1. a Department of General Science, Faculty of Science , Chulalongkorn University , Bangkok , Thailand
2. b National Institute for Environmental Studies , Tsukuba , Japan
3. c Environmental Science Program , Chulalongkorn University , Bangkok , Thailand
4. d Pollution Control Department , Ministry of Science, Technology, and Environment , Bangkok , Thailand
5. e Department of Hygiene and Public Health , Teikyo University School of Medicine , Tokyo , Japan