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道路下垫面是街尘累积-冲刷这一城市地表径流发生核心过程的重要场所,研究道路下垫面粗糙度对街尘及其负载污染物的持留分布与污染特征将对估算地表径流负荷及控制策略提供重要科学依据.本文以典型沥青和混凝土路面的街尘为研究对象,采样配对法试验设计并结合分形理论,对比分析粗糙度对街尘单位面积含量、颗粒物粒径组成、负载的氮磷及重金属污染的影响.结果表明,相比沥青路面,粗糙度较小的水泥路面所持留的颗粒物单位面积含量较少,颗粒物粒径较细,分选性较好.氮、磷含量与2种下垫面的粗糙度并无显著的相关关系,主要受环境因素影响较大,各粒径的氮、磷含量负荷比与其质量比一致,细粒径颗粒物对氮、磷的吸附作用并不明显.而重金属污染则受2种下垫面的粗糙度影响较大,水泥路面重金属含量高于沥青路面,且细粒径颗粒物的重金属污染负荷比较大,高于其质量比2.4%~24.1%.不同下垫面街尘样品各粒径段颗粒物微观形态相似.破损路面对街尘累积过程的单位面积含量及粒径组成有着较大的影响,可能对街尘累积冲刷过程及污染物富集存在不同程度的影响.
The underlying surface of the road is the accumulation of street dust - an important site for scouring the core process of surface runoff in this city. Studying the distribution and pollution characteristics of street surface dust and its load pollutants by the roughness of the road surface will help to estimate the surface runoff load and Control strategy to provide an important scientific basis.In this paper, the typical asphalt and concrete pavement street dust as the object of study, sampling and matching test design and combined with fractal theory, comparative analysis of roughness dust per unit area, particle size composition, load of nitrogen Phosphorus and heavy metal pollution.The results show that compared with the asphalt pavement, the cement surface with smaller roughness retained less content per unit area and smaller particle size, There was no significant correlation between the roughness of the underlying surface and the ground surface, which was mainly affected by environmental factors. The loading ratio of nitrogen and phosphorus was consistent with the mass ratio of each particle size. The adsorption of nitrogen and phosphorus by fine particle size particles was not While the heavy metal pollution is greatly affected by the roughness of the two kinds of underlying surface, the content of heavy metals in cement pavement is higher than asphalt pavement, and the heavy metal pollution of fine particle size particles The load is relatively large, higher than its mass ratio of 2.4% ~ 24.1% .Different underlaid surface dust particles in each particle size section of the microscopic morphology is similar to damaged road surface accumulation of dust per unit area content and particle size composition is larger May affect the process of accumulating street dust and the enrichment of pollutants in varying degrees.