Measurement of CF sub(2)Cl sub(2) at Memanbetsu over the Period between October 1980 and March 1983

In order to obtain the atmospheric lifetime of CF sub(2)Cl sub(2) ( tau ), the measurements of CF sub(2)Cl sub(2) were performed from October 1980 to March 1983 at Memanbetsu, Hokkaido. The trend of monthly mean volume mixing ratios of CF sub(2)Cl sub(2) when the wind directions were between NW and N was considered to represent the trend of the background mixing ratios. In this case, the mean increase rate from October 1980 to March 1983 was 1 sub(5) ppt/year (ppt=10 super(-12)). From the increase rate obtained in this study and the release rate reported by the Chemical Manufacturers Association (1983), tau was calculated to be 24 (5 similar to infinity ) years. Such a short lifetime seems to be due to the overestimation of the release rate in 1980 and 1981.