飛機維修作業勞工之有機溶劑暴露評估研究

Abstract

飛機維修作業使用種類繁多之有機溶劑，其中尤以飛機除漆、噴漆及零組件清洗作業使用的溶劑量最多。本研究之目的為評估該作業勞工之有機溶劑暴露情形，並探討造成暴露濃度差異之可能因素，以作為飛機維修棚廠設施規劃及推動安全衛生改善措施之參考。 本研究選定國內三個飛機維修廠不同機型飛機之除漆、噴漆及零組件清洗作業，並依據勞委會及NIOSH公告方法進行作業環境之定點及個人採樣分析。有關除漆及零組件清洗作業之採樣是以直讀式儀器先行偵測空氣中有機溶劑之濃度範圍，再以活性碳管針對不同機型飛機或不同工作位置分別進行定點及個人採樣；噴漆作業則是針對不同機型飛機於底漆及面漆噴塗時分別進行定點及個人採樣。所有採集之樣品均是利用氣相層析儀/火焰離子偵測器進行分析。 在飛機除漆作業之採樣分析結果顯示，地面上之作業勞工其二氯甲烷個人暴露濃度( 42.01□31.86 ppm)遠高於距地面約四米高度之工作平台上作業勞工的暴露濃度(20.41□11.43 ppm)。且二氯甲烷暴露濃度隨著工作時程之進展而有逐漸下降之趨勢(在一架空中巴士A300飛機除漆作業，其第一工作日之平均暴露濃度為55.69 ppm，二十四小時後已下降為14.82 ppm)。在飛機噴漆作業之採樣分析結果顯示，噴塗底漆時，以甲戊酮(5.55□4.96 ppm)及甲苯(10.72□8.28 ppm)之濃度高於1/10 PELs。而噴塗面漆時，則以甲基異丁酮(7.10□5.80 ppm)、甲戊酮(14.34□8.52 ppm)及環已酮(3.26□2.66 ppm)之濃度高於1/10 PELs。零組件清洗作業則以甲苯(44.11□16.34 ppm)進行擦拭工作時之暴露濃度接近1/2 PELs較高，惟所有噴漆作業及零組件清洗作業勞工之有機溶劑暴露濃度均合於法規恕限值以下。 綜合研究結論顯示，在各型飛機之除漆作業初期，作業環境中二氯甲烷濃度高於我國法令規定之容許暴露濃度，需進行改善。飛機噴漆作業，雖然氣態的有機溶劑之濃度不高，但粒狀污染物中的有機物則值得進一步進行探討。而零組件清洗作業，應對擦拭工作區進行改善，以降低甲苯之暴露危害。

There have many solvents used in aircraft maintenance, especial in paint stripping and paint spraying and components cleaning operations. The main objective of this study was to investigate the organic solvent exposure of aircraft maintenance workers. The results of the personal exposure survey and environment measurement could be use as the reference for chemical hazard control and workplace environment improvement for aircraft maintenance facilities. Three plane hangars for aircraft paint stripping/spraying and components cleaning workshops in Taiwan were selected, and the Council of Labor Affairs and NIOSH recommended sampling/analytical methods were used in this study. We used a direct reading instrument for the preliminary survey of the methylene chloride exposure concentrations in the depainted and cleaning operation area. Then, activated charcoal tubes were used to investigate the personal and area exposure concentration of the organic solvents in the paint stripping, components cleaning and primer /topcoating spraying operations. All samples were collected during painting and stripping operations in different aircraft models and different sites, and were analyzed by chromatograph with flame ionization detector (GC/FID). During aircraft paint stripping, the experimental results reveal that methylene chloride personal exposure concentration (42.01±31.86 ppm) at the ground area was higher than that (20.41±11.43 ppm) at the working platform about 4 meters high above the ground. The exposure concentration was decreased from 55.69 ppm to 14.82 ppm (after 24hrs) in Airbus A300 paint stripping. During paint spraying, methyl n-amyl ketone (5.55□4.96 ppm) and toluene (10.72□8.28 ppm) in primer spraying were above 1/10 the Permissible Exposure Limits (PELs). Methyl isobutyl ketone (7.10□5.80 ppm), methyl n-amyl ketone (14.34□8.52 ppm) and cyclohexanone (3.26□2.66 ppm) in topcoating spraying were also above the 1/10 PELs. During components cleaning, air concentration of toluene was higher than other solvents, and its concentration (44.11 □16.34 ppm) was near the 1/2 PELs in wiping parts area. All concentrations of organic vapor were below PELs in primer/topcoating spraying and component cleaning operations. In summary, we have found that: (1) Exposure concentration of methylene chloride in the initial paint stripping operation stage of every aircraft model was over the PELs (50 ppm) set by the Council of Labor Affairs. Corrective actions are needed. (2) All solvents exposure concentrations were below the PELs during paint spraying operation, however, the organic compounds in particle pollutants deserve further investigation. (3) Wiping parts area of component cleaning workshop should improvement to reduce the hazard of toluene exposure.