In the past decades, the rising levels of air pollution in urban areas are threatening the natural environment and the human health. This Thesis focuses on the development (CAD design) and feasibility investigation (evaluation of introduced losses) of a prototype device for passive air cleaning, after an initial review of the existing technologies in the field. The guideline of the project has been to use the device mounted on cars, taking advantage of their motion for the passive suction of the external air. To give the work a more practical resonance, the study has been based on the Barcelona urban area framework.