Numerical study of pollutant exposure of urban street canyon buildings

The computational normalised pollution concentration profiles along the height of the street canyon are discussed to evaluate the pollutant exposure to buildings facing urban street canyons. With the help of three-dimensional numerical simulations performed using computational fluid dynamics approach, the effects of EMRT on pollution dispersion are analysed onthe both side walls of the canyon of aspect ratio 'one'. The exposure of pollutant on buildings on both the sides of street canyon has been discussed. The RANSequation equipped with the renormalization group, turbulence model and Species Transport Model are adopted. It has been found that for first 25% of the height of street canyon, introduction of elevated metro rail track (EMRT) respectively increases and decreases normalized pollutant concentration for leeward and windward side walls. For the remaining upper portion of the street canyon, the introduction of elevated metro rail track leads to decrease in the pollutant concentration. Introduction of EMRT leads to increase in pollutant concentration on the leeward side wall in its lower region. This increase is especially significant at the pedestrian level at the centre of the street canyon's length. In the present work, the mass fractions of the pollutants on leeward and windward side walls are also investigated and comparison of mass fraction between street canyon with and without elevated metro rail track has been discussed. Copyright (C) 2022 Elsevier Ltd. All rights reserved.