Anthropogenic Calcium Particles Observed in Beijing and Qingdao, China
Anthropogenic Calcium Particles Observed in Beijing and Qingdao, China
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DOI：
10.1007/s11267-005-0743-y
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发表时间：
2005-12
期刊：
影响因子：
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通讯作者：
Daizhou Zhang;G. Shi;Y. Iwasaka;Min Hu;J. Zang
中科院分区：
文献类型：
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作者：
Daizhou Zhang;G. Shi;Y. Iwasaka;Min Hu;J. Zang
对在中国北方北京收集到的单个颗粒物的分析表明，富含钙（Ca）的颗粒物始终构成城市大气中矿物质颗粒的很大一部分。颗粒的特征在于立方形态。颗粒中的主要矿物元素是Ca，几乎没有检测到其他矿物元素。大量颗粒直径<1μm，一般天然矿物颗粒很少检出。在非沙尘暴期间，Ca颗粒对总矿物颗粒体积的贡献大大超过其他矿物颗粒，与沙尘暴期间相当。试剂膜测试表明，Ca 颗粒上硫酸盐和硝酸盐颗粒的形成与普通矿物颗粒上的类似。这些结果表明，北京大气颗粒物中的Ca很大一部分来自人为来源而非自然来源，人为Ca颗粒是硫酸盐和硝酸盐形成的重要介质。中国北方沿海城市青岛也检测到了类似的颗粒。沙尘暴事件的数据显示，来自中国东部的富含Ca的颗粒到达那里并移出大陆，与亚洲沙尘暴颗粒类似，这表明即使在下游地区的亚洲沙尘暴样本中也可能存在人为Ca的贡献。因此，Ca 可能不是天然来源的亚洲沙尘的良好指标。然而，钙颗粒由于其独特的形状和元素组成，可以为东亚地区人为颗粒物的大气扩散提供指标。
Analysis of individual particles collected at Beijing in northern China revealed that particles abundant in calcium (Ca) always constituted a large fraction of mineral particles in the urban atmosphere. The particles were characterized by cubic morphologies. The major mineral element in the particles was Ca and few or no other mineral elements were detected. A large number of the particles were in the range of diameter <1 μm, where common natural mineral particles were rarely detected. The contribution of the Ca particles to the volume of total mineral particles greatly exceeded that of other mineral particles during non-dust-storm periods and was comparable to that during dust-storm periods. Reagent film tests showed that particulate sulfate and nitrate formation on the Ca particles was similar to that on common mineral particles. These results indicate that a large portion of Ca in the atmospheric particulate matter in Beijing was from anthropogenic sources rather than from natural sources, and the anthropogenic Ca particles acted as a significant medium for the formation of sulfate and nitrate. Similar particles were also detected at Qingdao, a coastal city in northern China. Data of a dust storm event showed that Ca-abundant particles from East China arrived there and moved out of the continent, similarly to Asian dust storm particles, suggesting possible contributions of anthropogenic Ca even in Asian dust storm samples in the downstream areas. Therefore, Ca may not be a good indicator of Asian dust from natural sources. However, the Ca particles, due to their unique shapes and elemental compositions, may provide an indicator for the atmospheric dispersion of anthropogenic particulate matters in East Asia.