Transportation related emission is the dominant contributing source of air pollutants today. Considering the negative impacts of transportation related emissions on our social and economic environment, extensive efforts have been made by researchers and practitioners attempting to find solutions to reduce the emissions. In order to synthesize these research efforts, various reviews of relevant studies have been conducted by researchers. However, because of the diversity of the topics, most of existing reviews have only focused on specific and narrowed areas. Further, none of existing reviews has attempted to summarize the researchers' opinions on the current research and their prospects of the future research directions. Therefore, this paper is intended to fill this gap by conducting an extensive survey to the transpiration emission professionals. In the paper, a review of existing research and developments on each of the emission related topics is provided followed by a presentation of the respective survey results and analysis. At the conclusion of these reviews and the analysis of the survey, some future research directions in this field are presented at the end.
Abstract