本文根據中部地區某焚化爐附近7 個觀測點於2001年6月至2002年5 月為止共分為四季，每季一次，所量測到的戴奧辛空氣濃度，估算附近地區的戴奧辛空氣濃度分布，再根據美國環保署在1984 年所提出來的風險係數及致癌風險方程式去計算長期居住於此區的居民可能經由空氣戴奧辛暴露的致癌風險。首先透過敘述性統計量，發現濃度的變化與距離和各季的風向有相關。因而我們可以建立統計模式分別去討論四個季的濃度，接著再透過貝氏方法經由WinBUGS 求得參數的事後分布進而求得未量測點濃度。最後，對於污染源附近區域，發現此區的風險評估超過美國環保署在2000年 所定出來的標準，因此對於長期居住在污染源附近的居民可能有健康上的危害疑慮。但是由於我們對於風險評估的資訊極為有限，加上四季當中有一季的濃度值偏高，因此不能全然接受這個預測結果，有待於進一步的改善。 In this study, analysis were made based on seasonal airborne dioxin concentration measurements at seven sites near an incinerator in central Taiwan obtained during June 2001 to May 2002. The main goal of the study is to estimate the airborne dioxin concentrations in the vicinity of the incinerator, and to calculate cumulative risk assessment of local residents for life-long exposure to incinerator-generated airborne dioxin. Based on descriptive statistics, it was found that the airborne dioxin concentrations were dependent on distance to the incinerator and seasonal wind directions. Using WinBUGS software, the posterior distributions of the Bayesian spatial model parameters were obtained for each season separately. The unknown dioxin concentrations at different sites were then estimated using the predicted model by kriging for each season separately. Average four seasonal dioxin concentrations multiplied by cancer risk factor and life-long exposure divided by body weight and life expectancy was then calculated for spatial risk assessment of local residents. It was found that the risk exceeds the US EPA 2000 safety level. However, due to scarcity of the data and insufficient weather information, large uncertainty is involved to be conclusive.
