Atmospheric Distribution of PCDD/F Concentrations in Gyeonggi-do, South Korea

Abstract

Atmospheric concentrations of polychlorinated dibezo-p-dioxins and furans (PCDD/Fs) were investigated at urban-residential (Group Ⅰ: Suwon, Guri and Goyang), industrial (Group Ⅱ: Ansan, Siheung and Bucheon), urbanrural mixed (Group Ⅲ: Yangju, Pocheon and Dongducheon) and rural regions (Group Ⅳ: Yangpyeong) in Gyeonggi-do from February 2012 to November 2012 quarterly. The concentrations of PCDD/Fs ranged from 0.018 to 0.109 pg TEQ m -3 in Group Ⅰ (mean value: 0.061 pg TEQ m -3 ), 0.059 to 0.367 pg TEQ m -3 in Group Ⅱ (mean value: 0.179 pg TEQ m -3 ), 0.072 to 0.836 pg TEQ m -3 in Group Ⅲ (mean value: 0.334 pg TEQ m -3 ) and 0.014 to 0.066 pg TEQ m -3 in Group Ⅳ (mean value: 0.034 pg TEQ m -3 ), respectively. In spite of the less PCDD/F emission sources than Group Ⅱ (industrial regions), the level of PCDD/Fs in urban-rural mixed area showed the highest values with high fluctuation. It's likely that the Group Ⅲ was affected by fugitive emissions such like biomass burning and unregulated open burning. The mean contribution of particle phase to total PCDD/F concentration was above 83% because most of PCDD/F congeners were partitioned into particle phase. We evaluated their gas-to-particles equilibriums with the regression between the particle-gas partition coefficient, K P (m 3 μg -1 ) and corresponding subcooled liquid vapor pressure (P L ). The logarithm-K P of PCDD/Fs was poorly correlated with P L at low ambient temperature (below 10°C) and the slope (m) values for log-log plots of the K P vs. P L was steeper in the Group 2 and Group 3 than residential area. It implies that the slope values were likely influenced by both the direct emission source of PCDD/Fs and ambient temperature.