高速公路路域大气污染特征分析

ANALYSIS OF AIR POLLUTION CHARACTERISTICS IN EXPRESSWAY AREAS

为了解高速公路路域大气污染物的时空分布特征,以张掖市山丹县境内G30连霍高速为研究对象,通过实地监测数据,采用多尺度地理加权回归(MGWR)模型界定出路域大气污染物边界界限的前提下,对监测到的主要污染物(PM_(2.5)、PM_(10)、CO和SO_(2))进行了时空特征分析以及其与交通和气象要素的相关性分析。结果表明:常数项和边界距离对于Isum(环境空气质量综合指数)的影响均呈显著的负向影响,在距离高速公路边界300 m的监测点,常数项中位数为-0.316,边界距离平均值为-1.022,同时距离高速公路边界300 m后常数项和边界距离的回归系数趋于平稳,故将大气污染物的高速公路路域边界界限定义为距离高速公路边界300 m的区域。在相关性分析中,相较于CO和SO_(2)呈与交通量和气象因素的显著相关性,PM_(10)和PM_(2.5)与交通量和气象因素并未呈显著的相关性。风向对于PM_(2.5)、PM_(10)和SO_(2)的空间分布影响较大,但对CO的空间分布并未呈正向的影响。

In order to understand the spatial and temporal distribution characteristics of air pollutants in highway areas,the G30 Lian-huo Highway in Shandan County,Zhangye City was taken as the research object.Based on field monitoring data,multi-scale geographically weighted regression(MGWR)model was used to define the boundary of air pollutants in highway areas.The temporal and spatial characteristics of the main pollutants(PM_(2.5),PM_(10),CO and SO_(2))and their correlation with traffic and meteorological elements were analyzed.The results showed that:The influence of constant term and boundary distance on Isum(a composite index of ambient air quality)was significantly negative.At the monitoring point 300 meters away from the expressway boundary,the median of the constant term was-0.316,and the mean boundary distance was-1.022.Meanwhile,the regression coefficients of a constant term and boundary distance tended to be stable after 300 meters away from the expressway boundary.Therefore,the boundary of air pollutants in the highway domain was defined as the area within a distance of 300 meters from the highway boundary.In correlation analysis,while CO and SO_(2)showed significant correlation with traffic volume and meteorological factors,PM_(10)and PM_(2.5)showed no significant correlation with traffic volume and meteorological factors.The wind direction had a strong influence on the spatial distribution of PM_(2.5),PM_(10)and SO_(2),but didn’t have a positive effect on CO spatial distribution.