廊坊开发区秋季VOCs污染特征及来源解析

Characteristics and source apportionment of ambient volatile organic compounds in autumn in Langfang development zones

使用ZF-PKU-1007大气挥发性有机物(VOCs)在线连续监测系统,于2018年09月25日~10月18日在廊坊市经济技术开发区对99种VOCs进行了在线连续观测.结果显示,观测期间VOCs浓度为69.56×10^-9,烷烃、烯烃、芳香烃、醛酮类及卤代烃体积分数占VOCs比例分别为53.2%、5.9%、7.6%、10.5%和19.3%;使用OH消耗速率LOH和臭氧生成潜势(OFP)估算了观测期间VOCs大气化学反应活性,结果表明醛酮类、芳香烃和烯烃是主要的活性物质;使用气溶胶生成系数法(FAC)估算了VOCs对二次有机气溶胶(SOA)的贡献,得出VOCs对SOA浓度的贡献值为1.13μg/m^3,其中芳香烃对SOA生成贡献占比为94.3%,间/对-二甲苯、甲苯为优势物种;使用PMF模型对VOCs进行了来源解析,识别了5个主要来源,分别为溶剂使用及挥发源(39.6%)、机动车源(22.5%)、固定燃烧源(17.6%)、石化工业源(11.1%)及植物排放源(9.4%),因此,溶剂使用及挥发源、机动车源及燃烧源应为廊坊开发区秋季大气VOCs控制的重点.

A continuous measurement was conducted in Langfang development zones from 25st September to 18st October,2018,and a total of 99VOCs species were detected by ZF-PKU-1007.The resulted showed VOCs average concentration was 69.56×10^-9 during research period,and the average proportions of alkane,alkene,aromatic,aldehydes and ketones,chlorinated hydrocarbon were 53.2%、5.9%、7.6%、10.5%和19.3%;The ozone formation potential(OFP)and the OH radical loss rate(LOH)were applied to assess chemical reactivity of VOCs,result showed aldehydes and ketones,aromatic,and alkene were most active components.Fractional aerosol coefficients(FAC)was used to estimate the potential formation of secondary organic aerosol(SOA),and resulted showed the SOA concentration values was 1.13μg/m^3,aromatic contributed 94.3%to the total SOA formation potential and M-p-xylene and toluene were the dominant species.By applying the positive matrix factorization(PMF)model,five major sources were extracted to identify the sources of VOCs,including solvent usage and evaporation sources(39.6%),vehicle emission sources(22.5%),combustion sources(17.6%),petrochemical industry sources(11.1%)and plant emission sources(9.4%).Hence,solvent usage and evaporation,vehicle emission and combustion emission should be listed as priority of air pollution control strategy for Langfang development zones in autumn.