天津市近地層pm25的垂直分布特征-資料下載頁(yè)
2025-08-17 09:19本頁(yè)面
【正文】 ary Boundary Layer on Urban Air Pollutants: Measurements from a 250 meter tower over Tianjin, China[J]. Journal of Hazardous Materials, 2008, doi:/Vertical Distribution of the at the Ground Layer in TianjinHan Suqin1,2, Li Peiyan2, Li Xiangjin2, Sun Meiling21. Collage of Environmental Science and Engineering, Nankai University, Tianjin 300071, China。2. Tianjin meteorology institute, Tainjin 300074, ChinaAbstracts: The pollution caused by atmospheric particulate is one of the important factors affecting urban visibility, research on the vertical distributive characters of at the ground layer is benefit for the understanding the formation mechanism of the primary pollutants, which will provide a new scientific basis for the prehensive pollution control. Experiments were carried out from 16, Aug of 2006 to 31,Aug of 2007 on the meteorological tower of 255 m height in Tianjin. The observation of mass concentration with the meteorological elements at three levels of 40 m, 120 m and 220 m are analyzed. The major results are showed as follows: Firstly, seasonal variations of are significant, which is the greatest in winter, and the smallest in spring. Secondly, daily variation of at each level is also significant, with two obvious peaks observed. The winter peak is higher in magnitude than in spring . Thirdly, the concentration at each level in the boundary layer is markedly different. Affected by the nocturnal inversion layer, the time of first peak occurring in the morning in four seasons have an obvious lag. It needs about 2 hours for the ’s expanding from the surface to 220 m height. The mass concentration at different height varies little with wind direction, So, a conclusion is drawn the particulate pollution in Tianjin is mainly caused by local source emissions. Key words: 。 ground layer of the atmospheric。 vertical distribution。 height of the nocturnal mixing layer
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