Multi-Species Prototypes for Sustainable Environments: How does a living wall design affect air pollution in a typical street section?

This paper studies the effect of trees and living walls designs in the urban environment, as a measure for increasing biodiversity and enhancing urban air quality. The chosen location is a neighborhood plot in the Mediterranean climate of Tel Aviv, with vibrant pedestrian activity. Simulations are performed using the urban pollution dispersion tool in ENVI-met, for a high-traffic and a low-traffic inner city road, with a focus on airborne particle matter (PM) concentrations. Results depict a winter day that air quality standards were moderate. The different scenarios, with and without trees, and different % of living wall designs and vegetative volumes brought about considerable reductions in airborne PM concentrations. However, the reductions still failed to reach WHO recommended air quality standards. Results point out towards a more holistic framework of green infrastructure strategies that may also include green walls, bicycle routes, less vehicle access, and more.