天津市挥发性有机物污染特征与来源及其O3生成潜势

为深入了解天津市大气挥发性有机物(VOCs)来源及对O₃的影响,基于2020年天津市VOCs在线监测数据,统计分析了VOCs污染特征,用主成分分析法对天津市VOCs的来源进行解析,用最大增量反应活性法分析VOCs的O₃生成潜势(OFP)。结果表明:2020年天津市VOCs的年均质量浓度总和为56.56μg/m³,其中,前10的物种分别为丙烷、乙烷、正丁烷、乙烯、甲苯、异戊烷、异丁烷、间/对二甲苯、正戊烷、苯,其年均质量浓度之和为37.83μg/m³,占VOCs总浓度的66.88%;主成分分析结果表明,汽车排放、轻工业溶剂的使用及挥发、石化工业排放、液化石油气/天然气的使用是天津市VOCs的主要来源;天津市VOCs主要组分对OFP的贡献中,烯烃对OFP贡献最高,贡献率为68.65%;芳香烃次之,贡献率为22.47%。

Pollution characteristics and sources of volatile organic compounds and their O3 formation potential in Tianjin

In order to deeply understand the sources of volatile organic compounds(VOCs)in Tianjin and their impact on O₃,based on the online observation data of VOCs in Tianjin in 2020,the pollution characteristics of VOCs were statistically analyzed,and the sources of VOCs in Tianjin were analyzed by principal component analysis.The O₃ formation potential(OFP)of VOCs was analyzed by maximum incremental reactivity method.The results showed that the total annual average concentration of VOCs in Tianjin in 2020 was 56.56μg/m³.The concentration of the top 10 species were propane,ethane,n-butane,ethylene,toluene,isopentane,isobutane,m/p-xylene,n-pentane,benzene,the sum of annual average concentration was 37.83μg/m³ and accounted for 66.88%of the total concentration of VOCs.The results of the principal component analysis showed that the main sources of VOCs were vehicle emissions,the use and volatilization of light industry solvents,petrochemical industry emission,the use of liquid petroleum gas/natural gas in Tianjin.Among the main components of VOCs in Tianjin,the contribution of olefins to OFP was the highest,with a contribution rate of 68.65%,and aromatic hydrocarbons were the second largest,with a contribution rate of 22.47%.