| Abstract: | 在銑床加工過程中，產生的細小灰塵顆粒長時間懸浮在勞工作業現場的空氣中，而這些懸浮微粒會使作業勞工經由呼吸作用從鼻腔進入肺部深層，進而對勞工呼吸道之危害。本研究主要探討特殊鋼銑床作業場所中，在銑床作業區域操作銑床機過程中之勞工作業現場粉塵暴露調查，並提出作業環境之職業衛生改善建議，以提供適當控制措施之建議。
本研究於中部一家特殊鋼銑床作業區利用IOM採樣噐進行個人採樣、Marple 290系列的個人階衝擊式採樣器 (personal cascade impactors)之298型Anderson八階採樣器，進行勞工可吸入性粉塵濃度之分佈及粉塵粒徑分佈並推估出呼吸道不同區位之暴露量，並利用TSI DustTrak 8533氣膠監測儀嘹解粉塵於該空間之濃度分佈變化情形。
IOM採樣結果發現採樣點一的濃度最低為(0.160 mg/m3)，而採樣點二至採樣點六則比較接近分別為(0.649、0.715、0.594、0.693、0.609 mg/m3)，不同天吸入性粉塵濃度變化情形，結果發現第一天、第四天與第五天有相近似之濃度(0.635 mg/m3~0.642 mg/m3)，而第二天與第三天則有相較於其它天有較低之濃度(0.454 mg/m3~0.466 mg/m3)，粉塵粒徑分佈結果，不同天皆呈現一致情形。粉塵粒徑分佈呈單峰分佈以細微粒波峰較為明顯，MMAD為(2.23~2.97μm)，GSD為(2.01~2.26μm)。而粉塵沈積於不同呼吸區域之比例分別為頭區（約佔37%~50%）、氣管區為（約佔13%~17%）及肺泡區（約佔35%~46%）。利用Dusttrak 量測粉塵濃度分佈情形，發現採樣點三及採樣點四位於廠房的底部通風不良易造成粉塵在這附近蓄積而有較高的粉塵濃度。
本研究發現勞工個人呼吸道粉塵暴露濃度，雖均低於勞工作業場所粉塵危害預防標準容許暴露標準之規定，但透過作業現場之觀察，建議所有銑床機更新為封閉式銑床機或廠房增設通風排氣裝置以降低空氣中粉塵微粒暴露。但依不同呼吸區的結果，不同採樣點所沉積的暴露部位不同，因此仍須提供不同防護需求之呼吸防護具，且須注意應配戴的密合性及正確的配帶方法。本次研究亦發現，粉塵微粒因廠房通風不良有蓄積之情形產生，建議宜加強改善廠房內作業環境的通風換氣。
In the milling machine processing, the fine dust particles suspended in the air for a long time, and these suspended particles will enter to the lung of workers through the nose by respiration, causing hazard for worker respiratory system. This study mainly discussed the investigation of dust exposure during used the milling machine in working area, proposed recommendations for occupational health improvement in the work environment to provide advices for control.
This study used the IOM sampler for personal sampling, used personal cascade impactors (marple 290) and size-selective samples (Anderson 298) for worker inhalation dust concentration and the dust size distribution in a steel milling machine operation area which is in the middle of Taiwan to estimate the exposure of different respiratory zone, using the particle detector (TSI DustTrak 8533) to find out the concentration distribution of dust in the space.
The IOM sampling results found that the lowest concentration of the sampling points 1 was 0.160 mg/m3and the sampling points 2 to 6 were close. (0.649, 0.715, 0.594, 0.693, 0.609 mg/m3 respectively). According to the inhalation dust concentration change of different days, we found that there was a similar concentration (0.635 mg/m3 to 0.642 mg/m3) of the first day, the fourth day and the fifth day, and there was lower concentration (0.454 mg/m3 to 0.466 mg/m3) of the second and third days. The results of particle size distribution showed consistent conditions on different days.
The particle size distribution of dust had a single peak distribution with fine particles, MMAD (2.23 to 2.97 μm) and GSD (2.01 to 2.26 μm). The proportion of dust deposited in different breathing areas was the head area (about 37% to 50%), the trachea area (about 13% to 17%) and the alveolar area (about 35% to 46%). Using particle detector to measure the distribution of dust concentration, it was found that sampling points 3 and 4 were locate at the bottom of the factory building and poor ventilation caused dust accumulation which had a higher dust concentration.
This study found that the dust exposure concentrations of personal respiratory of workers were lower than the standard of dust hazard prevention standards, through the observation of the working environment, this study recommended that all milling machines should be updated to “enclosed” milling machines or increase the ventilation and exhaust devices to reduce air dust particulate exposure. Depending on the results of different breathing areas, the different exposure area deposited at different sampling area, so it was still necessary to provide respiratory protective equipment with different protection needs, and to pay attention to the tightness and using the correct method. This study also found that dust particles were generated due to poor ventilation of the factor building. We suggested that improve the ventilation of working environment. |
