個人粉塵採樣器之研發

Abstract

本研究利用多孔材質衝擊板設計並製造一個三階的慣性衝擊器作為個人採樣器，直接測量工作場所的三種粉塵濃度。本採樣器的原理是利用部份自噴嘴噴出之流體透過濾紙會貫入衝擊板內，使得收集效率曲線變得較平板型之衝擊板平緩，在適當的流量及多孔衝擊板阻力係數之設計條件下，可以符合可呼吸性及胸腔區粉塵之採樣效率規範。 首先先利用單孔的慣性衝器作測試，噴嘴直徑為2.6及3.6 mm，並完成流量1.5,2.0 及2.5 LPM，二種聚酯泡綿(100及60 ppi)，四種多孔金屬片(100 , 40, 20, 5 μm)，一種鋁箔當作衝擊板的液體微粒收集效率測試。結果發現，2.0 LPM時使用100 ppi的聚酯泡綿為衝擊板時的收集效率曲線可以和可呼吸性曲線吻合，截取氣動直徑值為3.82 μm，比較可呼吸性曲線之4 μm的誤差只在5%左右。其他的收集板(多孔金屬片和鋁箔)的收集效率曲線過於陟陗，無法與可呼吸性曲線吻合，且截取氣動直徑不符合可呼吸性粉塵的規範。 本研究設計三階粒狀污染物採樣器並完成實驗測驗，結果發現它的胸腔區穿透效率曲線可以符合ACGIH的規範，截取氣動直徑值為9.44 μm，與ACGIH胸腔區曲線之10 μm的誤差只在5.6%左右。同時本採樣器的可呼吸性曲線也符合ACGIH規範，截取氣動直徑值為3.94 μm，與ACGIH可呼吸性曲線之4 μm的誤差只在1.6%左右。

There are three kinds of particulate masses in the workplace defined by the international community: inhalable, thoracic, and respirable particulate mass. Up to now, there are almost no personal samplers for simultaneous sampling of these three particulate mass. This study intends to use the porous impaction substrate to design and manufacture a 3-stage inertial impactor for personal sampling use so that direct measurement of the three particulate mass is possible. This sampler makes use of the fact that part of the fluid flow from the nozzle will penetrate the filter paper and the porous substrate resulting in less sharp collection efficiency than the flat plate substrate. Under the condition of a proper flow rate and resistant factor for the porous substrate, the sampling criteria of the respirable and thoracic particulate mass can be met. The sampler has an inhalable inlet as the first stage with #1 porous substrate (substrate #1). The second stage is an inertial impactor of 10 μm cutoff aerodynamic diameter with #2 porous substrate (substrate #2). The 3rd stage is an inertial impactor of 4 μm cutoff aerodynamic diameter with #3 porous substrate. The after filter is the last stage, which is called #4 substrate. The particulate mass collected on #4 substrate is called respirable mass (RM), while the sum of #4 and #3 particulate mass is called thoracic mass (TM).The sum of all particulate mass collected from #1 to #4 substrates are called inhalable mass (IM). The sampling flow rate of this sampler is designed to be 2-5 LPM. This research intends to design and manufacture this personal sampler. Also the experimental study in the laboratory for the 10 and 4 μm-cut impactors in regards to different porous substrates, different flow rates, different particle diameters will be completed. The best design and flow rate condition for the sampler to meet the international particulate sampling criteria in the workplace will be found. We designed the personal dust samplers and the experimental study had been finished. The results show that when the flow rate is 2.0 LPM, the thoracic penetration curve of the impactor with porous foam (100ppi) is very close to the criteria of ACGIH. The cutoff aerodynamic diameter is 9.44 μm and differs by 5.6 % from 10 μm of the ACGIH thoracic curve. At the same time, the respirable penetration curve is very close to the criteria of ACGIH, too. The cutoff aerodynamic diameter is 3.94 μm and differs by 1.6 % from 4 μm of the ACGIH respirable curve.