Assessment of street dust is an invaluable approach for monitoring atmospheric pollution. Little information is available on the size distribution of contaminants in street dusts and urban soils, and it is not known how the population density would influence them. This research was carried out to assess the size distribution of trace metal(loid)s in street dust and urban soil, and to understand how population density might influence the size-resolved concentration of metal(loid)s. Three urban areas with a high, medium and low population density and a natural area were selected and urban soil and street dust sampled. They were fractionated into 8 size fractions: 2000–850, 850–180, 180–106, 106–50, 50–20, 20–10, 10–2, and < 2 µm. The concentration of Pb, Zn, Cu, Cd, Cr, Ni, As, and Fe was determined, and enrichment factor and grain size fraction loadings were computed. The results indicated that the concentration of Pb, Zn, Cu, Cd, and Cr was highly size dependent, particularly for particles < 100 µm, especially for street dust. Low concentrations of Ni and As in street dust and urban soil were size and population density independent. Higher size dependency of the metals concentration and the higher degree of elemental enrichment in the street dust fractions than the urban soils indicate higher contribution of human-induced pollution to the dust. Findings also confirm the inevitability of size fractionation when soils or dusts are environmentally assessed, particularly in moderately to highly polluted areas. Otherwise, higher concentrations of certain pollutants in fine-sized particles might be overlooked leading to inappropriate decisions for environmental remediation.

评估街道灰尘是监测大气污染的一种宝贵方法。关于街道尘土和城市土壤中污染物的大小分布的信息很少，而且人口密度将如何影响它们尚不知道。这项研究旨在评估街道尘土和城市土壤中痕量金属（胶体）的大小分布，并了解人口密度如何影响金属（胶体）的尺寸分辨浓度。选择了三个人口密度高，中，低的城市区域和一个自然区域，并对城市土壤和街道灰尘进行了采样。它们分为8个大小部分：2000–850、850–180、180–106、106–50、50–20、20–10、10–2和<2 µm。确定了Pb，Zn，Cu，Cd，Cr，Ni，As和Fe的浓度，并计算出富集系数和晶粒度分数负荷。结果表明，Pb，Zn，Cu，Cd和Cr的浓度高度依赖于尺寸，特别是对于<100 µm的颗粒，尤其是街道灰尘。街道粉尘和城市土壤中低浓度的镍和砷与大小和人口密度无关。与城市土壤相比，街道尘埃中金属浓度的大小依赖性更高，元素富集度更高，这表明人为污染对尘埃的贡献更大。研究结果还证实，当对土壤或粉尘进行环境评估时，尤其是在中度污染至高污染地区，尺寸分级是不可避免的。除此以外，