Metal Composition and Source Identification of PM 2.5 and PM 10 at a Suburban Site in Pathum Thani, Thailand.

This study reports the mass concentrations, elemental characterization and identification of the possible sources of PM_2.5 and PM₁₀ at a suburban site in Pathum Thani, Thailand. The sampling was done from 18 February 2021 to 14 September 2021. PM_2.5 concentrations were between 0.39 μg/m³ and 174.26 μg/m³, while PM₁₀ concentration ranged from 12.75 μg/m³ to 242.02 μg/m³. The average concentration of PM_2.5 in the wet season (61.96 μg/m³) in the study area exceeded the national ambient air quality standards (NAAQS). Particle-induced X-ray emission (PIXE) was used to measure the element concentrations. The main elements, namely Fe, K, Cr and Ca, in both PM_2.5 and PM₁₀ showed significantly higher concentrations in the summer season. A qualitative inter-elemental correlation analysis, principal component analysis (PCA) and cluster analysis (CA) were applied for source identification of PM_2.5 and PM₁₀. The results for the three procedures were in good agreement. Four and three factors of sources were isolated by the PCA for PM_2.5 and PM₁₀, respectively. The main sources identified by PCA were, for PM_2.5, soil dust and biomass burning (32%), road dust and industrial emission (25%), vehicle and industrial emission (10%) and soil dust (9%); for PM₁₀, road dust and industrial emission (36%), crustal and biomass burning (30%) and industrial sources (10%). [ABSTRACT FROM AUTHOR]