成都市冬季挥发性有机物污染特征及来源研究

Pollution Characteristics and Source Apportionments of Volatile Organic Compounds of Chengdu in Winter

利用挥发性有机物在线监测仪(GC-FID/MS)在成都市市区开展为期一个月的挥发性有机物监测,分析了VOCs浓度水平、组分构成、日变化规律,并分别利用PMF模型和排放清单法对VOCs的来源进行解析研究。结果表明,监测期间,VOCs小时平均浓度为7610^-9,最高浓度为26210^-9,最低浓度为14.810^-9;监测物种类别中烷烃类占VOCs总体积浓度为38%,炔烃为17%,芳香烃为15%,烯烃为13%,卤代烃为9%,含氧(氮)类化合物为8%,浓度前十的物种分别为乙烷、乙炔、乙烯、丙烷、甲苯、己醛、二氯甲烷、苯、正丁烷和异戊烷,占总浓度的70%以上。烷烃、炔烃、烯烃、芳香烃在8点~10点间均出现浓度峰值,芳香烃、卤代烃以及含氧(氮)化合物浓度最高值出现在凌晨2点~5点;最低浓度则均出现在下午17点左右。基于PMF的方法,VOCs的来源解析结果为工业源贡献32%,机动车贡献26%,生物质燃烧贡献22%,溶剂源贡献7%,油气挥发贡献6%,本底混合源贡献7%;基于排放清单法,2015年成都市VOCs年排放量为36.9万t,工艺过程源、溶剂使用源、移动源分别贡献32%、32%、30%。

99 species of VOCs were monitored for one month by VOCs online monitor in Chengdu City ,in December, 2015. The hourly average concentration of the total VOCs was 76×10^-9 , the highest concentration was 262×10^-9 , while the lowest concentration was 14.8×10^-9 . Alkane, alkyne, aromatic, alkene, and halohydrocarbon accounted for 38%,17%,15%,13%,and 9% of the total VOCs concentration, respectively, while compounds containing oxygen (nitrogen) accounted for 8%. The top ten species were ethane, acetylene, ethylene, propane, toluene, hexanal, methylene chloride, benzene, n-butane and isopentane, contributing more than 70% of the total concentration. Peak concentration of Alkanes, alkene, alkynes and aromatics appeared between 8~10 am, for the other species categories, the highest concentration occurred in the early morning 2~5 am. The lowest concentration for all the VOCs species appeared at 5 pm. The PMF model and emission inventory method was used for source apportionment of VOCs in Chengdu, 6 categories of emission sources were determined. The industry source, vehicle source, biomass burning, solvent using, oil evaporation and the background source contributing 32%, 26%,22%,7%, 6%, and 7% of the VOCs, respectively, however, the result of the emission inventory showed industry source, vehicle source, solvent using contributing 32%, 30%,32% of the total annual emission of organic compounds in Chengdu in 2015, which was 36.9×10 4 tons.