Study of gas emission transfer processes in the city canyon based on numerical simulation data

City canyon is a typical urban development configuration with two rows of tall buildings located along the road. Green infrastructure (tree alleys, green hedges/roofs/walls) inside urban canyons are a part of a city planning strategy, and it is actively used by architects around the world to ensure pedestrian comfort, reduce noise and the adverse effects of the urban heat island as well as to combat gaseous and dust pollution. However, a relatively large amount of data indicates a possible adverse effect of alleys with tall trees on the airflow characteristics inside urban canyons. The aim of the work is to numerically investigate the distribution of impurities from vehicles in urban canyons. The paper presents a description of microclimatic models built in ANSYS Fluent. It is based on the Reynolds-averaged Navier-Stokes equations closed with a two-equation k - e realizable model, and the multi-species approach is used to simulate the impurities dispersion. Models are considered to take into account the influence of green spaces on the mean flow field and impurities concentration in the urban canyon. The simulation model is tested against the CODASC 2008 experimental data.