Sources of humic-like substances in the Pearl River Delta, China: positive matrix factorization analysis of PM 2.5 major components and source markers
Sources of humic-like substances in the Pearl River Delta, China: positive matrix factorization analysis of PM 2.5 major components and source markers
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DOI：
10.5194/acp-15-1995-2015
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发表时间：
2014-09
影响因子：
6.3
通讯作者：
B. Kuang;P. Lin;X. Huang;J. Yu
中科院分区：
文献类型：
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作者：
B. Kuang;P. Lin;X. Huang;J. Yu
抽象的。类腐殖物质（HULIS）是水溶性有机碳（WSOC）的疏水部分，占PM2.5质量的很大一部分。到目前为止，他们的源研究主要是定性的。本研究对2009年在珠江三角洲广州市区和南沙郊区采集的100个PM2. 5样品进行了HULIS和WSOC测定。HULIS的年平均浓度分别为4.83和4.71 μg m−3，占PM2.5质量的8.5%和10.2%，而HULIS-C（HULIS的碳组分）分别占两个站点WSOC的48%和57%。发现HULIS与生物质燃烧（BB）示踪剂（即，左旋葡聚糖和K）和次级种类（例如，SO 42 −和NH 4+），表明其与BB排放和次级形成过程有关。采用正矩阵因子分析法对PM2.5化学成分数据进行了HULIS来源分析，包括主要成分和来源标志物。除了二次形成过程和BB排放外，与航运有关的残油燃烧首次被确定为HULIS的重要来源。在不同季节，次生形成过程的贡献最大，占49-82%的环境HULIS在两个地点。BB排放的季节平均贡献率为8- 28%，冬季（11月至2月）由于收获季节的作物残留物燃烧而观察到更多的贡献。残油燃烧被发现是一个重要的来源，在郊区的网站在夏季（44%的HULIS-C），由于其接近该地区的港口和航道之一。车辆排放被认为是贡献不大的HULIS，但有贡献的亲水性WSOC部分。不同燃烧源对HULIS和亲水性WSOC的贡献的对比表明，HULIS的主要来源与低效燃烧有关。因此，今后应重点研究BB和渣油燃烧产生的HULIS的二次形成过程和来源特征。
Abstract. Humic-like substances (HULIS), the hydrophobic part of water-soluble organic carbon (WSOC), account for a significant fraction of PM2.5 mass. Their source studies are so far largely qualitative. In this study, HULIS and WSOC were determined in 100 PM2.5 samples collected in 2009 at an urban site (Guangzhou) and a suburban site (Nansha) in the Pearl River Delta in South China. The annual average concentration of HULIS was 4.83 and 4.71 μg m−3, constituting 8.5 and 10.2% of the PM2.5 mass, while HULIS-C (the carbon component of HULIS) contributed 48 and 57% of WSOC at the two sites, respectively. HULIS were found to correlate with biomass burning (BB) tracers (i.e., levoglucosan and K) and secondary species (e.g., SO42− and NH4+), suggesting its association with BB emissions and secondary formation processes. Sources of HULIS were investigated using positive matrix factorization analysis of PM2.5 chemical composition data, including major components and source markers. In addition to secondary formation process and BB emissions, residual oil combustion related to shipping was identified for the first time as a significant source of HULIS. Secondary formation process contributed the most, accounting for 49–82% of ambient HULIS at the two sites in different seasons. BB emissions contributed a seasonal average of 8–28%, with more contributions observed in the winter months (November–February) due to crop residue burning during harvest season. Residual oil combustion was revealed to be an important source at the suburban site in summer (44% of HULIS-C) due to its proximity to one of the ports and the shipping lane in the region. Vehicle emissions were found to contribute little to HULIS, but had contributions to the hydrophilic WSOC fraction. The contrast in contributions from different combustion sources to HULIS and hydrophilic WSOC suggests that primary sources of HULIS are linked to inefficient combustion. This source analysis suggests further study of HULIS be focused on secondary formation process and source characteristics of HULIS from BB and residual oil combustion.