多氯萘於環境無所不在，且因其對環境及人體之危害，斯德哥爾摩公約已將其列為新興持久性有機污染物，因此，多氯萘之環境問題目前備受關注，本研究將調查周界及固定污染源煙道氣排放之多氯萘特性，結果顯示周界多氯萘濃度於工業區高於都市區及鄉村區，此外，夏季濃度高於冬季，而根據多氯萘物種分布指出工業區之多氯萘物種與都會區及鄉村區有顯著性差異，故可推測工業區之多氯萘來源與都會區及鄉村區相異。而根據固定污染源之多氯萘調查結果顯示二次銅冶煉廠排放之多氯萘濃度高於廢棄物焚化爐，且類戴奧辛之多氯萘對煙道氣及飛灰毒性當量濃度分別貢獻1-3%及0.3%，而針對空氣污染防制設備去除多氯萘之結果顯示，活性炭噴注+袋式集塵器及選擇性觸媒還原對煙道氣中多氯萘之去除效率分別可達94.3%及98%。儘管活性碳注入+袋式集塵器及選擇性觸媒還原去除多氯萘之機制不同，兩空氣污染防制設備對多氯萘去除效率皆隨氯數上升而增加，此可推測選擇性還原觸媒對多氯萘之去除機制為脫氯反應且低氯數之多氯萘亦有生成潛勢。本研究了解多氯萘之特性含(1)周界及固定污染源之多氯萘濃度(2)不同空氣污染防制設備對多氯萘之去除效率及排放因子，為典型排放源提供適合之操作參數有效處理煙道氣之多氯萘。;Polychlorinated naphthalenes (PCNs) are ubiquitous in environment and have been receiving much public concern due to the adverse effects on human health and environment. However, study on PCNs has never been conducted in Taiwan in which high potential impacts of these compounds are anticipated. As the first study on PCNs in Taiwan, this study aims to characterize the occurrences of PCNs in ambient air collected from three different sites in northern Taiwan and emissions of PCNs from typical sources including two municipal waste incinerators (MWIs) and two secondary copper smelting (SCS) plants. Results indicate that higher level of PCNs is found at industrial (ID) site compared with those collected from urban (UB) and rural (RR) sites. Concentrations of ambient PCNs are higher in summer compared with those measured in winter for all three sampling sites. Homologue distribution of PCNs measured at ID site is different from two other sites for both gas and particulate phases, suggesting that different sources contribute to PCNs collected at ID site and other sites. Results of the logKp-logPL relationship indicate that both adsorption and absorption govern gas/particle partitioning of atmospheric PCNs. Emission factors of PCNs from SCSs are higher than those observed for MWIs. Minor contributions of dioxin-like PCNs to total TEQ concentration are found for flue gas (1-3%) and fly ash (0.3%). Performances of different air pollution control devices (APCDs) reveal that ACI+BH and SCR are effective for removal of PCNs from flue gas with the removal efficiencies ranging from 94.3 to 98%. Removal efficiency of PCNs achieved with ACI+BH and SCR increases as the chlorination level increases although different mechanisms govern the removal of PCNs in SCR and SDA+ACI+BH. The results suggest that dechlorination in SCR or reformation of low chlorinated homologues might occur within or after SCR, respectively. Increments of PCN concentration and chlorination level of PCNs in flue gas passing through ESP indicate that PCNs are formed in ESP via chlorination mechanism. Significant decrease of temperature in SDA plays an important role in PCN removal due to the transfer of PCNs from gas phase to particulate phase. The diagnostic ratios are firstly proposed and employed in this study for identifying potential sources of PCNs in ambient air. Thermal processes are identified as major sources of PCNs at ID site. PCNs collected at UB and RR sites are mixed sources of thermal emissions and evaporation, however, more influence of thermal sources in winter and more impact of evaporation sources in summer are observed. PCA results indicate that PCNs in some ambient air samples collected are originated from MWIs and SCSs investigated, while PCNs in other samples are emitted from other thermal sources and evaporation from technical mixtures. The results obtained in this study are important for understanding the characteristics of PCNs including (1) level, potential sources and gas/particle partitioning of PCNs in ambient air; (2) emission factors, performances of different APCDs and appropriate operating parameters for effective removal of PCNs in typical sources.
