摘要
为定量云水和云下冲刷分别对降水中SO4^2-、NO3^-的贡献,并进一步解析云下冲刷颗粒相和气相物质分别对降水样品中SO4^2-、NO3^-的贡献,于2016年4月—2017年2月采用APS-3A型降水自动采样仪对降水进行分段采集.采用离子色谱检测分段降水样品的ρ(SO4^2-)、ρ(NO3^-),分析其变化规律;在降水前、降水中及降水后同步采集并检测大气颗粒相ρ(SO4^2-)、ρ(NO3^-)和气相ρ(SO2)、ρ(NO2),分析颗粒相中ρ(SO4^2-)、ρ(NO3^-)和气相中ρ(SO2)、ρ(NO2)的变化与分布.结果表明:①ρ(SO4^2-)、ρ(NO3^-)在同一场降水的分段样品中呈逐渐降低至后期趋于平稳的趋势,说明降水对空气中污染物的冲刷使空气逐渐清洁,后期冲刷作用有限使得降水中离子质量浓度趋稳.②颗粒相中ρ(SO4^2-)、ρ(NO3^-)与气相中ρ(SO2)、ρ(NO2)在降水前较高,在降水中减小,并在降水后回升,说明降水对颗粒相SO4^2-、NO3^-和气相SO2、NO2均有清除作用,降水结束后无云下冲刷作用,污染物质量浓度逐步回升.③云水对降水中ρ(SO4^2-)、ρ(NO3^-)的贡献率分别为22%~56%(平均值为35%)、9%~49%(平均值为29%),云下冲刷颗粒相SO4^2-、NO3^-对降水中ρ(SO4^2-)、ρ(NO3^-)的贡献率分别为39%~69%(平均值为55%)、43%~73%(平均值为56%),云下冲刷气相SO2、NO2对降水中ρ(SO4^2-)、ρ(NO3^-)的贡献率分别为5%~17%(平均值为10%)、5%~19%(平均值为15%).研究显示,降水中SO4^2-、NO3^-主要来源于云水和云下冲刷颗粒相SO4^2-、NO3^-,而来源于云下冲刷气相SO2、NO2较少.
In order to quantify the contribution of cloud water and rain wash-out below the clouds to SO4^2-and NO3^-in wet precipitation and further to differentiate the contribution of scavenging SO4^2-and NO3^-in particulates and of scavenging SO2 and NO2 in the air below the clouds to SO4^2-and NO3^-in wet precipitation,the segmented wet precipitation were collected by APS-3A precipitation automatic samplers from April 2016 to February 2017.Theρ(SO4^2-)andρ(NO3^-)in segmented wet precipitation were detected by ion chromatography and then the variations were analyzed.SO4^2-and NO3^-in particulates and SO2 and NO2 in the air before rainfall,during rainfall and after rainfall were synchronously monitored.Then we analyzed variation ofρ(SO4^2-)andρ(NO3^-)in particulates andρ(SO2)andρ(NO2)in the air before rainfall,during rainfall and after rainfall.The results showed:(1)During the same wet precipitation process,theρ(SO4^2-)andρ(NO3^-)in segmented precipitation decreased gradually and tended to be steady in the final stage of wet precipitation,which illustrated that the wet precipitation scoured the atmospheric pollutants and kept the air clean gradually and that scour effect of the rain became limited,leading to stable ofρ(SO4^2-)andρ(NO3^-)in later wet precipitation period.(2)The mass concentrations of SO4^2-and NO3^-in particles,and the mass concentrations of SO2 and NO2 in the air were the highest before rain;they decreased during rain,and increased after rain,illustrating that the wet precipitation could scavenge SO4^2-and NO3^-in particulates and SO2 and NO2 in the air;but the concentrations of those pollutants increased slightly without the effects of rain wash-out after rain.(3)The contributions to SO4^2-and NO3^-in wet precipitation ranged from 22%to 56%,with an average of 35%,and from 9%to 49%,with an average of 29%.The contributions to SO4^2-and NO3^-in wet precipitation of SO4^2-and NO3^-in particulates scavenged below the clouds ranged from^39%to 69%,with an average of 55%,and from 43%to 73%,with an ave
作者
谭叶玲
邹长伟
黄虹
魏宸
TAN Yeling;ZOU Changwei;HUANG Hong;WEI Chen(Key Laboratory of Poyang Lake Environment and Resource Utilization,Ministry of Education,School of Resources Environmental and Chemical Engineering,Nanchang University,Nanchang 330031,China;Research Institute No.270 China National Nuclear Corporation,Nanchang 330200,China)
出处
《环境科学研究》
EI
CAS
CSCD
北大核心
2019年第12期2098-2107,共10页
Research of Environmental Sciences
基金
国家自然科学基金项目(No.41265009,41765009)~~
