“…These studies often employ simple building confi guration to study how the geometry and different roof shapes can affect airfl ow and pollutant fi elds in a 2D idealized street canyons (Theodoridis & Moussiopoulos,FIGURE 1. Defi nition of the street canyon confi guration cases 2000; Chan, Dong, Leung, Cheung & Hung, 2002;Assimakopoulos, ApSimon & Moussiopoulos, 2003;Xiaomin, Zhen & Jiasong, 2005;Nazridoust & Ahmadi, 2006;Huang, Jin & Sun, 2007;Huang, Hu & Zeng, 2009;Yassin, 2011;Takano & Moonen, 2013). The most commonly RANS turbulent models used in street canyon simulations are the standard k-ε model, renormalization group RNG k-ε model and realizable k-ε model and their performance are tested in some of the studies.…”