Changes in shape and composition of sea-salt particles upon aging in an urban atmosphere
Changes in shape and composition of sea-salt particles upon aging in an urban atmosphere
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DOI：
10.1016/j.atmosenv.2014.10.036
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发表时间：
2015-01-01
影响因子：
5
通讯作者：
Buseck, Peter R.
中科院分区：
文献类型：
--
作者：
Adachi, Kouji;Buseck, Peter R.
海盐是天然气溶胶颗粒中含量最丰富的类型之一，对当地和全球气候都有重大影响。这是2010年CalneX竞选期间6月10日至15日在洛杉矶地区收集的样本的重要组成部分。海盐粒子与大气中的其他物种发生反应，形成含钠气溶胶(NAA)粒子。使用透射电子显微镜，我们发现几乎一半的被分析粒子(类似于3500)中存在Na，尽管通常只有少量。几乎所有的NAA颗粒物中都含有S，但不含有氯，这表明在城市大气中，氯通过颗粒形成被耗尽为硫酸盐和硝酸盐，或两者兼而有之。我们观察到圆形和正面体NAA颗粒。圆形的主要是陈年的海盐(>；12h)，它与硫酸盐发生了广泛的反应，而真面体的则出现在相对新鲜的海洋空气中。城市大气中NAA颗粒的形态和组成在3h内发生了变化。此外，我们的计算表明，NAA颗粒的光散射取决于它们的形状(例如，大致球形、扁平或细长)。这些成分和形状分别影响吸湿性和光散射，这两者都会影响它们的气候效应。(C)2014爱思唯尔有限公司。保留所有权利。
Sea salt is one of the most abundant types of natural aerosol particles and significantly influences local and global climate. It is an important constituent of samples collected between June 10 and 15 in the Los Angeles area during the 2010 CalNex campaign. The sea-salt particles reacted with other species in the atmosphere and became Na-bearing aerosol (NaA) particles. Using transmission electron microscopy, we found that Na occurred in almost half of all analyzed particles (similar to 3500), although commonly only in minor amounts. Almost all the NaA particles contained S but not Cl, suggesting that Cl was depleted through particle formation to sulfate, nitrate, or both in the urban atmosphere. We observed both rounded and euhedral NaA particles. The rounded ones consisted mainly of aged sea salt (>12 h) that had reacted extensively with sulfate, whereas the euhedral ones occurred in samples from relatively fresh marine air. The shapes and compositions of NaA particles changed within 3 h in the urban atmosphere. Moreover, our calculations indicate that light scattering from NaA particles depends on their shapes (e.g., roughly spherical, flat, or elongated). These compositions and shapes affect hygroscopicities and light scattering, respectively, both of which influence their climate effects. (C) 2014 Elsevier Ltd. All rights reserved.