【摘要】 城市近地面环境与人呼吸带高度范围相当,近地面大气颗粒物对行人健康有直接影响。当常规环境监测点位置和数量不足以全面反映近地表大气颗粒物空间分布状况时,选择合适的颗粒物载体显得十分必要。植物叶片的滞尘效应使之成为大气颗粒物的良好指标,尤其是常绿灌木叶片更能直接反映近地表环境悬浮颗粒物状况。以大气颗粒物污染严重的代表性城市石家庄市为研究区域,选择道路绿篱灌木大叶黄杨,于连续晴朗干燥天气条件下采集了3个5d周期内、63处样点的滞尘叶片样品,测试叶片滞尘量和滞尘颗粒物粒度,利用ArcGIS讨论叶片滞尘量和滞尘颗粒粒度的空间分布及空间变异特征。结果显示,石家庄市大叶黄杨叶片平均滞尘量为0.3843g·m-2·d-1(变化于0.0931~0.9155g·m-2·d-1),滞尘颗粒物粒度均值为1.9185μm(变化于1.3067~2.2500μm),98.27%的颗粒小于10μm,表明大叶黄杨叶片在城市近地表环境中对可吸入颗粒物有较好滞留性能,对行人呼吸健康有益。空间变异性分析表明,大叶黄杨叶片滞尘量和滞尘颗粒物粒度均具有空间自相关性,其中滞尘颗粒物粒度的块金值/基台值更小,即空间自相关性更强,表明滞尘颗粒物尺度除受局地污染源影响外,叶片表面属性因素起更重要作用;而滞尘量相对较大的块金值说明局地小尺度过程的影响不容忽视,即更易受到局地起尘源的影响。通过PM1、PM2.5、PM5、PM10等不同粒级颗粒物的分析表明,颗粒物越细其空间分布差异越大,这种细颗粒物的空间变化为进一步探讨城市不同地区人对大气颗粒物的暴露风险研究提供了基础。更多还原

【Abstract】 The atmospheric dust suspended near ground level in urban environment can influence human health directly and analyz-ing the particle space distribution is important. When the routine ambient air quality monitoring sits number is limited to give enough data, relaying on the plants leaves can be a good method to study space distribution of suspended particles near ground. Here we chose the representative brush plant -Euonymus Japonicus Thumb as the agent in the typical air polluted city of Shijiazhuang to exam the dust uptake amount on the leaves’ surface and space variation. 63 samples had been collected under clear and dry weather for 3 five-days periods. The dust uptake capacity was measured by filtration and the particle size was measured by the Particle Size and Shape Analyzer (CIS-50). The results show that the average dust capacity on the leaves of is 0.384 3 g·m-2·d-1 (0.093 1~0.915 5 g·m-2·d-1), the average mean size of the particle on the leaves surface is 1.918 5 μm (1.306 7~2.250 0 μm) with 98.27% of the parti-cles less than 10μm, demonstrating the effective capture for the fine particle of the leaves, which should be beneficial to pedestrian health. The space analysis by geo-statistic method indicates that both of the dust capacity and particle size on leaves surface have good special structures, meaning a certain space autocorrelation. The ratio of nuggets to sill for the particle size is smaller compared with those of the dust capacity, implying that particle captured is influenced by the leaf surface features besides of the local dust sources. And the dust capacity on leaf is controlled mostly by the local sources. The finer the particle size is, the more variational the suspended particle distributes, based on the analysis to the number percent of PM1, PM2.5, PM5, and PM10. The space distribution of dust capacity and particle size on the leaves of Euonymus Japonicus Thumb has provided reference for the risk research on human exposure to particulate matter in urban.更多还原