Green streets for pollutants reduction

Reflections In this chapter, the mitigation effect of greening solutions on air pollution within urban canyons is reviewed. First, a glance at the specific scientific literature is made and the different outcomes by authors about the effectiveness of greening solutions on air quality improvements are stressed. The main parameters to consider, the most promising strategies and the most suitable plant species characteristics, are discussed. Considering the important role played by numerical simulation in this field, the main issues that have to be taken into account in implementing a computational fluid dynamics model of the problem are listed and commented. Finally, with reference to evergreen hedges and a row of trees, some preliminary results obtained by means of a simple numerical model applied to CO2are presented and discussed.