Variations of volatile chlorinated hydrocarbons in ambient air at a suburban area

Variations of Volatile Chlorinated Hydrocarbons in Ambient Air at Industrial Areas in Niigata

“…The mean concentrations of PCM (0.10 -0.11 ppb) in Tsubame and Tokamachi were the same as 0.10 ppb in the Niigata suburban area (Kawata et al 1995) and 0.093 -0.108 ppb at some unpolluted sites in Japan (Makide et al 1979). However, PCM concentration in Kubiki, where PCM has been synthesized, was statistically significantly higher than those in the other two areas, It is comparable to the concentrations in some industrial areas; 0.20 -0.23 ppb in Kawasaki, Japan (Urano et al 1988) 0.24 ppb at Nakago, Niigata (Kawata and Fujieda 1993).…”

“…The gas-chromatographic conditions were as follows: column; glass column (3 m X 3 mm id) packed with 20 % Silicone DC-200 on Chromosorb W AW-DMCS (60/80 mesh), carrier gas; nitrogen of 40 ml/min, temperatures of injector, column and detector; 2OO°C, 90°C and 200°C. The extraction efficiencies for spiked VCHs from the column were 87 -98 %, and the collection efficiencies of the activated carbon column were 91 -100 % as previously reported (Kawata et al 1992(Kawata et al , 1995.…”

“…The mean concentration of PCE in Tsubame, 0.090 ppb was about two times higher than 0.048 ppb both in the Okayama rural area (Oda et al, 1992) and the suburban area in Niigata (Kawata et al 1995) or 0.058 ppb at a rural site in Illinois (Sweet and Vermette 1992). PCE concentration in Kubiki (0.18 ppb) was two times higher than that in Tsubame and a half of 0.36 ppb in Yokohama (Urano et al 1992).…”

“…On the other hand, PCM concentration gives a relatively temperate variation; R values for PCM were only 1.5 -4.3. These characteristic variations of the four VCHs were in the suburban area in Niigata (Kawata et al 1995).…”

“…We have previously reported the concentration levels of the VCHs in ambient air at some areas (Kawata et al 1993(Kawata et al , 1995; the atmospheric VCH concentrations at industrial areas were affected with some factories which used the VCHs, whereas those at a suburban area were lower than those at industrial regions. Furthermore, they were higher in winter season than in summer season, which might be caused by meteorological factors.…”