Light absorption, fluorescence properties and sources of brown carbon aerosols in the Southeast Tibetan Plateau
Light absorption, fluorescence properties and sources of brown carbon aerosols in the Southeast Tibetan Plateau
复制标题
青藏高原东南部褐碳气溶胶的光吸收、荧光特性及来源
DOI：
10.1016/j.envpol.2019.113616
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发表时间：
2020-02-01
影响因子：
8.9
通讯作者：
Cong, Zhiyuan
中科院分区：
文献类型：
--
作者：
Wu, Guangming;Wan, Xin;Cong, Zhiyuan
棕碳（BrC）由于其光吸收特性，已被认为是气候变化的重要驱动因素。然而，我们对BrC的化学和光学性质的理解是不够的，特别是在偏远地区。本文对青藏高原东南部地区夏季（2013年8月）和冬季（2014年1月）的BrC气溶胶进行了全面的研究。甲醇可溶性BrC（MeS-BrC）的浓度约为水溶性BrC（WS-BrC）的两倍，表明水不溶性BrC的环境重要性以前被低估，仅考虑WS-BrC。WS-BrC的质量吸收效率（0.27-0.86 m2 g-1）低于南亚重污染地区，表明喜马拉雅山两侧的WS-BrC质量吸收效率存在明显差异。荧光光谱分析表明，BrC的吸收主要是由类腐殖酸和类蛋白质物质引起的，这拓宽了目前对BrC发色团的认识。结合有机示踪剂、卫星MODIS数据和气团后向轨迹分析，研究发现夏季BrC主要来源于生物气溶胶和二次生成，而冬季BrC主要来源于生物质燃烧排放的长距离输送。我们的研究为BrC的光学和化学性质提供了新的见解，这可能对环境效应和有机气溶胶的来源具有重要意义。(C)2019爱思唯尔有限公司版权所有。
Brown carbon (BrC) has been proposed as an important driving factor in climate change due to its light absorption properties. However, our understanding of BrC's chemical and optical properties are inadequate, particularly at remote regions. This study conducts a comprehensive investigation of BrC aerosols in summer (Aug. 2013) and winter (Jan. 2014) at Southeast Tibetan Plateau, which is ecologically fragile and sensitive to global warming. The concentrations of methanol-soluble BrC (MeS-BrC) are approximately twice of water-soluble BrC (WS-BrC), demonstrating the environmental importance of water-insoluble BrC are previously underestimated with only WS-BrC considered. The mass absorption efficiency of WS-BrC (0.27-0.86 m(2) g(-1)) is lower than those in heavily polluted South Asia, indicating a distinct contrast between the two sides of Himalayas. Fluorescence reveals that the absorption of BrC is mainly attributed to humic-like and protein-like substances, which broaden the current knowledge of BrC's chromophores. Combining organic tracer, satellite MODIS data and air-mass backward trajectory analysis, this study finds BrC is mainly derived from bioaerosols and secondary formation in summer, while long-range transport of biomass burning emissions in winter. Our study provides new insights into the optical and chemical properties of BrC, which may have implications for environmental effect and sources of organic aerosols. (C) 2019 Elsevier Ltd. All rights reserved.