Study on Wind flow and Air Quality in Urban Terrain Bioclimatology is recently becoming more important as it is known that urban climate impacts human activity largely. Especially wind, one of three climate elements, is coming into the spotlight these days. Efficient wind flow network in urban terrain can afford a good air environment. In this study, we examined EIS’s(Environment Impact Statements) performed in Korea. It was found that some EIS’s did not analyse wind flow at all even though most of developing area has its topography showing mountain and valley winds would be dominant in wind environment. Some of EIS’s tried to analysed wind flow qualitatively for better air quality but only suggested ambiguous idea about urban plan. It is noticed that they analysed wind flow qualitatively not quantitatively. Therefore they could not show how much air quality in urban area can be improved through wind flow analysis. We brought up the CFD wind flow analysis method which is able to measure wind effect quantitatively in terms of impacts of ventilation, air quality and walking in street. As far as we know, this work is performed first in Korea. In addition, we applied this wind flow analysis method into two case studies. One of case studies aimed to examine the effect of new skyscraper construction in a civic center. We assumed imaginary urban development in Songmal-ri, Kyungki Province, Korea in the other case study. Songmal-ri is a typical terrain influenced by mountain and valley winds mainly according to its topography and weather observation. We could introduce some important factors which is able to enhance air environment from two case studies. This work can be a basis for urban planing to achieve better environment.