[Volatile organic compounds concentrations and sources inside new air-conditioned bus].

The distributing profile and concentration level inside new air-conditioned buses with 53 seats have been determined using the method of thermal desorption-capillary GC/MS under vehicle static conditions.Compounds were identified from their mass spectral data by using US National Institute of Standards and Technology(NIST02).The total numbers of identified components were 33 inside buses,including alkenes(15,45.4%),aromatic compounds(9,27.3%),alcohols(4,12.1%),ketones(3,9.1%) and esters(2,6.1%),especially in the range of C_6-C_(10).The top 5 compounds measured inside buses were decane(8.01(mg/m~3)),3-methylhexane(7.10(mg/m~3)),heptane(5.10(mg/m~3)),isoheptane(4.20(mg/m~3)) and 1-Methyl-3-ethylbenzene(3.56(mg/m~3)),and total volatile organic compounds(TVOC)52.5(mg/m~3).The main sources of in-vehicle hydrocarbons and aromatic compounds comes from cabin components and interior trim materials(e.g.,sealants,carpets,adhesives,paints,leather,plastics,PU foam and PE foam) that may retain certain VOCs during manufacturing,and/or emit these compounds over an extended period of time from off-gassing,aging-related breakdown products,heating/cooling and so on.