在2010年二月到四月泰國清邁地區的乾燥季節期間，在三個不同的地點進行兩時期密集採樣，採集PM10氣膠微粒，探討氣膠水溶性無機鹽類，羧酸，醣醇類的質量濃度特性差異與可能的污染來源。結果發現清邁市區PM10氣膠的有機及無機物種濃度總是比郊區及山林地區的濃度為高，顯示市區有較多的污染傳入。醋酸是最豐富的單元酸，再者為甲酸，草酸是兩時期最主要的二元羧酸。在PM10事件日，PM10中羧酸的質量濃度比非事件日時高。在白天時期，因化石燃料的排放和生質燃燒過程的污染物，在大氣光化環境下，形成羧酸微粒。脫水內醚醣(Levoglucosan，Levo)和阿拉伯醇(arabitol)是醣醇類的主要成分，兩者在山林採樣點的PM10微粒中佔 0.53-1.48%，顯示山林間存在生質燃燒。Levoglucosan在PM10事件日的夜晚都發現高質量濃度，顯示生質燃燒大部分發生在夜晚。此外，氣膠中醋酸和甲酸的比值(A/F)大於1，同時顯示生質燃燒或車輛排放出的廢氣是主要的污染來源。而在兩時期，malonic/succinic 的比值介於0.94-1.72，顯示清邁地區大氣環境同時充斥著交通原生污染源及二次光化產物的影響。由兩時期的物種指標：K/Levo= 0.78-2.68, Levo/Mannosan= 5.73-36.2的比例關係發現有明確的生質燃燒特徵，其中脫水內醚糖是視為清邁地區周圍的山林燃燒最具指標意義的氣膠有機物種。研究歸納發現清邁地區大氣污染來源最主要來自光化產生的二次氣膠和生質燃燒中硬木和軟木的樹葉/皮燃燒所貢獻。 PM10 aerosol was collected during two periods between February and April of dry season 2010 at urban, suburban and mountain sites in Chiang Mai basin, Thailand. Characteristics and provenance of water-soluble inorganic species, carboxylic acids, anhydrosugars and sugar alcohols in PM10 were investigated. Concentrations of inorganic and organic species in PM10 aerosol at urban site are always higher than at suburban and mountain sites, indicating that more sources were transported to urban area. Acetic acid was the most abundant monocarboxylic acids, followed by formic acid. Oxalic acid was the dominant dicarboxylic acid species during both periods. Concentration of carboxylic acids during the PM10 episode was higher than that during non-episodic pollution. Carboxylic acids with a peak at daytime during the PM10 episode indicate that carboxylic acids are formed by photochemical reaction and/or are emitted directly by fossil fuels and biomass burning processes. Levoglucosan (Levo) and arabitol were the most dominant anhydrosugar and sugar alcohol, respectively, the ratios of levoglucosan to PM10 in forest fire are 0.53-1.48% by PM10 mass. High concentration of levoglucosan was found at nighttime in both periods, indicating that biomass burning contributed during nighttime. Mass ratio of acetic to formic acids (A/F) > 1 is often used to demonstrate the primary source by wood burning or vehicular emission. This study showed that the contribution of primary sources caused from biomass burning. Moreover, the ratios of M/S in the range of 0.94-1.72 during both periods indicated there exists simultaneously the impaction of primary traffic-related emissions and secondary photochemical pollution on Chiang Mai ambient environment. The discriminator ratios of biomass burning reported here are 0.78-2.68 of K/Levo, 5.73-36.2 of Levo/Mannosan. Levoglucosan was found to be the most useful marker for biomass burning emitted from forest fire event in the mountain around Chiang Mai basin. The most significant contribution to PM10 in Chiang Mai basin was the photochemical formation of secondary aerosols and primary source from biomass burning contributed by hardwood and softwood of leaves/bark trees.
