Particle filtering capacity of urban vegetation: A microscale numerical approach

It is a generally accepted fact that urban vegetation has the potential to filter fine and ultra fine dust particles (PM10 and smaller) out of the air through deposition processes taking place at the leaf surfaces. It is therefore an obvious idea to investigate the potential of vegetation for improving the local air quality in urban areas, especially in those locations that are heavily polluted by local particle sources. Unfortunately, the prognosis of the impact of vegetation on local air quality is far from being trivial. Despite the fact that vegetation absorbs a certain amount of particles, it has also a large effect on the local wind flow which in return directly affects the dispersion of particles and therethrough the local air quality. This paper suggests a simple approach to quantify the net effect of vegetation on the local particle concentration. We will also discuss the open questions related to this area of research.