Junjie Liu is an associate professor in School of Environmental Science and Technology, Tianjin University, China. He received his Ph.D. in Engineering Thermal Physics from Tianjin University and was a visiting scholar in Building Technology Group, Massachusetts Institute of Technology, from 1998 to 1999. He is the Committee Member of China Contamination Control Society (CCCS), Member of Chinese Association of Refrigeration and General Secretary of Tianjin Cleanroom Engineering Association(TCEA). And he is also a member of IEST, AW&MA and ISO TC 142. His research aims at building energy conservation technologies and indoor environmental quality protection technologies and equipment.