“…Balczo et al, 2009;Buccolieri et al, 2011Buccolieri et al, , 2009Gromke and Ruck, 2012Gromke, 2011;Gromke et al, 2008;Li et al, 2013;Moonen et al, 2013;Salim et al, 2011;Vos et al, 2013;Wania et al, 2012), qualitative and not only quantitative changes in the flow field were observed at the neighborhood scale. The qualitative changes indicate on the one side the necessity to perform studies at the urban neighborhood rather than at the street canyon scale and on the other side to account for avenue-trees, or more general all types of vegetation typical for built-up environments, in microscale urban air quality studies.…”