| 摘要: | 國際癌症協會宣告PM2.5 (指氣動直徑小於或等於2.5 μm懸浮微粒)及微粒重金屬Cr、As、Ni、Cd和Pb對人體具有致癌風險。本文引用2017年至2019年在環保署花蓮、板橋、忠明、斗六、嘉義和小港測站採樣的PM2.5數據，探討金屬元素與PM2.5質量濃度相關程度、時間變化趨勢，及健康風險的時空變化，然後使用條件雙變量機率函數(Conditional Bivariate Probability Function, CBPF)評估金屬元素健康風險發生機率值較高的區位。
結果顯示金屬元素是來自於PM2.5，但各測站金屬元素濃度相當微量，在PM2.5質量濃度占比3~4%，兩者線性相關係數數值介於0.5至0.6間。六個測站以Al、Fe、Na、Mg、K和Ca六個金屬元素有較高濃度，愈往南部的測站金屬元素濃度愈高。非致癌風險金屬元素的危害商數(Hazard Quotient, HQ)由高至低為Mn> V> Co> Ba> Se，有少數測站及樣本Mn的HQ> 1，各測站四季危害指標(Hazard Index, HI)則都在美國環保署提供的安全範圍內(< 1)。致癌金屬的致癌風險(Carcinogenic Risk, CR)由高至低為Cr (VI)> As> Ni> Cd> Pb，Cr (Ⅵ)的CR在各測站普遍超出閾值(1.00×10-6)，雖然總致癌風險(Total Carcinogenic Risk, TCR)仍在美國環保署提供的可容忍範圍內(< 1.00×10-4)。
各測站以CBPF結合污染源區位，花蓮、忠明、斗六、嘉義、小港測站在東北東至西北方向，板橋測站在西南西方向，有超過金屬元素健康風險閾值機率較高的區位，普遍是受到移動和固定污染源影響。小港測站HI和TCR超過健康風險閾值區位的機率數值在各測站最高，花蓮測站則低很多。;The International Agency for Research on Cancer (IARC) declared that PM2.5 (referring to fine particulate matter with an aerodynamic diameter equal to or less than 2.5 μm) and heavy metals Cr, As, Ni, Cd, and Pb pose carcinogenic risks to human health. This study used PM2.5 sampling data from six monitoring stations named Hualien, Banqiao, Zhongming, Douliu, Chiayi, and Xiaogang, collected between 2017 and 2019 by the Environmental Protection Administration. The study aims to explore the correlation between metal elements and PM2.5 mass concentrations, their temporal variations, and the spatiotemporal variations of these metal elements in health risks. The Conditional Bivariate Probability Function (CBPF) is further employed to assess locations with higher occurring probabilities of health risks associated with metal elements.
The results show that metal elements originate from PM2.5, but their concentrations at each station are relatively low, accounting for approximately 3-4% of the PM2.5 mass concentration. The linear correlation coefficient between metal elements and PM2.5 falls between 0.5 and 0.6. Among the six stations, Al, Fe, Na, Mg, K, and Ca exhibit higher metal element concentrations, with levels increasing when moving southwards. The non-carcinogenic metal elements are ranked in order of Hazard Quotient (HQ) from high to low: Mn > V > Co > Ba > Se. A few stations and sampling days have HQ values for Mn exceeding 1, while the Hazard Index (HI) for all stations throughout the seasons remains within the safe range (<1) set by the US Environmental Protection Agency (US EPA). Regarding carcinogenic metal elements, the Carcinogenic Risk (CR) ranks from high to low: Cr (VI) > As > Ni > Cd > Pb. The CR for Cr (VI) generally surpasses the threshold (1.00×10-6) at all stations. However, the Total Carcinogenic Risk (TCR) remains within the acceptable range provided by the US EPA (<1.00×10-4).
By combining the CBPF with pollution source locations, the probability of higher health risks associated with metal elements is identified in the northeast-east to northwest direction for Hualien, Zhongming, Douliu, Chiayi, and Xiaogang stations, and in the southwest-west direction for Banqiao station. These locations are commonly affected by mobile and stationary pollution sources. The probability values of exceeding health risk thresholds for both HI and TCR are highest at the Xiaogang station, while Hualien station shows much lower probabilities. |
