基于季节性污染特征的大气VOCs化学活性及源解析
Chemical activity and source apportionment of atmospheric volatile organic compounds based on seasonal pollution characteristics
谢非 1白宇婷 2田永莉 3李亮 3周兴军 3吕昌伟4
作者信息
- 1. 内蒙古大学生态与环境学院,呼和浩特,010021;内蒙古自治区环境监测总站,呼和浩特,010011
- 2. 内蒙古大学生态与环境学院,呼和浩特,010021
- 3. 内蒙古自治区环境监测总站,呼和浩特,010011
- 4. 内蒙古大学生态与环境学院,呼和浩特,010021;内蒙古大学环境地质研究所,呼和浩特,010021
- 折叠
摘要
挥发性有机物(VOCs)是对流层大气氧化性的重要影响因子,不同VOCs物种的化学反应活性与大气环境质量及污染过程关系密切.本文针对呼和浩特和包头采暖期长达半年的季节特征,选取冬夏季清洁天、污染天和沙尘天的不同时间窗口,识别并分析了两个城市大气中117种VOCs的体积浓度,计算了不同季节不同大气特征条件下不同VOCs物种的化学反应活性,并解析了两个城市大气VOCs的来源.结果表明,乙烯、乙醛、丙烷、丙烯、丙醛、正丁醛、异戊二烯、甲苯、间/对二甲苯等是两个城市大气的主要活性VOCs物种;不同大气特征条件下不同VOCs物种对OFP(臭氧生成潜势)和LOH(羟自由基反应速率)的影响差异较大,且影响大小并不单独依赖于各VOCs物种浓度;2个城市冬季大气中的O3对VOCs的浓度变化更敏感,夏季则对NOx的浓度变化更敏感,体现了这两个城市O3前体物的季节性差异;受季节特征及供暖方式的影响,2个城市冬季燃烧源排放约贡献大气VOCs的50％,机动车排放和LPG/NG源次之;与冬季相比,夏季机动车、生物源及LPG/NG、溶剂挥发等因子的重要性显著提升,而燃烧源因子的比重明显下降,意味着大气VOCs源具有显著的季节变化特征.本研究对准确辨析区域重污染天气特征与成因,实现"十四五"期间PM2.5与臭氧协同控制等意义重大.
Abstract
As an important factor affecting the oxidizing capacity of the tropospheric atmosphere,the chemical reactivity of different volatile organic compounds(VOCs)species is closely related to atmospheric environmental quality and pollution processes.In this work,the seasonal characteristics,chemical reactivity and source apportionment were discussed based on an observation of 117 species of VOCs during different periods(e.g.,clean,polluted and dust period,respectively)both in summer and winter in Baotou and Hohhot.The results showed that propane,ethylene,propylene,isoprene,acetaldehyde,formaldehyde,n-butylaldehyde,toluene and xylene were the key reactive VOCs species of the two cities.Under different atmospheric conditions,the effects of VOCs on OFP(ozone formation potential)and LOH(hydroxyl radical reaction rate)significantly varied with their species and are not only dependent on the concentration of VOC species.It was found that the concentrations of O3 in the two cities were highly sensitive to VOCs and NOx in winter and summer,respectively,indicating the seasonal difference in O3 precursors.Influenced by heating events during winter,combustion sources contributed to approximately 50％ of atmospheric VOCs,followed by vehicle exhaust and LPG/NG(Liquefied Petroleum Gas/Natural Gas)sources.Compared to winter,the importance of factors such as vehicle exhaust,biogenic,LPG/NG and solvent sources significantly increases in summer,while the proportion of combustion sources decreases significantly,indicating the significant seasonal variability of atmospheric VOC sources.This study is significant in accurately distinguishing the characteristics and causes of severe regional air pollution,and achieving joint control of PM2.5 and O3 during the"14th Five-Year Plan"period.
关键词
VOCs/季节特征/物种组成/反应活性/来源解析Key words
volatile organic compounds/seasonal pattern/species composition/reactivity/source apportionment引用本文复制引用
基金项目
内蒙古自治区科技重大专项(2020ZD0013)
国家自然科学基金(41763014)
内蒙古自治区"青年科技人才支持计划"A类"青年科技领军人才"(NJYT2022092)
出版年
2024
NETL
NSTL
万方数据