대기 중 분진입경별 다이옥신류의 분포특성에 관한 연구

Abstract

This study was carried out to investigate the behavior of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans by particle size in atmosphere. The samples were collected using a high-volume cascade impactors at pukyong national university(PKNU) in Busan from January to October 2008. The distribution of particle concentration and concentration of PCDD/DFs with respect to particle size were presented by using various methods. More than 60% of particles were in <2.1㎛ size classes and the particles showed the bimodal size-distribution pattern characteristic of urban particles. The largest amounts of particle-bound PCDD/DFs were found on small particles with aerodynamic diameters(d_(ae)) of less than 0.69㎛. More than 89% of the total PCDD/DFs and 87% of the total TEQs loading were detected in particles of d_(ae)<2.1㎛. The concentration of PCDD/DFs increased with decreasing particle size. Different homologue patterns were observed in the particle/gas phase. High chlorinated PCDD/DFs dominated the particle phase while low chlorinated PCDD/DFs dominated the gas phase. This is due to persistence and existence based on their physicochemical properties, such as vapor pressure and boiling point. An adsorptive partitioning model developed by Junge-Pankow is often used to calculate the theoretical partitioning of semi-volatile organic compounds. The fitting curve line plotted log partition coefficient(K_(p)) versus log sub-cooled liquid vapor pressure(P^(0)_(L)) showed difference, depending on the season. K_(oa)-based absorption model was used to predict the partitioning of PCDD/DFs to atmospheric particulate matter and to estimate gas-phase concentrations. According to season, the fraction of organic matter in aerosol was different. Especially, the value in winter was higher than other seasons. Temperature is one of the most important factor governing the partition of particle/gas phase of PCDD/DFs in the atmosphere from a result in this study.