, only explained ∼4% of measured WSOC during our expedition if the same tracer-WSOC or tracer-SOC relationships were applied.
在 2003 年中国北极考察（CHINARE2003）期间，从渤海到高纬度北极（37°N-80°N），采集了基于滤膜的颗粒样品，并对其进行了分析，以寻找原生和次生有机气溶胶（SOA）以及水溶性有机碳（WSOC）的示踪剂。由于当时西伯利亚发生了强烈的森林火灾，在我们的考察期间，夏季生物质燃烧（BB）示踪剂左旋葡聚糖（levoglucosan）的平均水平（476±367pg/m3）相对较高。基于 5 天的后轨迹分析，与仅经过海洋运输的气团相比，经过西伯利亚的气团具有 1.3-4.4 倍的有机示踪剂，这表明大陆排放对海洋大气中的有机气溶胶有实质性贡献。人为芳香族化合物的 SOA 示踪剂可忽略不计或未检测到，而生物萜烯类化合物的 SOA 示踪剂则普遍存在，其中来自异戊二烯的 SOA 示踪剂（623±414pg/m3）比来自单萜的 SOA 示踪剂（63±49pg/m3）高 1 个数量级。2-甲基甘油酸作为在高氮氧化物条件下异戊二烯氧化的产物，是 SOA 示踪剂中的主要成分，这意味着这些 BSOA 示踪剂不是在海洋上形成的，而是主要从相邻的西伯利亚运输而来，在那里，强烈的森林火灾可能导致高氮氧化物环境。海洋样品中生物 SOA 示踪剂与左旋葡聚糖共享的碳分数在 WSOC 中比以前在大陆样品、BB 排放或室模拟样品中报告的低 1-2 个数量级，这主要是由于在运输过程中有机示踪剂的化学演化。由于在运输过程中有机示踪剂的水平下降速度比 WSOC 快得多，因此，基于示踪剂的方法可以很好地利用生物 SOA 和 BB 示踪剂来重建大陆样品中的 WSOC，但如果应用相同的示踪剂-WSOC 或示踪剂-SOC 关系，该方法仅能解释我们考察期间测量的 WSOC 的约 4%。
