三層濾紙TDI蒸氣與氣膠同步個人採樣器

Abstract

目前關於二異氰酸甲苯(TDI)的氣相及氣膠相分離採樣技術，有雙濾紙採樣方法及環形固氣分離採樣法兩種，前者採樣問題為前置鐵弗龍濾紙會吸附TDI氣體導致氣膠之濃度被高估；後者採樣問題為塗敷過程複雜且體積過於龐大，不適合作個人採樣之用。針對上述問題，本研究研發出一個包括兩個串聯的鐵氟龍濾紙後加一個玻璃纖維濾的新型三層濾紙氣膠及氣體分離採樣器。此採樣器讓我們估計出前置鐵氟龍濾紙所吸附TDI氣體的量，因此可獲得較準確的氣膠和氣體TDI的濃度。 經由雙層鐵氟龍濾紙的氣體吸附測試，發現當兩片鐵氟龍濾紙串聯採樣時，兩者的吸附效率非常相近，另外在TDI氣膠揮發試驗中可得知第一片鐵氟龍濾紙所收集的氣膠的揮發量微乎其微，此兩項實驗發現讓我們可利用模式來推估新型三層濾紙所採得的TDI氣體及微粒的濃度。另外為了能對TDI氣膠作分徑採樣，我們在新型三層濾紙採樣器前端加入慣性衝擊器。本研究顯示，利用未塗敷衍生試劑的玻璃纖維濾紙作為衝擊板，可以減少TDI氣體吸附的問題而避免氣膠量的高估。最後透過高溼度環型擴散管系統與新型三層濾紙系統混合相分徑採樣比較發現，三層濾紙採樣器的採樣結果可以大大減少傳統雙層濾紙採樣器與環形擴散管採樣器之間採樣結果的誤差，此結果驗證了三層濾紙採樣器優於雙層濾紙採樣器。 新型三層濾紙系統的應用不只限於TDI的採樣，也可適用於蒸氣壓低且具有氣膠不易揮發的特性的其他SOCs。

There are two methods currently in use to separate gas toluence diisocyanate (TDI) from its aerosol counterpart. One is the dual filter system and the other is the annular denuder method. The former has the problem that the Teflon filter adsorbs gasous TDI resulting in an overestimation of aerosol TDI concentration. The latter is complicated in coating procedure and often bulky in size making it unsuitable as a personal sampler. To overcome these problems, a new triple filter system consisting of two Teflon filters followed by a glass fiber filter has been invented. The system allows us to estimate TDI gas adsorbed by the 1st Teflon filter hence the exact amount of vapor- and aerosol-phase TDI can be determined. According to the gas adsorption test of two Teflon filters in series, the TDI gas collection efficiency of two Teflon filters is almost the same. The results of the vaporization test using pure TDI aerosol show that it can hardly vaporize during sampling. These two findings allow us to use a simplified model to estimate accurate aerosol- and vapor-phase TDI concentrations. For size-classified sampling of aerosol- phase TDI, we added an impactor in front of the filters. It appears that using a glass fiber filter without coating as an impactor can reduce the adsorption of gasous TDI to avoid overestimation of aerosol- phase TDI. The comparison test of size-classified aerosol and gasous TDI of high humidity condition between the triple filter system and annular denuder system shows that using the triple filter system can minimize the sampling bias between dual filter system and annular denuder system. From the results, the triple filter system is proved to be superior then the dual filter system. Besides TDI, the triple filter system can also be applied to other kinds of SOCs which have low vapor pressure and do not vaporize easily during sampling.