北京市道路扬尘时空变化特征的研究

Research on temporal-spatial variation characteristics of road dust in Beijing City

道路扬尘已成为城市颗粒物重要来源之一。为了甄选有效的采样测试方法,分别采用降尘法和积尘负荷法对北京市4种不同类型的道路扬尘进行采集,通过分析获得降尘量和积尘负荷的时空变化规律。结果显示:降尘量夏季明显高于秋季,在次干道和支路上,采样高度1.5、2.5m的降尘量差异不大,在夏季差值分别为0.193 0、0.122 4g/(m^2·d),在秋季差值分别为0.037 1、0.013 3g/(m^2·d);而主干道和快速路上,1.5 m高度的降尘量明显大于2.5 m高度,在夏季差值分别为0.268 6、0.464 6g/(m^2·d),在秋季差值分别为0.111 0、0.353 9g/(m^2·d);道路积尘负荷夏季高于秋季,在夏季表现为支路>次干道>主干道>快速路,其积尘负荷从大到小依次为2.758 9、1.976 7、1.787 8、1.547 5g/m^2,在秋季表现为次干道>支路>快速路>主干道,其积尘负荷从大到小依次为1.920 2、1.822 9、1.430 6、0.201 5g/m^2。随着车流量增大和车速加快,积尘负荷逐渐降低。研究结果能为北京市在道路扬尘采样方法的选择和颗粒物控制上提供理论依据。

Road dust has been an important source of urban particulate matter.In order to select effective sampling method,the temporal-spatial variation characteristics of four kinds of road dust in Beijing was focused on,by fall dust and dust load method,respectively.The temporal-spatial variation regular of fall dust and dust load were obtained through laboratory analysis.The results showed that fall dust in summer was significantly higher than it in autumn.In secondary road and branch road,there was no significant difference in fall dust at sampling height of 1.5and 2.5m,with the difference in summer 0.193 0,0.122 4g/（m2·d）,and in autumn 0.037 1,0.013 3g/（m2·d）.However,the fall dust at 1.5m was clearly higher than 2.5min main road and freeway,with the difference in summer 0.268 6and0.464 6g/（m2·d）,and in autumn 0.111 0and 0.353 9g/（m2·d）.Dust load in summer was higher than autumn.In summer,dust load of different sampling roads showed branch road〉secondary road〉main road〉freeway,with their dust load 2.758 9,1.976 7,1.787 8and 1.547 5g/m2,respectively.In autumn,dust load of different roads displayed secondary road〉branch road〉freeway〉main road,with their dust load 1.920 2,1.822 9,1.430 6and 0.201 5g/m2,respectively.Dust load gradually decreased as the traffic volume and speed increasing.The research provided theoretical basis for the choice of road dust sampling method and particulate matter control in Beijing City.