拜香燃煙分佈動態變化與增溼成長特性

Dynamic Change of Size Distributions of Incense Smoke And Its Associated Hygroscopic Growth

李繡偉(Hsiu-Wei Lee)

指導教授 ： 張幼珍

元智大學/工程學院/化學工程與材料科學學系/碩士(1998年)

摘要

本研究中以一自製小型燃燒室，容積為Cheng 等人(1995)所使用燃燒室的千分之一，研究兩種不同價位的拜香─價廉之新山香和兩倍左右價格之烏沈香─所產生之燃煙氣膠性質、採樣位置選擇與測量結果間關係、燃煙初始粒徑與分佈、粒徑分佈隨時間的動態變化、和燃煙微粒增溼成長情形。
氣膠微粒粒徑分佈以QCM和SMPS兩種不同測量原理之測量儀器進行測量，其中QCM可提供0.05~25微米粒徑範圍之質量粒徑分佈，而SMPS可提供1微米以下之個數粒徑分佈之測量。結合兩者來獲得單一儀器所無法獲致之較完整結果，並比較其結果間的異同。此外，亦利用掃描式電子顯微鏡來觀察液滴之形狀、粒徑分佈、與液固相微粒比例等。
本研究發現，由於燃煙在產生後在燃燒室中分佈不均，採樣點的選擇與不同採樣點間測量值之間的關係，對燃煙性質瞭解有其必要性。拜香燃煙初始粒徑分佈中，90%(個數比例)的微粒粒徑都在0.2微米以下。不同拜香燃煙的初始粒徑分佈不同，由兩種儀器和SEM的結果可知，拜香燃煙主要為次微米到微米之液相氣膠和少量不規則形狀大於1微米的固相微粒所組成，其特性粒徑分佈為0.1微米和1 微米處附近各有一峰的雙峰到多峰分佈。燃燒初期，新山香和烏沈香CMD值分別在0.09~0.2微米和0.1~0.15微米間。而新山香的個數濃度較烏沈香高2~3倍。燃煙粒徑分佈會隨時間由較小粒徑向較大粒徑推移，由雙峰演化成單峰分佈。微粒分佈寬度亦呈現隨時間縮小的趨勢。在一小時的監測中，CMD由0.1微米左右的粒徑上升到0.5~0.6微米，兩種儀器所測得之質量中數粒徑，QCM的MMAD和SMPS的MMD，隨時間所呈現的變化趨勢都非常一致。其中QCM的MMAD範圍為0.2~0.35微米，與Cheng等人(1995)之測量結果吻合。
比較以不同測量原理所獲得之MMD和MMAD，對新山香和烏沈香，MMD分別是MMAD的1.3~2倍和2~3倍。由兩種香的結果，來估計燃燒一克拜香所產生的氣膠微粒，大概在 5~21 mg範圍間。不同溼度的實驗結果顯示，不管溼度高低，所得之粒徑分佈都非常相似，顯示拜香燃煙的增溼成長幾乎可以忽略。

關鍵字

拜香燃煙 ； 粒徑分佈 ； 增溼成長

並列摘要

The original particle size and concentration of the smoke is essential for obtaining an estimation of the amount of particles inhaled and deposited in human respiratory system. Lin et al. (1992), Hopke et al. (1993) and Cheng et al.(1995) studied physical and/or chemical characteristics of the smoke using different room or chamber size systems. The count mean diameter or CMD (room size, particle concentration) reported by them were 0.08-0.1 micron, 0.2 micron, 0.13~0.14 micron, respectively. The discrepancies of their results were suspected by Cheng et al.(1995) to be mainly due to the different concentration and size of system investigated.
In addition, accurate estimation of lung deposition estimation with prolonged exposure of the aged smoke requires an understanding of how fast these particles change in size and size distribution and its hygroscopic growth when subject to humid environment such as Taiwan.
Two main goals of this study are: (1) to investigate into the discrepancies of the fresh smoke properties reported by these three groups and (2) to uncover hygroscopic growth of incense smoke under different humidity conditions. Two on-line particle sizers, Mobility Particle Sizer or SMPS(TSI, Inc.) and Quartz Crystal Microbalance, were used in this study. Off-line characterization of incense smoke particles using scanning electron microscope (ABT-60, Topcon) was also performed with the smoke sampled directly on SEM specimen stubs and coated with gold for observation. In the experiments reported below, particle number and mass distributions from SMPS and QCM, respectively, were obtained under RH=10%, 70% and 95%. In each experiment, the ratio of the mass of the incense burned to chamber volume was fixed to about one magnitude higher than that of Cheng et al. (1995) to allow better control of the smoke concentration for later comparison.

並列關鍵字

incense smoke ； Hygroscopic growth