西安市大气降尘污染时空分异特征  

Spatial and Temporal Variation of Atmospheric Deposition Pollution in Xi'an City

作　　者：杨文娟[1] 陈莹[1] 赵剑强[1] 胡博[1] 

机构地区：[1]长安大学环境科学与工程学院,旱区地下水文与生态效应教育部重点实验室,陕西西安710054

出　　处：《环境科学与技术》2017年第3期10-14,共5页Environmental Science & Technology

基　　金：国家自然科学基金项目(51308050);中央高校基本科研业务费专项资金资助项目(CHD2011JC114)

摘　　要：在西安市位于工业区、商业区、居民文教区和旅游区的4处国家环境空气质量控制点设置大气降尘采样器,用湿法逐月收集2014年度大气降尘样品并测试降尘量,采用ICP-MS法测试4点位各季大气降尘混合样品重金属Pb、Zn、Cu、Cr、Ni、Cd的含量,研究大气降尘量及大气降尘重金属污染水平及时空分异特征。结果表明,西安市大气降尘污染严重,工业区、商业区、居民文教区、旅游区降尘量年均值分别为17.84、15.99、15.46和11.76 t/(km^2·(30 d)),远超国外相关标准;大气降尘量季节变化显著,表现为冬季>春季>夏季>秋季,各功能区降尘量除秋季差异不显著外,其余各季差异明显,且表现出工业区最大,商业区、居民文教区次之,旅游区最小的趋势;大气降尘重金属Pb、Zn、Cu、Cr、Ni、Cd质量浓度均值分别为438.1、454.9、61.1、149.5、41.4和7.8 mg/kg,分别是陕西省土壤背景值的20.5、6.6、2.9、2.4、1.4和83.0倍,Pb、Cr、Cd污染严重,富集显著;除Pb、Zn季节变化不显著外,Cu、Cd、Ni显著呈现冬季最高、春季次之、夏秋季最小的季节变化特征,Cr表现为冬季最高、其余季节较小;受城市功能区区分不明显及高空大气环流作用影响,西安市大气降尘重金属空间差异不显著。In order to investigate the dustfall flux, heavy metal pollution condition, spatial and temporal variation of atmospheric deposition in Xi＇an City, samples were wet collected at four control points of national ambient air quality located in industrial zone, commercial zone, cultural and educational zone and scenic zone month by month in 2014. The concentration of heavy mental such as Pb, Zn, Cu, Cr, Ni and Cd was tested with ICP-MS simultaneously. The results indicated that the atmospheric deposition pollution in Xi＇an was serious. The annual average dustfall flux in industrial zone, commercial zone, cultural and educational zone and scenic zone was 17.84 t/（kmz＂ （30 d））, 15.99 t/（km2＂ （30 d））, 15.46 t/ （km2＂（30 d））, 11.76 t/（km2 ＂（30 d））, much higher than foreign related standard. Dust fall flux changed with seasons significantly, with the affected order as winter〉spring〉summer〉autumn. Dustfall flux also varied in studied function zones greatly except in autumn, with the largest quantity in industrial zone , then in commercial and cultural and educational ones, the smallest in scenic zone. Furthermore, the average concentration of Pb, Zn ,Cu ,Cr, Ni, Cd in atmospheric deposition was 438.1 mg/kg, 454.9 mg/kg, 61.1 mg/kg, 149.5 mg/kg, 41.4 mg/kg and 7.8 mg/kg respectively, which was 20.5, 6.6, 2.9, 2.4, 1.4 and 83.0 times of the soil background value in Shaanxi Province. Pollution of Pb, Cr, Cd was serious and distinctly enriched. Concentration of Pb and Zn did not dynamically change with seasons, while the concentration of Cu, Cd, Ni was highest in winter, lowest in summer and autumn. Concentration of Cr in winter was much higher in other seasons. Spatial variation of heavy metal concentration in dustfall in Xi＇an was not significant due to the indistinguishable partition of functional zones and upper air circulation.

关 键 词：大气降尘 大气降尘量 重金属 时空分异特征 单因素方差分析 

分 类 号：X51[环境科学与工程—环境工程]