道路绿化带影响大气颗粒物分布实测研究

以福州市西三环快速路某路段为实验靶区,利用微型环境检测仪采集路边细颗粒物(PM_2.5)、亚微米颗粒物(PM_1.0)和黑碳(BC)的空间分布样本,解析其在道路绿化带前后(绿化带前是指干道和辅道外边缘线位置,其他位置均视为绿化带后)的变化特征及原因。结果表明：(1)颗粒物浓度随着采样点远离干道而整体趋于递减,呈现BC>PM_2.5>PM_1.0的衰减率变化特征,且植被稠密的路边环境对应更大的颗粒物浓度降幅。(2)夏季绿化带后的颗粒物浓度降幅高于冬季,冬季绿化带后部分采样点的PM_1.0和PM_2.5浓度甚至有所抬升。在植被茂密的路边环境下,风自干道吹向绿化带情景的路边空气质量介于风自绿化带吹向干道情景和风平行于干道情景之间。(3)BC对交通变化的敏感性高于PM_2.5和PM_1.0,植被茂密的绿化带后的颗粒物浓度降幅会因交通强度的上升而增大。风自干道吹向绿化带时,绿化带对颗粒物的调节作用会随交通源强和季节的变化而不同...

Impacts of Road Green Belts on the Distribution of Atmospheric Particulate Matter by Field Measurements

Taking a road section of the West Third Ring Expressway in Fuzhou City as the experimental area,the portable environmental detectors were used to collect the spatial samples of fine particulate matter (PM_2.5),submicron particulate matter (PM_1.0) and black carbon (BC) at roadside,and the variation characteristics of particulate matter before and after road green belts ("before green belts" refers to the outer edge line of the main road or auxiliary road,while other positions are regarded as "after green belts") with potential reasons were analyzed.Results showed that:(1) Atmospheric particles tended to decrease as the sampling point was far away from the main road,with a concentration attenuation rate of BC>PM_2.5>PM_1.0.The roadside environment with denser vegetation indicated a greater reduction in particulate matter concentration.(2) The reduction of particulate matter concentration after the green belt was better in summer than that in winter,and the PM_1.0 and PM_2.5 concentrations at some sampling points after the green belt were even increased in winter.For vegetation-rich areas,when the wind blew from the main road to the green belt,roadside air quality was between those scenarios of wind blowing from the green belt to the main road and being parallel to the main road.(3) BC was more sensitive to traffic changes than PM_2.5 and PM_1.0.In the roadside area covered by dense vegetations,the drop in particulate matter concentration after the green belt could increase due to the increase in traffic intensity.When the wind blew from the main road to the green belt,the regulation effect of the green belt on particulate matter varied with the traffic intensity and seasons.Therefore,a full consideration of roadside greening structures and the main composition of road pollutants as well as their temporal variation,will be more practical in exploring the greening strategies of actively reducing air pollution in road micro-environments.