More than half of the world population lives nowadays in urban areas and that’s the reason why the quality of the urban environment has become a key issue for human health. In this context, it is important to estimate and document any action that contributes to improving thermal comfort and air quality. The aim of this paper is to present a system for the design of urban spaces developed in the framework of the SMARTUrban project. Such a system aims at giving a strategic tool to administrators and design professionals for sustainable management and urban planning. SMARTUrban is a prototype of an urban space design software that estimates the effect of design modification or of new design on thermal comfort, carbon sequestration and air pol utant removal.