ABSTRACT
PM2.5 pollution has significant impacts on human health and has been a persistent problem in Bangkok and its metropolitan area for many decades. To effectively address the issue, source identification is crucial. This study was aimed at determining the sources of PM2.5 in three regions;Pathumwan district in Bangkok, Mueang district in Samut Sakhon province, and Mueang district in Samut Prakan province. PM2.5 sampling was performed according to the Federal Reference Method (FRM). A combined total of 135 samples were collected across all three locations, over a 24-h period from December 2021 to February 2022 with 46.2 mm polytetrafluoroethylene (PTFE) membranes. The filters were analyzed using particle accelerator-based ion beam analysis techniques;Proton-induced X-ray emission, proton-induced gamma-ray emission, and proton elastic scattering analysis. Positive matrix factorization was used for source apportionment for the three locations. The results indicated that the main contributors to PM2.5 in Bangkok, Samut Prakan, and Samut Sakhon were biomass/solid waste burning (45.6%), traffic (43.7%), and construction (36.0%), respectively. These preliminary findings further supported the need for expanding these types of studies to implement specific strategies for a reduction of PM2.5 level in high activity cities and which could then be applied to other urban areas around the world.