Hygroscopic growth and CCN activity of HULIS from different environments
Hygroscopic growth and CCN activity of HULIS from different environments
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DOI：
10.1029/2012jd018249
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发表时间：
2012-11
影响因子：
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通讯作者：
T. Kristensen;H. Wex;Bettina Nekat;J. Nøjgaard;D. Pinxteren;D. Lowenthal;L. Mazzoleni;K. Dieckmann;C. Koch;T. Mentel;H. Herrmann;A. Hallar;F. Stratmann;M. Bilde
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文献类型：
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作者：
T. Kristensen;H. Wex;Bettina Nekat;J. Nøjgaard;D. Pinxteren;D. Lowenthal;L. Mazzoleni;K. Dieckmann;C. Koch;T. Mentel;H. Herrmann;A. Hallar;F. Stratmann;M. Bilde
[1]腐殖类物质（HULIS）是不同环境中气溶胶颗粒的重要组成部分。对HULIS在气溶胶粒子吸湿增长和云凝结核（CCN）活动中的作用的研究很少，结果差异很大。在这项工作中的吸湿增长和CCN活性的水提取物（WE）和HULIS提取的颗粒物（PM）收集在污染的城市网站（哥本哈根，丹麦），农村网站（梅尔皮茨，德国）和偏远的网站风暴峰实验室（科罗拉多，美国）进行了调查。无机离子，元素碳，有机碳和水溶性有机碳（WSOC）的PM内的测量证实，气溶胶粒子的来源最有可能不同的三个样本。城市、农村和偏远地区WE样品的吸湿特性的特征在于，在亚饱和条件下的吸湿参数（κGF）分别为0.25、0.41和0.22，在过饱和条件下的吸湿参数κCCN分别为0.23、0.29和0.22。三种HULIS样品的吸湿生长和CCN活性几乎相同，分别可用κGF = 0.07和κCCN = 0.08-0.10表示。HULIS样品中存在少量无机离子，因此预计纯HULIS的实际值略低（κGF* = 0.04-0.06和κCCN* = 0.07-0.08）。因此，与大多数以前的研究相比，HULIS样品的吸湿性较低。为了帮助直接比较不同研究中HULIS的吸湿性能，我们建议始终测量和报告HULIS样品中无机物质的分数。
[1] Humic-like substances (HULIS) constitute a significant fraction of aerosol particles in different environments. Studies of the role of HULIS in hygroscopic growth and cloud condensation nuclei (CCN) activity of aerosol particles are scarce, and results differ significantly. In this work the hygroscopic growth and CCN activity of water extracts (WE) and HULIS extracted from particulate matter (PM) collected at a polluted urban site (Copenhagen, Denmark), a rural site (Melpitz, Germany) and the remote site Storm Peak Laboratory (Colorado, USA) were investigated. Measurements of inorganic ions, elemental carbon, organic carbon and water soluble organic carbon (WSOC) within the PM confirmed that the sources of aerosol particles most likely differed for the three samples. The hygroscopic properties of the filtered WE were characterized by hygroscopicity parameters for subsaturated conditions (κGF) of 0.25, 0.41 and 0.22, and for supersaturated conditions κCCN were 0.23, 0.29 and 0.22 respectively for the urban, rural and remote WE samples. The measured hygroscopic growth and CCN activity were almost identical for the three HULIS samples and could be well represented by κGF = 0.07 and κCCN = 0.08–0.10 respectively. Small amounts of inorganic ions were present in the HULIS samples so the actual values for pure HULIS are expected to be slightly lower (κGF* = 0.04–0.06 and κCCN* = 0.07–0.08). The HULIS samples are thus less hygroscopic compared to most previous studies. To aid direct comparison of hygroscopic properties of HULIS from different studies, we recommend that the fraction of inorganic species in the HULIS samples always is measured and reported.