Abstract
Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in ambient air were analyzed for one year from Sep. 1996 to Aug. 1997 in Matsuyama. Average concentration of PCDD/Fs and TEQ were 13.4 pg/m3 and 0.18 pg-TEQ/m3, respectively. Daily intake of PCDD/Fs by human through the air was estimated to be 2.7 pg-TEQ/ day.
Seasonal change of monthly averaged PCDD/Fs concentration was observed during the sampling period. The concentration was lower in Summer and higher in the rest of the season. Among meteorological factors, including temperature, air pressure and precipitation, only wind speed showed a clear correlation (negative) with the concentration. Relative concentrations of lower chlorinated congeners tended to increase during Summer, probably because of the decrease of dry/wet deposition in Summer due to their higher gas phase proportion in hot Summer season.
