Chlorinated organic compounds in urban air in Japan.

Air pollution by the principal chlorinated organic compounds chloroform, carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene and tetrachloroethylene was investigated over a period of approximately 1 year at 15 sites in an urban area. Each compound was detected in the range from approximately 0.1 to several ppb; the concentrations of these compounds, with the exception of carbon tetrachloride, were higher than their global pollution levels. The concentrations of 1,1,1-trichloroethane and trichloroethylene especially were very high in the industrial regions, and the concentration of tetrachloroethylene was very high in the industrial and commercial regions. Concentrations were low in spring and summer and high in fall, winter and the rainy season. The correlation between the reciprocal of wind speed and concentrations was found to be subject to seasonal variations. Intake of chlorinated organic compounds by man from the air was estimated from the data to be larger than the allowable intakes determined by WHO and EPA for drinking water.