基于积尘负荷的西安市铺装道路扬尘排放研究

近年来城市颗粒物污染问题日渐突出，严重影响着人们的环境幸福指数和对美好环境的期待.道路扬尘作为城市扬尘的重要组成部分，对颗粒物污染的贡献不容小觑.在此背景下，采用积尘负荷法采集西安市快速路、主干道、次干道、支路等4种类型25条道路的道路扬尘样品，并分析采样速率、采样次数等因素对采样效率的影响.在此基础上，计算得到西安市各类型道路的平均积尘负荷，结合车流量、车重、道路长度，通过《扬尘源颗粒物排放清单技术指南》中的公式计算得到各种类型道路TSP、PM₁₀、PM_2.5的排放系数及排放量.结果显示：采样速率为1.0 m²·min^-1，采样次数为两次可满足采样要求.不同类型道路积尘顺序为：支路（4.18 g·m^-2）>次干道（2.80 g·m^-2）>快速路（1.49 g·m^-2）>主干路（1.34 g·m^-2）；道路积尘TSP、PM₁₀、PM_2.5的平均排放系数分别为6.066、1.542和0.447 g·km^-1.快速路和主干路的扬尘排放系数较小，支路的扬尘排放系数次之，次干路的扬尘排放系数较大.采用Monte Carlo方法对TSP、PM₁₀和PM_2.5的排放量进行不确定性分析，在95%的概率分布范围下，三者定量不确定性均为-16.88%~17.96%.

Emission characteristics of pavement road dust in Xi'an based on dust load method

In recent years, the problem of urban particulate pollution has become more and more serious, which seriously affects the environmental happiness index and the expectation of a better environment. As a significant part of urban dust, road dust contributes to particulate pollution cannot be underestimated. Based on this fact, the dust load method was used to collect road dust samples from 25 roads of 4 types, including expressways, main roads, secondary roads and branch roads in Xi''an. The effects of sampling rate and sampling frequency on sampling efficiency were analyzed as well. On these data, the average dust load of various types of roads could be calculated in Xi''an. Then, combined with the vehicle flow, vehicle weight and road length, the emission coefficients and emissions of TSP, PM₁₀, PM_2.5 were calculated through the formulas in the "Technical Guidelines for Emission Inventory of Particulate Matter from Dust Sources". The results show that 1.0 m²·min^-1 and the sampling twice can meet the sampling requirements. The order of dust accumulation on different roads is:branch road (4.18 g·m^-2)> secondary road (2.80 g·m^-2)> expressway (1.49 g·m^-2)> main road (1.34 g·m^-2). The average emission factors of TSP, PM₁₀ and PM_2.5 is 6.066 g·km^-1, 1.542 g·km^-1 and 0.447 g·km^-1 respectively. The dust emission factors of expressways and main roads are smaller among different types of road dust, followed by that of branch roads and then secondary roads. The uncertainty of TSP, PM₁₀ and PM_2.5 emissions was analyzed by Monte Carlo method, which shows the uncertainty is -16.88%~17.96% under the probability distribution range of 95%.