| 摘要: | 摘要
拜香燃燒為台灣空氣污染的主要污染來源之一，特別在一些宗教民俗節慶的舉行期間及香火鼎盛的廟宇室內與周界環境，過去的研究主要在燃煙排放的重金屬及多環芳香烴化合物的探討，然而拜香燃煙樣品的相關研究甚少完整探討排放微粒中無機鹽類、有機酸、脫水醣類(anhydrosugars)及醣醇類(sugar alcohols)排放特徵，以提供污染貢獻及污染源鑑別的證據。因此本研究藉由常見的四種拜香燃煙樣品及四種未燃燒之拜香樣品，探討燃煙微粒之無機鹽類、有機酸、脫水醣類及醣醇類排放特徵，並評估微粒有機指標(organic makers)做為拜香燃煙生質燃燒污染鑑別之可行性。
研究結果顯示，四種拜香的燃煙微粒排放係數介於37.8-46.3 mg g-1 incense，新山香的排放係數最高，料香的排放係數最小。在拜香燃燒後之燃煙，所排放的微粒成份多寡，所測得之成份依序為脫水醣類、無機鹽類、有機酸及醣醇類，分別佔以分析量的43-53%、30-33%、10-17%及4.4-7.1%；拜香燃煙樣品在脫水醣類，levoglucosan (1,6-anhydro-β-D-glucose, Levo) 佔總脫水醣類80.3-91.0%，是所有已分析的拜香燃煙樣品物種中最豐富的化合物，且是生質纖維素燃燒的特殊產物，且在未燃燒的拜香樣品中未存在。
在拜香燃煙樣品的無機鹽類以K+及Cl-為主，二者合計佔總無機鹽類的63.1-75.5%，在有機酸部份，拜香燃煙主要排放formic acid和acetic acid，二者佔已鑑別的有機酸總量37.9-64.4%，xylitol是醣醇類重要物種佔總分析醣醇類的1.2-36.6%。除了levoglucosan, xylitol及formic acid均未在未燃燒的拜香樣品中出現，顯示這些物種是拜香燃煙的潛在指標物種。四種拜香燃煙樣品之acetic acid/formic acid比值為0.38-1.13，Levo/Mannosan之比值為10.43-19.60，Levo/Xylitol之比值為21.50-35.30，這三種此值在不同拜香燃煙其值均呈現一相近的比值，顯示可成為拜香燃燒的指標比值。
此外，本研究發現拜香燃煙樣品的formic acid極有可能來自未燃燒之拜香樣品中oxalic acid熱解所轉化。
拜香燃煙微粒樣品物種之濃度主要出現在submicron mode (0.1-1.0 µm)的粒徑，大多數的物種約有60-95%的物種濃度出現在此粒徑範圍，此外，各物種在nanoscale mode (10-100 nm)的粒徑範圍有初始微粒之形成。
Abstract
Incense burning is an important kind of air pollution in Taiwan, especially in the ceremonial worshiping of gods in Budhism, Taoism and folk religions. Studies to date have mainly focused on emissions of metals and particle-bound polycyclic aromatic hydrocarbons (PAHs), size distributions, and toxicities. A detailed analysis of the inorganic and organic composition of incense smoke has not been performed. Such an analysis is necessary if informed strategies and policies related to incense burning and air pollution are to be developed. This study therefore aims to identify the chemical species contained in incense smoke and unburnt incense, and furthermore to identify potential marker compounds. The four most popular types of incense in Taiwan are marketed under the names Lao Shan, Hsing Shan, Liao and Chen. The total particulate matter (PM) mass emission factors were 43.71.08 mg g-1 of Lao Shan, 46.32.68 mg g-1 of Hsing Shan, 37.80.83 mg g-1 of Liao and 45.90.60 mg g-1 of Chen. Chemical analysis of emissions from the four types of incense revealed that of the 25 components in four groups characterized, anhydrosugars formed the major group, at 43-53 % w/w of identified particulate and 858.6-1586 g g-1 of incense, followed by inorganic salts at 30-33 % w/w of identified particulate and 662.6-956.9 g g-1 of incense, carboxylic acids at 10-17% w/w of the identified particulate and 268.6-392.8 g g-1 of incense, and sugar alcohols at 4.4-7.1% w/w of the identified particulate and 102.3-142.5 g g-1 of incense.
The anhydrosugar levoglucosan (1,6-anhydro-β-D-glucose, Levo), used as a marker of biomass burning, was always the most abundant species in emitted PM for four incenses, accounting for 80.3-91.0% w/w of total identified anhydrosugars. K+ and Cl- were the second most abundant components (K+ and Cl- were summed), accounting for 63.1-75.5% w/w of total identified inorganic salts. The most abundant carboxylic acids in the emissions were formic and acetic acid, accounting for 37.9-64.4% w/w of total identified carboxylic acids. Xylitol was the dominant sugar alcohol at 18.2-36.6% w/w of total identified sugar alcohols. In addition to Levo, xylitol and formic acid are not found in four unburnt incenses, indicating these abundant species are potential markers for incense burning. The calculated discriminator ratios for four types of incense burning reported here are 0.38-1.13 for acetic acid/formic acid, 10.4-19.6 for Levo/Mannosan, and 21.5-35.3 for the novel discriminator ratio Levo/Xylitol. Furthermore, formic acid, the abundant carboxylic acid in incense burning, may be mostly generated from oxalic acid in unburnt incense.
Studies of size distributions show the components in incense smoke particles mostly occurred in the submicrometer size range (0.1-1.0 μm), accounting for ca. 60-95% w/w of total amounts of the identified species mass, individually. There is the contribution of the primary nanoscale particle (10-100 nm) in incense burning. |
