多孔衝擊器負載效能評估

本研究主要將一般傳統之平面、或多孔材質衝擊板面改良成下凹狀態，並嘗試以生物培養基常用之胰蛋白大豆瓊脂(Trypticase Soy Agar, TSA)披覆、充填於多孔衝擊器(multi-hole impactor)衝擊板上，以減少衝擊器對固態氣膠採樣時之彈跳負載現象。實驗主要產生酒石酸鉀鈉(potassium sodium tartrate tetrahydrate, PST)、甲基丙烯酸甲酯(polymethyl methacrylate, PMMA)為挑戰氣膠，另外，為了模擬環境中較為惡劣的氣膠濃度狀況，產生重量濃度約為7.22 mg/立方公尺之酒石酸鉀鈉氣膠，以供進行氣膠負載實驗。氣膠粒徑偵測方面主要以氣動粒徑微粒偵測器(aerodynamic particle Sizer, APS)進行氣膠上、下游濃度及貫穿率之測試，並以Am-241中和挑戰氣膠電荷至波茲曼分佈。研究並比較矽油(Silicone Oil)、及TSA之披膜(coating)效果。結果發現TSA之披膜效果，遠比矽油有較佳之防止固態酒石酸鉀鈉氣膠彈跳之效果，但在2小時之連續氣膠負載採樣後，卻發現TSA有縮小乾燥之現象，因而氣膠彈跳現象又重新發生。研究另以矽油塗抹於TSA表面，使形成矽油-TSA雙層披膜狀態，可解決長時間採樣及固態氣膠負載狀況。然而在使用非水溶性之PMMA標準粉塵搭配多孔衝擊器進行實驗時，發現矽油--TSA雙層披膜法並無法抑制非水溶性之PMMA彈跳現象，是以矽油--TSA雙層披膜法，對水溶性固態PST有較佳之收集、抑制彈跳效果。

關鍵字

瓊脂；彈跳；披膜；矽油

並列摘要

Particle bounce and the loading effect were reduced by recessing the impaction plate to form a cavity that was filled with Trypticase Soy Agar (TSA). An ultrasonic atomizing nozzle was used to generate challenge aerosols (potassium sodium tartrate tetrahydrate, PST). The mass concentration of the challenge aerosol was 7.22 mg/m^3, a worst case scenario. A 10-mCi radioactive source, Am241, was used to neutralize the challenge particles to the Boltzmann charge equilibrium. An Aerodynamic Particle Sizer was used to measure the number concentration and size distribution upstream and downstream of the sizeselective devices. The silicone oil and TSA coatings were compared in terms of their ability to prevent solid particle bounce. A multi-hole impactor was used to evaluate particle bounce and the loading effect. Experimental results indicate that the solid PST particles bounce less off the TSA-coated plate than off the silicone-coated plate. The coated TSA, however, shrunk after two hours of sampling. Hence, a silicone-TSA coating was applied. The results demonstrate that the silicone-TSA coating minimized PST particle bounce and long-term particle loading. Nevertheless, the silicone-TSA coating could not eliminate insoluble solid PMMA (polymethyl methacrylate) particle bounce.

並列關鍵字

TSA ； Bounce ； Coating ； Silicone oil

參考文獻

Chan TL,Lippmann M(1980).Experimental measurements and empirical modelling of the regional deposition of inhaled particles in humans.Am Ind Hyg Assoc J.41,399-409.

Google Scholar

Chen CC,Lai CY,Shih TS,Hwang JS(1999).Laboratory performance comparison of respirable samplers.Am Ind Hyg Assoc J.60,601-611.

Google Scholar

Chen CC,Lai CY,Shih TS,Yeh WY(1998).Development of respirable aerosol samplers using porous foams.Am Ind Hyg Assoc J.59,766-773.

Google Scholar

Cushing KM,McCain JD,Smith WB(1979).Experimental determination of sizing parameters and wall losses of five source-test cascade impactors.Environ Sci Technol.13,726-731.