宿迁市VOCs污染特征和来源解析

Characteristics and source apportionment of ambient VOCs in Suqian,China

利用2019年8—9月宿迁市4个站点的采样资料,分析了宿迁大气中挥发性有机物(VOCs)的化学组成及其时空分布特征;估算了VOCs的臭氧生成潜势(OFP);并结合PMF受体模型,开展了VOCs来源解析.结果表明,观测期间宿迁市总挥发性有机物(TVOCs)体积分数为8.6×10^(-9)~79.4×10^(-9),平均体积分数为26.9×10^(-9),浓度水平较低.VOCs质量浓度表现为乡镇工业区(宿迁技师学院:(29.8±18.4)×10^(-9))>城郊工业区(生态化工园:(28.4±20.6)×10^(-9))>城市住宅区(宿迁中学:(22.6±11.5)×10^(-9))>城市商业区(市供电局:(22.3±15.1)×10^(-9)).各采样点4种组分(烷烃、烯烃、乙炔及芳香烃)日均浓度变化较为一致,且均表现出较为明显的周末效应.宿迁市典型污染物为C_(2)~C_(5)烷烃、乙炔、乙烯、甲苯,间/对⁃二甲苯,不同采样点的关键组分基本相同,表明VOCs的来源比较稳定.OFP计算表明芳香烃和烯烃是臭氧最大贡献源.特征量比值分析发现,观测期间宿迁市VOCs有明显老化现象.源解析表明交通排放、溶剂涂料和工业过程是宿迁市VOCs的主要来源.

A two⁃month measurement of volatile organic compounds(VOCs)at the four sites in Suqian was conducted during August to September in 2019.The composition anddistribution characteristics of VOCs were analyzed based on the samples.The ozone formation potential(OFP)and sources of VOCs were estimated using the methods of MIR(MaxIncremental Reactivities)and PMF(Probabilistic Matrix Factorization)receptor model,respectively.The results showed that the volume fraction of total VOCs in Suqian ranged from 8.6×10^(-9)to 79.4×10^(-9)during the observation period with the average of 26.9×10^(-9),showing alow level of VOCs in Suqian.The VOCs appeareddistinct zonal differences at the four sites,showing the regional concentrations from high to low as following:ruralindustrial zone(Suqian Technician College:(29.8±18.4)×10^(-9)),the suburban industrial area(Ecological Chemical industrial Park:(28.4±20.6)×10^(-9)),urban residential area(Suqian Middle School:(22.6±11.5)×10^(-9))and urban commercial district(Municipal Power Supply Bureau:(22.3±15.1)×10^(-9)).The daily variations of the four main components(alkanes,alkenes,acetylenes and aromatics)of VOCs at each site were generally consistent.The typical pollutants in Suqian are C_(2)~C_(5) alkanes,ethylene,acetylene,toluene and metaxylene.The key components at different sampling sites were basically the same,indicating the stable sources of VOCs in Suqian.It showed the aromatic hydrocarbons and olefins contributed the most to ozone production from OFP.From the ratio analysis,it showed the VOCs of Suqian had anobvious aging phenomenon during the observation period.Source apportionmentanalysis showed the traffic emission,the using of solventand coatingand industrial processes were the most important sources of VOCs in Suqian.