Identifying PM2.5-bound metal pollution sources in Southern Thailand using positive matrix factorization and principal component analysis - Siwatt Pongpiachan; Sarunpron Khruengsai; Teerapong Sripahco; Radshadaporn Janta; Rungruang Janta; Jompob Waewsak; Danai Tipmanee; Saran Poshyachinda; Patcharee Pripdeevech (Atmospheric Environment: X, 2025)