1. School of Mechanical Engineering, Hanyang University, Seoul, Republic of Korea;
2. Center for Environment, Health and Welfare Research, Korea Institute of Science and Technology, Seoul, Republic of Korea;
3. Center for Particulate Air Pollution and Health, Korea Institute of Science and Technology, Seoul, Republic of Korea;
4. Transportation Environmental Research Team, Korea Railroad Research Institute, Uiwang, Republic of Korea;
5. DK Corporation, Gwangju, Republic of Korea