1. Department of Environmental and Occupational Health, Medical College, National Cheng Kung University, 138, Sheng-Li Road, Tainan 70428, Taiwan, Sustainable Environment Research Center, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan, and Department of Occupational Safety and Health, Chung Hwa University of Medical Technology, 89, Wenhwa first St., Rende Shiang, Tainan 71703, Taiwan