VOLATILE HYDROCARBONS (C-6-C-10) MEASUREMENTS AT REMOTE SITES OF TAIWAN DURING THE PEM WEST-A EXPERIMENT (1991)

For the first time, ambient volatile hydrocarbons in the range of C-6- C-10 were measured at four remote sites of Taiwan in the period of Jun e 1991 to October 1992, and the data collected in Kenting was a part o f the Pacific Exploratory Mission-West A experiment sponsored by Natio nal Aeronautics and Space Administration (NASA). All the concentration of target hydrocarbons except toluene lower to sub-ppb range were obs erved at four sampling sites. Toluene was shown the higher standard de viation means the more significant the diurnal variation during sampli ng period in Lanyu. The very simple hydrocarbons patterns at each site presented the lack of direct anthropogenic pollution source in the re mote regions. The most prevalent component was generally toluene follo wed by the xylene isomers and benzene. Results obtained from Kenting i ndicated at least three different mass types were observed at the site . The average concentrations (ppbv) determined for benzene and toluene in the continental outflow were 0.25+/-0.05 and 0.13+/-0.05, respecti vely. In the marine boundary layer were 0.15+/-0.06 (benzene) and 0.18 +/-0.11 (toluene) and 0.66+/-0.11 (benzene) and 1.08+/-0.42 (toluene) in the urban plume. The data collected indicated that the East Asia re gional sources of pollution enhanced the average trace gas concentrati ons in the background atmosphere. (C) 1998 Elsevier Science Ltd.