First Chemical Characterization of Refractory Black Carbon Aerosols and Associated Coatings over the Tibetan Plateau (4730 m a.s.l)
First Chemical Characterization of Refractory Black Carbon Aerosols and Associated Coatings over the Tibetan Plateau (4730 m a.s.l)
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青藏高原（4730 m a.s.l）上难熔黑碳气溶胶和相关涂层的首次化学表征
DOI：
10.1021/acs.est.7b03973
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发表时间：
2017
影响因子：
11.4
通讯作者：
Coe Hugh
中科院分区：
文献类型：
--
作者：
Wang Junfeng;Zhang Qi;Chen Mindong;Collier Sonya;Zhou Shan;Ge Xinlei;Xu Jianzhong;Shi Jinsen;Xie Conghui;Hu Jianlin;Ge Shun;Sun yele;Coe Hugh
难熔黑碳(RBC)气溶胶是一种重要的气候强制物，其影响很大程度上受到与RBC核相关的物种的影响。然而，在青藏高原，相关知识尤其缺乏。本文首次报道了利用Aerodyne烟尘粒子气溶胶质谱仪(SP-AMS)选择性地测量含碳粒子的高时间分辨率测量结果，测量了TP中心(4730ma.s.l)RBC及其涂层物种。结果表明，包覆层整体较厚，平均包覆量为∼7.7，包覆层主要由光化学反应形成。有趣的是，厚层RBC的含氧量低于薄层RBC，这主要是由于运输的生物质燃烧有机气溶胶(BBOA)的影响。这种BBOA比较新鲜，但在RBC上形成了很厚的涂层。我们通过比较多角度吸收光度计和SP-AMS的测量数据，进一步半定量地估计了涂层的“透镜效应”，发现它可以导致RBC>；10的光吸收增强高达40%。我们的发现突出了BBOA除了相对众所周知的吸收光的“棕色碳”作用外，还可以显著影响“透镜效应”。
Refractory black carbon (rBC) aerosol is an important climate forcer, and its impacts are greatly influenced by the species associated withrBC cores. However, relevant knowledge is particularly lacking at the Tibetan Plateau (TP). Here we report, for the first time, highly time-resolved measurement results ofrBC and its coating species in central TP (4730 m a.s.l), using an Aerodyne soot particle aerosol mass spectrometer (SP-AMS), which selectively measuredrBC-containing particles. We found that therBC was overall thickly coated with an average mass ratio of coating torBC (RBC) of ∼7.7, and the coating species were predominantly secondarily formed by photochemical reactions. Interestingly, the thickly coatedrBC was less oxygenated than the thinly coatedrBC, mainly due to influence of the transported biomass burning organic aerosol (BBOA). This BBOA was relatively fresh but formed very thick coating onrBC. We further estimated the “lensing effect” of coating semiquantitatively by comparing the measurement data from a multiangle absorption photometer and SP-AMS, and found it could lead to up to 40% light absorption enhancement atRBC> 10. Our findings highlight that BBOA can significantly affect the “lensing effect”, in addition to its relatively well-known role as light-absorbing “brown carbon.”