Abstract
To characterise the atmospheric aerosol in northern Thailand, ambient particulate matter of an aerodynamic diameter less than 2.5 mm (PM2.5) and 2.5-10 mm (PM2-5-10) were collected by Dichotomous air samplers at Ban Hua Fai air monitoring station in Mae Moh area during January-April 2001. In this area there are combined with the biggest power plant and lignite-coal mine in Thailand. Up to 40 elements, 4 ionic species, and elemental and organic carbons (EC, OC) were analysed by ICP-MS, ion chromatography and CHNS/O analyser, respectively. The average mass concentrations of PM2.5 (fine particle) and PM2.5-10 (coarse particle) were 56.29 and 25.55 mg/m3, respectively. Mass concentration ratios of fine to coarse particles were ranged of 1.06-5.95. The most abundant chemical compositions of fine particles were EC, OC, NH4+, K+, K, SO42- and NO3-. While EC, OC, Ca, Al, Fe, SO42-, NO3-, and Mg were abundant in coarse particles. Correlation coefficients between the chemical components were calculated separately for fine and coarse particles. In fine particles, PM2.5 mass correlated significantly with OC and EC. Also OC, EC were strong correlated with K and K+, and moderate correlated with NH4+, and NO3-, which were indicative to biomass and possible vehicle emissions. In coarse particles, there were strong correlations between the common major and minor of crustral related elements, including Mg, Al, Ca, V, Mn, Fe, Co, Rb, Sr, Cs, Ba, La, Ce, Nd, and Th.
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