污染控制技术及原理
刘春华,岑况.北京市街道灰尘粒度特征及其来源探析[J].环境科学学报,2007,27(6):1006-1012
北京市街道灰尘粒度特征及其来源探析
- Particle size characteristics and possible sources of street dust in Beijing
- 基金项目：
- 作者
- 单位
- 刘春华
- 1. 中国地质大学地质过程与矿产资源国家重点实验室, 北京 100083; 2. 中国地质大学岩石圈构造、深部过程及探测技术教育部实验室, 北京 100083
- 岑况
- 1. 中国地质大学地质过程与矿产资源国家重点实验室, 北京 100083; 2. 中国地质大学岩石圈构造、深部过程及探测技术教育部实验室, 北京 100083
- 摘要：对北京市2005年4月和11月2次采集的街道灰尘样品进行了粒度分析.结果表明,北京市街道灰尘粒度呈双峰分布特征,第一众数为45～100μm,第二众数为5～20μm,平均粒径分别为75μm(春季)和100μm(秋季);峰态中等偏窄且不对称,分选差,属轻亚粘土到中亚粘土,与黄土和现代尘暴降尘的粒度分布模式相似;街道灰尘沉积是由大气环流对远、近不同距离粗细颗粒物的混合搬运的结果,应是风积作用的继续.街道灰尘样品秋季平均粒径较大,且有由北西至南东逐渐减小的趋势,而春季样品无此变化特点.道路及建筑物工地附近样品呈现大于250μm的第三众数,可以看出大规模的建设对街道灰尘的贡献.在适当的大气动力条件下,北京市街道灰尘颗粒有60%～80%可以进入大气悬浮搬运.
- Abstract：Particle size analysis of street dust collected in April and November, 2005 in Beijing shows a bimodal distribution spectrum, where the first mode is 45～100μm and the second 5～20μm. The average particle sizes were 75μm(in Apr.)and 100μm (in Nov.). The middling to narrow kurtosis, asymmetrical frequency curves and the poor sorting are similar to the particle size distribution of loess and of modern dust storms, which indicates that street dust is a mixture of coarse particles derived from local area and fine particles transported over long distances from the west and west-north of Beijing, and is derived from aeolian processes. The average particle size of street dust was greater in autumn and displayed a decreasing trend from north-west to south-east, but not in the samples after a slight duststorm in April, 2005. Athird mode appears in sampling sites near road and building construction sites, which shows the contribution of extensive construction to street dust. Under proper aerodynamic conditions, 60%～80% of the street dust particles are picked up and transported by suspension.
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