Size distribution and the concentrations of heavy metals in welding particles

• Main Authors: Chang Shang-Lang, 張勝琅
• Other Authors: Chen Hsiu-Ling
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/93510173409086739227

碩士 === 弘光科技大學 === 職業安全與防災研究所 === 101 === In this study, the industry manufacturing fitness equipments in Chang-hua county was selected for measuring the exposure hazards of welding fume. IOM and Marple for inhalable and particle size distribution sampling were processed respectively. Meanwhile, an exposure chamber experiment to explore the removal efficiency for welding fume by using alternative masks to remove inhalable dust and heavy metals, which were analyzed by ICP-OES. The results showed that the concentrations of inhalable welding fume were in powder coating area (15.58mg/m3)> automatic welding area (0.66 mg/m3)> manual welding area (0.53mg/m3)> punch area (0.18 mg/m3)> Cutting area (0.16 mg/m3). The mass level of powder coating area is higher than the occupational exposure limit (5mg/m3) set by ACGIH, NIOSH and permissible exposure level (PEL) of Taiwan workplace standard. The mass median aerodynamic diameter (MMAD) of coarse particles ranged from 9.65μm~9.93μm, fine particles: 0.66μm~1.2μm, which showed bimodal distribution in manufacturing fitness equipments. The welding operation area in fine aerodynamic mass median diameter is less than other areas without welding works. Aluminum is one of major heavy metal in power coating area inside the fitness equipments industry; iron is in welding operation area; iron and aluminum in punch and in cutting area. In the exposure chamber experiments, chromium, nickel are the major sampling inside exposure chamber while using stainless steel electrode. The removal efficiency test for welding fume by using the different masks barrier, the removal efficiency was as the following: N95 (64.42%)> R95 (52.42%)> FFP1 (48.75%)> activated carbon (45.0%)> cotton (37.5%), and N95 masks barrier was the excellent one. While the assessments were classed as coarse particles (PM21 ~ PM10) and fine particles (PM10 ~ PM1), the removal efficiency of FFP1 masks were 76.3% and 91.1%, respectively. In the fine particles (<PM1), N95 masks showed the best removal for 85.1%. Over 70% of the fumes in the exposure chamber experiments with the particulate diameter was 1μm or less, therefore, using of N95 masks was recommend to remove this kind of welding fumes. Key word：welding fumes, heavy metals, particle size distribution, removal efficiency