Characterization of VOCs in hospital waiting areas,Beijing

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.