福州市主干道分车绿带对骑行通勤者暴露于细颗粒物的影响

The Impacts of Roadside Green Belts on the Cyclists’Exposure Concentration of Particulate Matters on Urban Street of Fuzhou

选取福州市主城区常见的4种干道分车绿带作为研究对象,采用骑行方式移动监测绿带两侧颗粒物浓度,评估绿带对细颗粒物(PM_(1),PM_(2.5),PM_(10))骑行通勤者暴露浓度的削减作用及影响因素。结果表明:1)道路绿带前后骑行的暴露浓度均高于大气背景浓度,不同绿带对颗粒物的削减效应呈现差异性,乔木与灌木树篱混合型绿带相对突出,其中灌木树篱起到关键性作用;2)较为茂密的路侧绿带会与分车绿带形成郁闭度较高的骑行空间,会降低绿带的削减能力;3)在软风以下及平行风和垂直风(吹向绿带)的气象条件下,有利于提升灌木树篱及乔灌混合型绿带对颗粒物的削减作用,但风速较大(>1.5 m/s)时,会使绿植叶片与骑行车道路面积尘扬起,造成绿带削减率降低;4)为降低骑行通勤暴露的颗粒物浓度,建议乔木与灌木混合型的分车绿带为城市主干道配置方式,并适当提升灌木树篱的高度、宽度和种植密集度,注重对非机动车道路面和绿带的清洁,同时要适当增加路侧绿带与分车绿带的距离并提高乔木的修剪强度,促进骑行区域颗粒物的消散。

The influence of roadside green belts(RGBs)on the reduction of the concentration of particulate matters(PM_(1),PM_(2.5),PM_(10))exposed to cyclist commuters were investigated by cycling mobile measurement in four kinds of common RGBs in Fuzhou urban area.The results showed that 1)The cycling exposure concentrations in front and back of the cyclist were generally higher than the background concentration,and the reduction effect on exposure concentrations showed significant changes between different RGBs.2)The spaces formed between the RGB that separates motor vehicle road and cycling lane and dense RGB on the right side of cycling lane could reduce the particulate matter reduction function of RGB.3)Soft wind and parallel&vertical wind(toward the green belt)were beneficial to improve the reduction of particulate matter for shrub hedges and arbor-shrub mixed green belts,but higher wind speed(>1.5 m/s)would cause the dust re-suspension from green plants and the cycling lanes,resulting in a decrease of the green belt reduction rate.4)In order to reduce the cyclists’exposure concentration of particulate matters,the mixed trees-shrubs green belt was recommended in busy urban roads with the increase of the height,width and planting density of the hedgerow.Cleaning the cycle lanes and plants leaf surface,widening spaces between the trees outside the road and RGBs,and strengthening the tree pruning could also promote the reduction of exposure concentrations.