北京市医院候诊区空气中VOCs的污染特征

Characterization of VOCs in hospital waiting areas,Beijing

对北京市3家医院9个候诊区室内空气进行采样,样品采用预浓缩仪与GC-MS联用系统进行定量分析,共检测出65种挥发性有机物(VOCs).医院室内外VOCs的平均浓度为123.64～713.22μg/m3,其中烷烃、烯烃、芳香烃约占61%～98%.烷烃以乙烷、丙烷、正丁烷、异丁烷、异戊烷为主,占50%以上.烯烃的主要成份为乙烯、丙烯、异戊二烯,约占总烯烃的53%～83%.芳香烃以苯、甲苯、乙苯、二甲苯、苯乙烯为主,约占79%～98%.不同的候诊区芳香烃的组成差异大,病理科候诊区F的芳香烃主要来自二甲苯的贡献(58%±24%),而挂号处G和口腔科候诊区H的甲苯所占芳香烃的比例最大(34%±26%).绝大多数采样点的室内和室外VOCs浓度的比值(I/O)大于1.0,一些候诊区中芳香烃、卤代烃和环烷烃的I/O远大于1.0,表明这些污染物存在一定的室内来源.

Indoor and outdoor air samples were collected from 9 waiting areas of 3 hospitals in Beijing.Sixty-five kinds of VOCs were identified and quantified by the preconcentrator-GC/MS system.The mean concentration of VOCs ranged from 123.64 to 713.22μg/m3.The major components were alkanes,alkenes and aromatics,and they accounted for 61%~98% of the total content.Ethane,propane,n-butane,i-butane and isopentane were the main alkanes（above 50%）.The dominating components of alkenes included ethene,propene,isoprene（about 53%~83%）.79%~98% aromatics were made up of benzene,toluene,ethylbenzene,xylenes and styrene.The distribution characteristics of aromatics among waiting areas was quite different.Xylenes（58%±24%） were the most important contributor for F waiting area,while toluene was very high in G and H waiting areas.The indoor/outdoor（I/O） ratios of VOCs concentration were above 1.0 in most sampling sites.I/O ratios of aromatics,halohydrocarbons and cyclanes were much higher than 1.0 in some sampling sites,indicating prominent indoor sources.