Abstract
The measurements of five chlorocarbons (CC), chloroform (CF), carbon tetrachloride (CT), 1, 1, 1-trichloroethane (1, 1, 1-T), trichloroethylene (TR) and tetrachloroethylene (TT) in atmospheric environment have been carriede out at the five sites of Osaka City between September in 1989 and November in 1992 (seven seasons). The results may suggest as follows: (1) only small differences were observed among the average concentrations of these CC at the five sites in the narrow area such as Osaka City, (2) the relatively large changes were detected in the seasonal average concentrations of three CC except CF and CT, (3) the emission sources of these CC may be classified roughly into two categories of wastewater (water area) and other vaporation sources. The average ratio (21.5) of [1, 1, 1-T+TR+TT] / [CF] in the ambient air was much higher than that (6.72) published in the wastewater. On the assumption that all of ambient CF is caused by wastewater, the contribution of this source could be calculated to be 31.3 % from the both ratios, which may be the maximium contribution to the ambient 1, 1, 1-T, TR and TT.
