Local Air Pollution Versus Short-range Transported Dust Episodes: A Comparative Study for Submicron Particle Number Concentration
Local Air Pollution Versus Short-range Transported Dust Episodes: A Comparative Study for Submicron Particle Number Concentration
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DOI：
10.4209/aaqr.2010.08.0066
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发表时间：
2011-04
影响因子：
4
通讯作者：
T. Hussein;R. A. Al-Ruz;T. Petäjä;H. Junninen;Dia-Eddin Arafah;K. Hämeri;M. Kulmala
中科院分区：
文献类型：
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作者：
T. Hussein;R. A. Al-Ruz;T. Petäjä;H. Junninen;Dia-Eddin Arafah;K. Hämeri;M. Kulmala
我们测量了2009年春季安曼-约旦城市/郊区大气中的亚微米粒子数浓度。主要目的是区分有/无粉尘事件的亚微米颗粒数浓度的差异。在没有沙尘发作的情况下，浓度表现出明显的日常模式，这是相似的，在城市和城市大气中的浓度较低（至少1：2）在郊区网站。首五个工作日（星期六至星期三）的每日模式与星期四或星期五的模式不同。在早高峰时段，市区和郊区的浓度分别高达120×10^3和75×10^3 1/cm ^3。在这两个地点，这些浓度分别是背景条件下观察到的浓度（午夜至清晨之间为5.5×10^3 1/cm^3）的21倍和14倍。这表明交通排放是安曼城市/郊区大气的主要来源之一。在城市站点，来自附近高速公路的亚微米气溶胶粒子数浓度随风速呈指数下降。在一次沙尘暴期间，亚微米颗粒物的总数浓度约为无沙尘暴工作日期间通常观察到的浓度的1/5。这里的浓度较低归因于两个原因：风速增加和当地排放的城市颗粒与区域尘埃颗粒凝结。在没有沙尘事件的情况下，这些观测结果与其他针对人口稠密城市的研究结果吻合得很好。这项研究的局限性是缺乏有关粒子数尺寸分布的信息，可以揭示安曼气溶胶粒子的模态结构。
We measured the submicron particle number concentrations in the urban/suburban atmosphere of Amman-Jordan during the spring of 2009. The main objective was to distinguish the differences in the submicron particle number concentrations with/without dust episodes. In the absence of dust episodes the concentrations showed distinguished daily patterns, which were similar at both the urban and the urban atmosphere with lower concentrations (at least 1:2) at the suburban site. The daily pattern during the first five working days (Saturday-Wednesday) was different than that that on either Thursday or Friday. During the morning rush hours the number concentrations were as high as 120×10^3 and 75×10^3 1/cm^3 at the urban and suburban sites during those workdays, respectively. These concentrations were about 21 and 14 times what was observed during the background conditions (5.5×10^3 1/cm^3 between midnight and early morning) at both sites. This suggests that traffic emissions are one of the main sources in the urban/suburban atmosphere of Amman. The number concentration of submicron aerosol particles, which originated from the nearby highway, at the urban site decreased exponentially with the wind speed. During a dust episode the total number concentration of submicron particles was about 1/5 of what is typically observed during workdays without dust episodes. The lower concentrations were attributed here for two reasons: increased wind speed and coagulation of locally emitted urban particles with the regional dust particles. These observations in the absence of dust episodes agree well with other studies for highly populated cities. The limitation of this study is the lack of information about the particle number size distribution that can reveal the modal structure of aerosol particles in Amman.