玻璃基板粉碎作業的粉塵暴露改善研究

Abstract

TFT玻璃基板主要製程原料為二氧化矽，其成分含量達50至60 %。在國內外研究指出，暴露游離二氧化矽會造成矽肺症、肺炎及加劇致癌力等相關併發症，為保障勞工之健康，勢必要將其暴露濃度控制在容許範圍以下。 一般改善環境粉塵暴露其最有效的方法乃是利用局部排氣系統，在粉塵尚未逸散至人體呼吸帶前予以捕集。但因設置時缺乏標準及專人設計，易使系統控制風速不足，又礙於在既有設備上，工程改善實施難度高、影響生產及高成本等因素，故較難以如願使用系統加以控制。 本研究以某玻璃基板製造業，於玻璃粉碎作業作為粉塵暴露研究對象，瞭解歷年作業環境監測、員工作業型態與控制措施效益，以MOUDI分析粉塵粒徑分布，依其粒徑特性及作業型態樹立改善對策。研究發現作業區域粉塵粒徑主要分布以大顆粒為主；改善措施依粉塵粒大小之運動特性擬定，以DUSTTRAK8530評估其改善成效，改善措施包含改變投料碎玻璃種類(方法一)、禁止使用易造成塵揚之設備(方法二)、汙染源閉密措施(方法三)、汙染源周圍之汙染物清除(方法四)。 研究結果發現，僅啟動局部排氣情況下，粉塵平均濃度為0.034 mg⁄m^3 ，方法一為0.01 mg⁄m^3 ，降低70.6 %；方法二為0.007 mg⁄m^3 ，降低79.4 %；方法三為0.015 mg⁄m^3 ，降低55.9 %；方法四0.019 mg⁄m^3 ，降低44.1 %。 綜合評估效益較佳以及可配合改善方法，依我國作業環境監測建議採樣方法，評估總粉塵濃度改善效益，其汙染源閉密措施(方法三)及汙染源周圍之汙染物清除(方法四)為事業單位可配合改善方法；僅啟動局部排氣情況下，總粉塵濃度為0.58 mg⁄m^3 ，方法三為0.26 mg⁄m^3 ，降低55.2 %；方法四為0.36 mg⁄m^3 ，降低37.9 %，方法三及方法四，皆將濃度降至法規標準0.53 mg⁄m^3 以下。

The main raw material of the TFT glass substrate is silicon dioxide, which accounts for 55±5 % in the compositive contents. A number of studies have found that exposure to silicon dioxide can cause silicosis, pneumonia and increased carcinogenicity and other related complications. To protect the health of workers, it is bound to control its exposure under allowable concentration. Generally speaking, the most effective method to improve the environment of dust exposure is local exhaust, which can trap the dust before it get into human breathing zone. However, due to the lack of standards and professional design, the system usually presents as inadequate wind speed. Furthermore, due to the difficulty of improving existing equipment, the influence on production process, and the high cost of improvement, local exhaust is not the most favoring way to trap the dust. This study takes the glass grinding dust exposure process on in a glass substrate manufacturing as research object, to examine the environmental monitoring work over the years, the staff work patterns and the efficiency of control measures. MOUDI method is adopted to examine dust particle size distribution, and establish improvement measures by particle size and job type states. The result suggests that the most dust particles in working area are large dust size particles, and the improvement measures are decided by according to the motion characteristics of dust particle size of the formulation. Furthermore, DUSTTRAK8530 is adopted to examine the effectiveness of the improvement measures, and the measures include changing the contents of broken glass types, prohibit the use of the equipment could easily lead dust, close pollutant sources, clean pollutant materials around the sources. Finally, we choose the most efficient improvement measure and improve it according to its feasibility, and then assess the effects of improved dust concentration by sampling method suggested in the working environment monitoring method. The result showed that using only local exhaust ventilation(LEV), the average dust concentration in air is 0.034 mg⁄m^3 . However, when we operated LEV with measures above, dust concentration has reduced by 70.6 %(measure 1, value:0.01mg/m3), 79.4 %(measure 2, value:0.007 mg⁄m^3 ), 55.9 %(measure 3, value:0.015 mg⁄m^3 ), 44.1 %(measure 4, value:0.019 mg⁄m^3 ). According to the working environment measurement and NIOSH Manual of Analytical Methods, we comprehensively evaluated the decrease of dust concentration and measures above; the result is that measure 3 and measure 4 were found to be effective and suitable for institutions. When we operated LEV with measure3 and with measure4 the total dust concentration is decreased by 55.2 %(from 0.58 mg⁄m^3 to 0.26 mg⁄m^3 ) and 37.9 %(from 0.58 mg⁄m^3 to 0.36 mg⁄m^3 ).Either measure 3 or measure 4 has the ability to restrict concentration below regulatory limits.