Atmospheric chlorinated and brominated polycyclic aromatic hydrocarbons (ClPAHs and BrPAHs) in a multi-industrial city of South Korea

Department of Urban and Environmental Engineering (Environmental Science and Engineering)Chlorinated and brominated polycyclic aromatic hydrocarbons (ClPAHs and BrPAHs, respectively) are a PAH derivative group and receive increasing attention due to their high toxicity and occurrence in the environmental media. ClPAHs and BrPAHs are reported to be carcinogenic and several daughter compounds are even more harmful to human health than their corresponding parent PAHs. Understanding the contamination level and fate of these toxic organic pollutants is necessary to control their emission sources into the environment. Nevertheless, studies on the atmospheric pollution of ClPAHs and BrPAHs have been very limited. In particular, there has been no specific research on these PAH derivatives in ambient air of a Korean city. Therefore, this Doctoralal thesis provides detailed knowledge on the characteristics of ClPAHs and BrPAHs in Ulsan, the largest industrial city of South Korea. Published works have mainly investigated the particulate ClPAHs and BrPAHs in several Asian cities. Hence, this thesis studies the physicochemical properties, both gaseous and particulate phases, seasonal patterns, profiles, particle-size distributions, and potential sources of ClPAHs and BrPAHs in Ulsan. The first experimental datasets for octanol-air partitioning coefficients (KOA) and sub-cooled liquid vapor pressures (PL) of ClPAHs and BrPAHs were reported as the temperature dependence. Moreover, the monitoring data in this thesis can cover a relative long-term sampling period and indicate that the seasonal variation of ClPAHs was more apparent than BrPAHs with the winter-high and summer-low pattern. Regarding the phase distribution, ClPAHs and BrPAHs may have a common trend. The gaseous concentrations were recorded as the highest during the warm seasons and the lowest during the cold periods, whereas the particulate concentrations showed a reverse trend. The profiles of ClPAHs and BrPAHs were rather unique between different types of sampling site, possibly illustrating that a combination of various emission sources may be present in Ulsan, e.g., coal combustion, vehicular emissions, and manufacturing operations. The industrial and surrounding areas frequently had higher concentrations of ClPAHs and BrPAHs than the urban and rural sites. ClPAHs and BrPAHs tended to accumulate mostly in the ultrafine particles (with an aerodynamic diameter of less than 1.0 ??m). Furthermore, the particulate ClPAHs and BrPAHs could travel long distances before arriving in Ulsan. The potential source areas were the upwind regions, e.g., North Korea and North and Northeast China. In general, the reported data in this thesis are valuable for not only the environmental scientists, but also the governmental levels to be aware of the pollution state of ClPAHs and BrPAHs in a multi-industrial city of South Korea. The sampling and studied methods used in this thesis may be applicable to monitor the atmospheric concentrations of ClPAHs and BrPAHs in other major cities.clos