摘要
亚洲沙尘是全球沙尘的重要组成部分,中国西北部的戈壁沙漠和黄土高原是亚洲主要的沙尘源区之一,通过远距离传输至我国沿海城市及海洋,可能影响着城市空气质量、海洋初级生产力及全球气候系统.2021年3月,中国西北地区共发生3次沙尘暴事件.后向轨迹表明沙尘期气团主要起源于萨雷耶西克阿特劳沙漠、塔克拉玛干沙漠(古海洋性沙漠)等.为了解中国西北沙尘暴期间PM_(2.5)水溶性离子(WSIs)特征及来源分析,本研究于3月在宁夏中卫市某乡镇采集了PM_(2.5)样品,并测定了其水溶性离子.结果显示,沙尘期和非沙尘期离子浓度存在较大的差异,沙尘期总WSIs浓度为(45.8±18.1)μg·m^(−3),远高于非沙尘期的总WSIs浓度(29.7±12.8)μg·m^(−3),约为非沙尘期的2倍.其中SO_(4)^(2−)、Ca^(2+)、Na^(+)、NH_(4)^(+)是沙尘期和非沙尘期PM_(2.5)中主要的4种离子,占比分别为81.8%和77.9%.通过相关性及化学计量关系分析得出,沙尘期PM_(2.5)中WSIs来源主要以自然来源(地壳土壤风化以及海盐)为主;非沙尘期除自然来源外,还可能受煤燃烧及机动车尾气等人为二次来源的影响.运用潜在源贡献因子分析法(PSCF)和浓度权重轨迹分析法(CWT),分析了沙尘期与非沙尘期中卫市PM_(2.5)总水溶性离子浓度潜在源区及其对研究区WSIs的贡献.结果表明,沙尘期潜在源区主要分布在中卫市的西北一带,权重浓度超过30μg·m^(−3).非沙尘期主要受中卫市周边地区及西北一带的叠加影响,中卫市周边地区权重浓度超过30μg·m^(−3).
Asian dust is an important component of global dust,and the Gobi Desert and loess Plateau in northwest China are the main sources of dust in Asia,which can be exported to coastal cities and oceans by long-distance transport and affect urban air quality,marine primary productivity and global climate system.In March 2021,three sandstorm events occurred in northwest China.The backward track indicated that the air mass originated from the Sarexik Atrau desert and the Taklimakan desert(ancient maritime desert).To understand the characteristics and sources of watersoluble ions(WSIs)in PM_(2.5)during sandstorms in northwest China.PM_(2.5)samples were collected in a township in Zhongwei,and the water-soluble ion concentrations were measured.The results showed that there is a great difference in ion concentration between dust and non-dust periods,and the WSIs concentration in dust period was(45.8±18.1)μg·m^(−3),much higher than the WSIs in nondust period(29.7±12.8)μg·m^(−3),the concentration in dust period was about twice of that in non-dust period.SO_(4)^(2−),Ca^(2+),Na^(+),NH_(4)^(+)are the four main ions in PM_(2.5)in dust period and non-dust period,accounting for 81.8%and 77.9%,respectively.Through correlation and stoichiometric analysis,the main WSIs sources of PM_(2.5)in dust period are natural sources(crust soil weathering and sea salt).In addition to natural sources,non-dust period may also be affected by secondary sources,such as coal combustion and motor vehicle exhaust.Potential source contribution factor analysis(PSCF)and concentration weight trajectory analysis(CWT)were used to analyze the potential source areas of WSIs their contribution to WSIs in the study area during dust and non-dust periods.The results show that the potential source area of dust period is mainly distributed in the northwest of Zhongwei,and the weight concentration is more than 30μg·m^(−3).The non-dust period is mainly influenced by the superposition of the surrounding area of Zhongwei and the northwest area,and the weighted concentration of the surrounding area of Zhongwei is more than 30μg·m^(−3).
作者
马艳
肖红伟
黄莉磊
艾文强
陈振平
肖扬宁
李智滔
陶继华
MA Yan;XIAO Hongwei;HUANG Lilei;AI Wenqiang;CHEN Zhenping;XIAO Yangning;LI Zhitao;TAO Jihua(Jiangxi Province Key Laboratory of the Causes and Control of Atmospheric Pollution,East China University of Technology,Nanchang,330013,China;School of Environmental Science and Engineering,Shanghai Jiaotong University,Shanghai,200240,China;School of Geosciences,East China University of Technology,Nanchang,330013,China;School of Water Resources and Environmental Engineering,East China University of Technology,Nanchang,330013,China)
出处
《环境化学》
CAS
CSCD
北大核心
2022年第10期3299-3309,共11页
Environmental Chemistry
基金
国家自然科学基金(42063001,41663003)
江西省科技计划项目(2017BCD40010)
江西省大气污染成因与控制重点实验室开放基金(AE2108)资助.
关键词
沙尘暴
PM_(2.5)
水溶性离子
组成特征
来源解析
宁夏
Sandstorm
PM_(2.5)
Water-soluble ions
Composition characteristics
Source apportionment
Ningxia
作者简介
通信联系人:肖红伟,E-mail:xiaohw@sjtu.edu.cn。
