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林业科学 ›› 2016, Vol. 52 ›› Issue (12): 74-83.doi: 10.11707/j.1001-7488.20161209

• 论文与研究报告 • 上一篇    下一篇

基于洗脱称量粒度分析的北京常见树种树叶滞纳大气颗粒物特性

刘同彦, 纪媛, 蒋春晓, 邵鹏, 李海英, 贾黎明   

  1. 城乡生态环境北京实验室 北京林业大学省部共建森林培育与保护教育部重点实验室 北京 100083
  • 收稿日期:2016-05-13 修回日期:2016-06-14 出版日期:2016-12-25 发布日期:2017-01-16
  • 通讯作者: 贾黎明
  • 基金资助:
    北京市科委项目“首都平原百万亩造林科技支撑工程”(Z121100008512002);北京市级大学生创新项目(S201410022012)。

Characterization of the Retention of Atmospheric Particulates by Leaves of Common Tree Species in Beijing Based on Elution-Weighing-Particle Size-Analysis

Liu Tongyan, Ji Yuan, Jiang Chunxiao, Shao Peng, Li Haiying, Jia Liming   

  1. Beijing Laboratory of Urban and Rural Ecological Environment Key Laboratory for Silviculture and Conservation of Ministry of Education Beijing Forestry University Beijing 100083
  • Received:2016-05-13 Revised:2016-06-14 Online:2016-12-25 Published:2017-01-16

摘要: [目的] 比较树木叶片和塑料叶片单位面积滞纳细颗粒物(PM2.5)、可吸入颗粒物(PM10)、总悬浮颗粒物(TSP)等大气颗粒物的量,从而区分出受树木叶片结构影响的滞尘量(DRLS)和不受叶片结构影响的滞尘量(DULS),为探索城市树木缓解大气颗粒物污染的贡献及优化树种配置提供科学依据。[方法] 以北京市常用的6个绿化树种为对象,持续测定4个季度的叶片滞尘动态,以没有降雨影响的10天为1个试验周期,进行本底采样和颗粒物积累采样,并设置光滑塑料叶片(由自摩擦系数为0.04的聚四氟乙烯塑料制成)对照试验模拟DULS,对采集到的供试样本叶片(含树木叶片和塑料叶片)采用洗脱称量粒度分析法(EWPA),测定10天内各树种叶片单位面积滞尘总量、DULS和对不同粒径颗粒物的滞纳量。[结果] 1)滞尘能力最强的侧柏单位叶面积总滞尘量为(124.76±19.27)μg·cm-2,是滞尘能力最低的元宝枫的2.24倍,其对PM2.5的滞纳量为(16.92±2.61)μg·cm-2。2)DULS占树木叶片滞尘总量的比例仅为19.65%~42.29%,DRLS所占比例为57.71%~80.35%。3)侧柏的DRLS能力最强,占其滞尘总量80.35%;元宝枫的DRLS能力最弱,占其滞尘总量57.71%;供试针叶树种和阔叶树种的DRLS占滞尘总量的百分比均值分别为77.42%和63.96%。4)针叶树滞纳的各粒级颗粒物中,PM2.5占滞尘总量的13.83%±0.19%,粒径大于10 μm的颗粒物占56.82%±1.07%;阔叶树滞纳的各粒级颗粒物中,PM2.5占滞尘总量的8.09%±0.94%,粒径大于10 μm的颗粒物占70.29%±3.56%。[结论] 树木叶片对大气颗粒物的滞纳具有特异性且作用效果极为显著;供试树种中针叶树滞尘能力显著高于阔叶树,针叶树对小粒径颗粒物滞纳能力较强,而阔叶树对大粒径颗粒物滞纳能力较强。本研究证明绿化树种对缓解大气颗粒物污染有贡献,为合理选择缓解大气颗粒物污染的树种提供科学依据。

关键词: 洗脱称量粒度分析法(EWPA), 大气颗粒物, PM2.5, 树木叶片, 叶片结构性滞尘

Abstract: [Objective] The difference between real and plastic leaves in the retention of fine particles (PM2.5),inhalable particles (PM10),total suspended particulates(TSP) and other atmospheric particulates was studied to distinguish ‘dust-retention related to leaf structures(DRLS)’ and ‘dust-retention unrelated to leaf structures(DULS)’. This study provides a scientific basis to explore the contribution of trees to alleviating the pollution of atmospheric particulates and to optimize the configuration of different tree species.[Method] Six typical afforestation tree species of Beijing were selected for the study. Dynamic foliage absorption was continuously detected for the four quarters of a year, baseline samples and leaf samples with accumulated particles were collected in a ten-day rainless period. Besides, the smooth plastic leaves(made of PTFE, friction coefficient is 0.04)were used as control to simulate the DULS and elution-weighing-particle size-analysis (EWPA) was used to measure the amount of dust adhesion per unit area of each tree species, DULS and the retaining amount of different sizes of particles within the 10 days.[Result] 1) Platycladus orientalis had the strongest dust detention. The total retention amounts per unit leaf area of P. orientalis was (124.76±19.27) μg·cm-2, 2.24 times of the lowest retention by Acer truncatum with (16.92±2.61) μg·cm-2. 2) DULS accounted for only 19.65%-42.29% of total dust-retention, while DRLS accounted for 57.71%-80.35%. 3) P. orientalis had the strongest ability of DRLS, comprising 80.35% of the total stagnation. While A. truncatum had the weakest retention ability and its DRLS accounted for 57.71% of the total dust. DRLS of conifer species made up 77.42% of the total dust-retention on average while broadleaf species accounted for 63.96%. 4) Among the different size classes of particles retained by conifer species, PM2.5 accounted for 13.83%±0.19% of total and PM10 accounted for 56.82%±1.07%. Among various sizes of particles retained by broadleaf species, PM2.5 accounted for 8.09%±0.94% of total dust and PM10 accounted for 70.29%±3.56%.[Conclusion] Tree leaves play a specific and significant role in retaining atmospheric particulates. The ability of dust adhesion of conifer species tested was significantly higher than that of the broadleaf species. The conifers was strong in retaining small particles in the atmosphere, while the broadleaf trees was better in retaining big particles. The study proved that afforestation species makes great contribution to pollution alleviation of atmospheric particulates and provides a scientific basis for a reasonable choice of tree species to mitigate atmospheric particle pollution.

Key words: elution-weighing-particle size-analysis (EWPA), atmospheric particulate matter, PM2.5, tree leaves, dust-retention related to leaf structures

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