Abstract
In this report, the monitoring results of dichlorodifluoromethane (CFC12), trichlorofluoromethane (CFC11), 1, 1, 2-trichloro-1, 2, 2-trifluoroethane (CFC113), 1, 1, 1-trichloroethane, cabon tetrachloride, trichloroethylene, tetrachloroethylene, chloroform and dichloromethane in urban atmosphere of coastal industrial area in Kanagawa prefecture were presented. Monitoring term was from Jan. 1990 to Jan. 1997. These chemical substances were measured by using adsorbent collection/solvent extraction/GC-ECD.
During the significant reduction of specific CFCs (CFC12, CFC11, CFC113), atmospheric concentrations of CFCs, 1, 1, 1-trichloroethane and carbon tetrachloride had been decreasing: in 1991, concentrations of CFC12, CFC11, CFC113, 1, 1, 1-trichloroethane, carbon tetrachloride, trichloroethylene, tetrachloroethylene and chloroform were 0.87 ppbv, 0.45 ppbv, 0.53 ppbv, 2.8 ppbv, 0.15 ppbv, 0.46 ppbv, 0.33 ppbv and 0.10 ppbv, respectively, and in 1996, after the total elimination, these were 0.62 ppbv, 0.34 ppbv, 0.16 ppbv, 0.41 ppbv, 0.10 ppbv, 0.65 ppbv, 0.29 ppbv and 0.07 ppbv, respectively. Dichloromethane had been measured from Aug. 1994 and its concentration was 1.9 ppbv in 1996. After reduction of CFCs started, atmospheric concentration of trichloroethylene had been increased.
Formerly, trichloroethylene was replaced by 1, 1, 1-trichloroethane and CFC113 because of their low toxicity, however, specific CFCs were phased out and trichloroethylene became the substitute chemical.
