抄録
A survey on selected nine volatile organic compounds (VOCs), which are 1,3-butadiene, 1,2-dichloroethane, vinyl chloride, dichloromethane, chloroform, 1,2-dichloroethane, trichloroethylene, 1,2-dichloropropane, and tetrachloroethylene, was conducted in Bangkok in the duration of November 2006 to September 2007. The sampling was made using six-liter Silonite™ canisters on the 24 h basis once a month at 11 sites (5 roadside, 5 residential area, and 1 city background). As the methodology for determination of ambient VOCs, canister-preconcentrator-gas chromatography/mass spectrometry (GC/MS) was used. The method of quantization limits (MQL) of most of the compounds were less than one tenth of their AQS (air quality standard) levels. As the result, their ambient behaviors were characterized from the standpoint of concentration variations at three types of sampling sites as well as in the comparison of their AQS levels. Especially, the concentrations of benzene and 1,3-butadiene at roadside sites were observed to be higher than the ones at residential area and city background sites. These two compounds were supposed to be mainly derived from motor vehicles.
