北京市大兴区道路积尘年际变化特征及管控研究

为探究长时间跨度的道路积尘变化特征，于2019~2020年对北京市大兴区内主要道路进行尘负荷检测，并于2020年四季收集道路PM₁₀和PM_2.5积尘样品，分析化学组分，建立成分谱.结果表明，2019年和2020年大兴区道路尘负荷年均值分别为1.05g/m²和0.74g/m²，2020年大兴区道路尘负荷较2019年下降29.5%.2019年道路尘负荷热点聚集区分散，大兴区内道路尘负荷高值区较多，2020年热点区集中出现在西北部，冷点区集中在东部区域.2020年大兴区道路扬尘排放因子低于2019年，大部分乡镇/街道中，2020年的扬尘排放因子和排放量低于2019年，呈现出东南部 > 中部 > 西北部的趋势.2020年大兴区道路扬尘排放量低于2019年，大兴区南部和西北部乡镇/街道内的扬尘排放量大于中部.受建筑施工活动影响.2020年大兴区道路PM₁₀和PM_2.5积尘化学组分中以土壤风沙和建筑施工活动相关的元素为主，Ca、Mg、Si、Al元素分别共占比39.39%和41.71%.对大兴区道路尘负荷进行针对性管控，首先需要对运输车辆进行及时冲洗，降低轮胎的尘土夹带量.其次应加强工地出口至附近1km的道路清扫保洁频次，将工地出口处道路尘负荷对周边道路的辐射影响降低.

Interannual variation characteristics and control of road dust in Daxing District of Beijing

Based on the detection of silt loadings of main roads in Daxing District of Beijing from 2019 to 2020 and the road dust samples of PM₁₀ and PM_2.5 for the whole year 2020, this study sought to investigate the variation characteristics of long-term road dust accumulation by systematically analyzing the chemical composition and establishing the composition spectrum. The results showed that the annual average silt loadings of Daxing District in 2019 and 2020 was 1.05g/m² and 0.74g/m², respectively. In 2020, the silt loadings in Daxing District decreased by 29.5% compared with that in 2019. In 2019, the hot spots of silt loadings were scattered, and there were more high value areas of silt loadings in Daxing District. In 2020, the hot spots were concentrated in the northwest, while the cold spots were concentrated in the East. The road fugitive dust emission factors in 2020 in Daxing District were lower than those in 2019 and in most subdistricts/towns, the dust emission factors and emissions in 2020 were lower than those in 2019, showing a trend of the southeast > central > northwest. In 2020, the road dust emission in Daxing District was lower than that in 2019 and the dust emission in subdistricts/towns in the south and northwest of Daxing District was higher than that in the middle. Influenced by construction activities, in 2020, the chemical components of road PM₁₀ and PM_2.5 in Daxing District were dominated by elements related to wind-blown sand and construction activities, with Ca, Mg, Si and Al accounting for 39.39% and 41.71%, respectively.For the targeted control of the silt loadings in Daxing District, on the one hand,timely washing of transport vehicles was needed to reduce the dust entrainment amount of tires; on the other hand, the frequency of cleaning of roads from the site exit to the nearby 1km should be enhanced to reduce the radiation effect of silt loadings at the exit of construction site on surrounding roads.