城市森林大气PM_(2.5)中水溶性无机离子沉降特征  

Dry deposition of water-soluble inorganic ions in PM_(2.5) above urban forest

作　　者：莫莉[1,5] 郑文革 李仁娜 李丹[3] 邸林栓 李小勇 伦小秀[3] 马伟芳[3] MO Li;ZHENG Wenge;LI Renna;LI Dan;DI Linshuan;LI Xiaoyong;LUN Xiaoxiu;MA Weifang(School of Soil and Water Conservation,Beijing Forestry University,Beijing,100083,China;Beijing Water and Soil Conservation Work Station,Beijing,100036,China;College of Environmental Science and Engineering,Beijing Forestry University,Beijing,100083,China;The School of Economics and Management,Beijing Forestry University,Beijing,100083,China;Technical Centre for Soil,Agriculture and Rural Ecology and Environment,Ministry of Ecology and Environment,Beijing,100012,China)

机构地区：[1]北京林业大学水土保持学院,北京100083 [2]北京市水土保持工作总站,北京100036 [3]北京林业大学环境科学与工程学院,北京100083 [4]北京林业大学经济管理学院,北京100083 [5]生态环境部土壤与农业农村生态环境监管技术中心,北京100012

出　　处：《环境化学》2021年第3期746-753,共8页Environmental Chemistry

基　　金：北京市科技项目(Z181100005318003,Z201100008220013);国家自然科学基金(42077454)资助.

摘　　要：森林被誉为"地球之肺",在防霾治污方面有其独特不可替代的作用,不同树种沉降PM_(2.5)的功能有很大差别.本文选取代表性城市森林——奥林匹克森林公园为研究对象,设置垂直监测塔观测大气PM_(2.5)的浓度垂直分布,以考察不同季节城市森林对PM_(2.5)中各组分的影响.在冬季、春季和夏季各采集PM_(2.5)样品,分析并计算PM_(2.5)中Na^(+)、NH_(4)^(+)、K^(+)、Mg2^(+)、Ca2^(+)、Cl^(-)、NO_(3)^(-)和SO_(4)^(2-)等典型水溶性无机离子的浓度.结果表明,PM_(2.5)中水溶性无机离子总浓度呈规律性变化特征:冬季((56.90±27.38)μg·m-3)>春季((46.69±12.24)μg·m^(-3))>夏季((23.16±8.75)μg·m^(-3)).其中SO_(4)^(2-)和NO_(3)^(-)浓度和占PM_(2.5)主要水溶性无机离子总浓度的50%以上.3个季节中,除冬季外,在春季和夏季,8种离子有明显的垂直方向上的沉降,夏季的沉降速率高于春季,但是春季由于大气颗粒物浓度高,沉降通量高于夏季.NO_(3)^(-)和SO_(4)^(2-)垂直方向的沉降量在所有可溶性无机离子中最高.植被密度、叶面积指数、气象条件等因素对于PM_(2.5)的沉降特征有明显影响.As the"lung of the earth",forests play a unique and irreplaceable role in haze prevention and pollution control.Different tree species have different functions in settling PM_(2.5).In this paper,Olympic Forest Park,a representative urban forest,was selected as the research object,and a vertical monitoring tower was set up to observe the vertical distribution of atmospheric PM_(2.5)concentration,so as to investigate the impact of urban forests in different seasons on the components of PM_(2.5).The PM_(2.5)samples were collected in winter,spring and summer,and the concentrations of typical water-soluble inorganic ions such as Na^(+),NH_(4)^(+),K^(+),Mg^(2+),Ca^(2+),Cl^(-),NO_(3)^(-)and SO_(4)^(2-)in PM_(2.5)were analyzed and calculated.The results showed that the total concentration of water-soluble inorganic ions in PM_(2.5)showed regular changes:((56.90±27.38)μg·m^(-3))>in winter((46.69±12.24)μg·m-3)>in summer((23.16±8.75)μg·m^(-3)).The concentration of SO_(4)^(2-)and NO_(3)^(-)accounted for more than 50%of the total concentration of major water-soluble inorganic ions in PM_(2.5).In the three seasons,except for winter,8 kinds of ions had obvious vertical deposition in spring and summer.The deposition rate in summer was higher than that in spring,but the precipitation flux in spring was higher than that in summer due to the high concentration of atmospheric particles.The vertical deposition of NO_(3)^(-)and SO_(4)^(2-)was the highest among all soluble inorganic ions.Vegetation density,leaf area index(LAI),meteorological conditions and other factors have a significant impact on the dry deposition characteristics of PM_(2.5).

关 键 词：城市森林 PM_(2.5) 水溶性无机离子 沉降 森林树冠层 

分 类 号：X513[环境科学与工程—环境工程]