城市道路PM_(2.5)浓度的时空变化及地理因子影响分析

Spatial-Temporal Variations of PM_(2.5) Concentration on Urban Roads and the Influence of Geographical Factors

通过移动走航式观测获取长沙市岳麓山周边道路不同通勤时段PM_(2.5)浓度数据,结合土地覆盖、兴趣点、数字高程模型、邻近污染源和街区路网分布5类微环境地理因子,采用空间聚合、空间自相关分析、分位数回归分析等方法,探究研究区内道路PM_(2.5)浓度的时空变化及其与城市微环境地理因子的潜在联系。结果表明,长沙市岳麓山周边道路不同通勤时段PM_(2.5)浓度时空差异明显:晚高峰时段PM_(2.5)中位数浓度高达31.5μg/m^(3),早高峰和非高峰时段分别为28.2μg/m^(3)和22.0μg/m^(3);高值PM_(2.5)浓度在通勤高峰时段空间分布相对集中,在非高峰时段则相对分散。就地理因子影响而言:不同通勤时段影响PM_(2.5)浓度的微环境地理因子在数量与类别上存在差异;同时,微环境地理因子对不同分位数道路PM_(2.5)浓度的影响也具有异质性。依据各通勤时段不同地理因子的影响趋势和影响程度,采取相应的针对性调控、空间合理配置等干预策略有望全面降低道路PM_(2.5)浓度。本研究可为基于空气质量视角的城市空间规划与开发建设调控提供科学依据。

In this paper,PM_(2.5) concentration on the roads around Yuelu Mountain in Changsha in different commuting hours was obtained by mobile navigation monitoring,and the spatiotemporal variation characteristics of the on-road PM_(2.5) concentration were explored through the semi-variogram spatial aggregation method and spatial autocorrelation analysis.Meanwhile,the quantile regression model was adopted to study the influence of geographical factors(land cover,POI,DEM,nearby pollution sources and block street distribution)on PM_(2.5) concentration.The results showed that there were significant spatiotemporal differences of PM_(2.5) concentration in various commuting hours.The median concentration of PM_(2.5) was the highest in evening rush hours(31.5μg/m^(3)),followed by 28.2μg/m^(3) in morning rush hours and 22.0μg/m^(3) in off-peak hours.The spatial distribution of high PM_(2.5) concentration was relatively concentrated in rush hours,but relatively dispersed in off-peak hours.In terms of the influence of geographical factors,there were differences in the number and category of geographical factors affecting PM_(2.5) concentration in various commuting hours.Meanwhile,the influence of geographical factors on PM_(2.5) concentration with different quantile was also heterogeneous.According to the influence trend and degree of different geographical factors in various commuting hours,the on-road PM_(2.5) concentration was expected to be comprehensively reduced through targeted regulation,reasonable spatial allocation and other intervention policies.This study could provide a scientific basis for urban spatial planning,developing construction from the perspective of air quality.