International Journal of Environmental Science and Development

Abstract—Open burning is an important source of atmospheric particulate matter (PM) emissions in the South East Asian Region. PM2.5 samples were collected in dry season (March 2013) at two sampling locations in Chiang Mai Province, Thailand. Doi Ang Khang (DAK) site is located uphill near the Myanmar border representing a near source site and Chiang Mai University (CMU) is located downhill in the city of Chiang Mai representing a receptor. The samples were collected by mini volume air samplers on a daily basis (24 hours) and analyzed for elemental composition. It was found that the average PM2.5 concentration at CMU (74.5±43.5 μg m^-3) was higher than that at DAK (59.1±44.1 μg m^-3). However, they were well correlated (r = 0.780) and not significantly different (p > 0.05). The major elements found in the PM2.5 samples collected from both sites were K, Mg, Al and Fe. The element with the highest mass content was K (2.06 μg m^-3 at DAK and 2.23 μg m^-3 at CMU). Therefore, it can be revealed that biomass burning was a major source of PM2.5 collected at both sites, K is known as a biomass burning tracer. Concentrations of PM2.5 and K at both sites were not much different. This is probably due to large areas of open burning in the upper part of Northern Thailand and in neighboring countries causing haze that covered the whole area. Although there was no significant difference of air pollutants at both sites, correlation between PM2.5 and K was higher at the near source site than the receptor site, supporting that K was emitted from biomass burning. Backward trajectory was performed to identify air mass movement to the sampling sites. The major air mass (45%) to DAK was from a western direction, while the air movement (52%) to CMU was from a southwest direction.

Index Terms—PM2.5, biomass burning, elemental composition, air pollution.

C. Khamkaew is with the Environmental Science Program, Faculty of Science, Chiang Mai university, Chiang Mai, 50200, Thailand (e-mail: chanakarn53@gmail.com).
S. Chantara and W. Wiriya are with the Environmental Chemistry Research Laboratory (ECRL), Chemistry Department and the Environmental Science Program, Faculty of Science, Chiang Mai university, Chiang Mai, 50200, Thailand (e-mail: somporn.chantara@cmu.ac.th, wanwiriya484@hotmail.com).

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Cite: Chanakarn Khamkaew, Somporn Chantara, and Wan Wiriya, "Atmospheric PM2.5 and Its Elemental Composition from near Source and Receptor Sites during Open Burning Season in Chiang Mai, Thailand," International Journal of Environmental Science and Development vol. 7, no. 6, pp. 436-440, 2016.