On the minimal wind directions required to assess mean annual air pollution concentration based on CFD results

Computational fluid dynamics has shown a great interest among the scientific community to assess air pollutant concentrations in urban areas and, define strategies limit pollution and achieve sustainable cities of future. Recent studies have given methodologies on how mean annual based numerical model results compare with quality standards. Nonetheless, these need many wind directions be modelled therefore, lead high calculation costs. The purpose this paper is present two approaches decrease costs when calculating concentration from computational by (1) ignoring uniformly spaced direction (2) considering predominant directions. According results, first approach overall better than second one for any rose or building layout considered. With approach, can reduced up 50 % without leading more 20 error, even less error expected homogeneous roses. Finally, method finely evaluate errors made using versus whole rose, computing it, presented.