以氣膠吸入效率預測模式評估勞工總氣膠與可吸入性氣膠暴露之可行性研究

Application of Aerosol Aspiration Efficiency Predictive Model for Predicting Inhalable and Total Aerosol Exposures of Nickel Industry Workers

本研究係利用個人可吸入性氣膠分徑器（PIDS，personal inhalable dust spectrometer）於10個鎳工業作業場所實施採樣，並結合環境風速測定資料， 利用氣膠採樣器吸入效率預測模式，以理論預測各作業場所勞工之總氣膠，與 可吸入性氣膠暴露量之比較值（Sp）。研究同時並針對前述作業場所，另各以5至15名勞工同時攜帶總氣膠採樣器（37-mm個人採樣器）及可吸入性氣膠採樣器（IOM個人採樣器）進行採樣，以求取各作業場所勞工之總氣膠與可吸入性氣膠暴露之實際比較值（Sm）。研究結果發現，各作業場所中勞工之總氣膠與可吸入性氣膠之模式理論預測比較值，均遠低於實際量測所獲之比較值，究其原因可能因（1）勞工於作業時非與環境風向呈方向角度平均（orientation-averaged）； （2）作業場所內各點之氣膠粒徑組成與環境風速並非均勻分布；及（3）吸入效率預測模式無法解釋低風速時重力對吸人效率之影響。另本研究亦發現，欲轉換以往各鎳工業場所作業勞工之總氣膠暴露資料為可吸入性氣膠暴露資料時，其轉換因子之求取應以個人採樣法直接推估為最佳，唯如受限於採樣之人力、設備與經費，欲以吸入效率預測模式推估時，此時模式推估值需以迴歸式Sm= 1.82Sp-1.48修正之，其R2為0.72。

This study is set out to test the efficacy of the proposed method of directly applying the workplace data, obtained from both the particle size distribution samplings and wind velocity measurements, to a recently developed aspiration efficiency predictive model to obtain the theoretical ratio (Sp) of the amount of inhalable aerosol exposure to the total aerosol exposures of workers at 10 nickel industry workplaces. In addition to theoretical ratio prediction, personal samplings are also conducted at each of the 10 workplaces. About 5 to 15 workers were chosen for personal sampling at each workplace. During field sampling, each worker was assigned to wear one total aerosol and one inhalable aerosol samplers side by side to obtain the practical ratio ( Sm ) between the amount of inhalable aerosol exposure to the total aerosol exposures of workers at each workplace. Obtained results show that Sp values are significantly different from Sm for all tested workplace data, which might be due to (1) the orientation of each selected worker could not be simply described as an orientation-averaged situation, (2) the particle size distribution within any given workplace might be different from one location to another, and (3) the inadequacy of the selected model on predicting aspiration efficiency of samplers used in workplaces with low wind speed situations. Due to the fact that personal sampling method requires more manpower and cost more than the proposed method, the study results show that the proposed method is feasible for nickel industry workplaces on the condition that the obtained Sp could be further converted into Sm by using the empirical equation of Sm = 1.82Sp-148 (R2=0.72).