宜宾市冬季挥发性有机物污染特征及来源

为了解宜宾市冬季VOCs（volatile organic compounds，挥发性有机物）污染特征，于2016年12月选取宜宾市2个国控环境监测点位，采集冬季环境空气VOCs样品，利用三级冷阱预浓缩仪-气相色谱质谱联用仪（GC-MS）测定大气中89种VOCs物种，分析VOCs体积分数及其物种组成情况，并对其主要来源进行识别.结果表明:宜宾市区冬季环境空气中φ（VOCs）平均值为35.10×10-9，φ（VOCs）最高值和最低值分别为67.34×10-9、20.58×10-9；监测VOCs物种类别中芳香烃占比最高，其次为烷烃、卤代烃；体积分数较大的VOCs物种主要为苯、甲苯、氯甲烷、二氯甲烷、异丁烷、异丙醇、正丁烷等.CMB（化学质量平衡）模型源解析宜宾市冬季环境空气VOCs的六大主要贡献源分别为移动源、油气挥发源、溶剂使用源、工艺过程源、生物质燃烧源和其他源.以2015年为基准年，利用排放因子法对宜宾市VOCs进行排放量计算发现，宜宾市VOCs年排放量为39.54×103 t，其中，工艺过程源、溶剂使用源、移动源、化石燃料燃烧源的贡献率分别为35.5%、24.5%、28.9%、8.0%.研究显示，对宜宾市冬季环境空气中VOCs贡献率较大的污染源分别为移动源、溶剂使用源、工艺过程源等。 

Pollution Characteristics and Source Apportionments of Volatile Organic Compounds in Yibin City in Winter

In order to understand the characteristics of volatile organic compounds in Yibin City in winter, air samples were collected at two sites in December 2016. Eighty-nine species of volatile organic compounds (VOCs) were measured by using pre-concentration-GC-MS method. This study investigated the volume fraction of VOCs and its ingredients. In addition, the main sources of VOCs were also identified. The results showed that the average volume fraction of VOCs was 35.10×10^-9, and the highest volume fraction was 67.34×10^-9 while the lowest volume fraction was 20.58×10^-9. Aromatic hydrocarbons were the highest proportion in the monitored species category, followed by alkanes and halogenated hydrocarbons. Species with a large volume fraction were benzene, toluene, methyl chloride, dichloromethane, isobutene, isopropanol, n-butane and so on. Source apportionment for VOCs in Yibin City was taken by CMB model and emission inventory method. The CMB results indicated 6 major contribution sources of VOCs were vehicle source, hydrocarbon volatile source, solvent source, industry source, biomass burning. The results obtained from the emission inventory in 2015 were the industry source, solvent source, vehicle source, fixed burning that contribute 35.5%, 24.5%, 28.9%, 8.0%, respectively. Overall, the main sources of VOCs in the winter ambient air in Yibin City are vehicle, solvent and industry.