祝 颖1a,b，罗静期1a,b，刘焕武2，沈振兴3，李业鑫4，刘言正5，周 勇1a,b
1. 西安建筑科技大学 a. 环境与市政工程学院; b. 陕西省环境工程重点实验室，陕西 西安 710055；
2. 西安市环境监测站, 陕西 西安 710061；
3. 西安交通大学 能源与动力工程学院，陕西 西安 710049；
4. 安康市环境工程设计有限公司，陕西 安康 725000；
5. 西安建筑科技大学 南澳大学安德学院，陕西 西安 710311
DOI:10.13732/j.issn.1008-5548.2021.06.005
收稿日期： 2021-04-11，修回日期：2021-07-09，在线出版时间：2021-10-18 14:25。
基金项目：国家重点研发计划项目，编号：2016YFC0207800；国家自然科学基金，编号：51608422；陕西省大学生创新创业训练计划项目，编号：S201910703084；陕西省一流专业建设项目，编号：YLZY0303C02。
第一作者简介：祝颖(1984—)，女(蒙古族)，博士，副教授，硕士生导师，研究方向为大气污染控制。E-mail：zhuyingxauat@163.com。
摘要：为研究2019新型冠状病毒疫情期间细颗粒物(PM2.5)化学组分及来源,于2020年1月1日—2020年3月31日,利用在线监测仪器对西安市北郊PM2.5化学组分进行连续观测。结果表明:NO3-、SO42-、NH4+是水溶性离子中最主要的成分,且水溶性离子呈中性偏碱性;相比新冠疫情管控前(PC),新冠疫情严管期(DC)的PM2.5、CO、SO2、NOX、元素碳、NO3-及SO42-的质量浓度降幅分别为10.56%、21.89%、13.40%、65.98%、9.54%、29.69%和10.04%,且NO3-与SO42-质量浓度比值降幅为29.41%;通过有机碳与元素碳质量浓度比值分析,含碳组分物质主要来自于燃煤和机动车尾气源;二次有机碳是逐渐复工期(GW)、全面复工期(AW)有机碳的主要来源,一次有机碳是PC、DC阶段有机碳的主要来源;通过正定矩阵因子分解法源解析结果表明,PC、DC、GW阶段首要污染源为燃煤源(64.00%),AW阶段建筑及扬尘贡献值最大(61.34%),原因是管控措施DC阶段机动车源减少3.20%,工业工艺源减少1.82%。
关键词：新冠疫情；细颗粒物；水溶性离子；碳组分；源解析
Abstract：In order to study the chemical characteristics of PM2.5 during the COVID-19 pandemic,this study used online observation instruments to continuously observe chemical components of PM2.5 in the northern urban area of Xi'an from 01 January to 31 March,2020. The results show that NO3-,SO42-,NH4+are the most important components of water-soluble ions,and the watersoluble ions are neutrality skew alkaline. Compared with pre-COVID-Lockdown stage(PC),the mass concentrationsof PM2.5,CO,SO2,NOX,elemental carbon,NO3-,SO42-are reduced by 10. 56%,21. 89%,13. 40%,65. 98%,9. 54%,29. 69%and 10. 04% respectively in COVID-Lockdown stage(DC),and the mass concentration ratio of NO3-and SO42-is reduced by 29. 41%. The mass concentration ratio of organic carbon to elemental carbon reveals that the carbon component in the measurement period mainly come from coal and vehicle exhaust sources. The estimation of the secondary organic carbon found that the secondary organic carbon is the main source of gradual resumption of work(GW) and almost complete resumption of work(AW) stages,and primary organic carbon is the main source of PC and DC stages. Positive matrix factorization source analysis results show that coal combustion(accounting for 64. 00%) is the main source of organic carbon in PC,DC and GW stages,and the contribution value of construction and dust in AW stage is the largest(61. 34%). Due to the control measures,the motor vehicle source in DC stage decreases by 3. 20%,and the industrial process source decreases by 1. 82%.
Keywords：COVD-19 pandemic; PM2.5; water-soluble ions; carbonaceous; source
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