The harmful impact of urban air pollution could be combated by strategically placing low hedges along roads in a built-up environment of cities instead of taller trees, a new study has found.
The study, just published in the journal Atmospheric Environment, points out that low hedges reduce the impact of pollution from vehicles in cityscapes where there are large buildings close to roads, far more effectively than taller trees. In some environments, trees actually make the pollution more concentrated depending on prevailing wind conditions and built-up configurations. The study is a collaborative effort by partners from the UK, Europe and USA, led by the University of Surrey’s Professor Prashant Kumar, under the umbrella of H2020 funded project, iSCAPE: Improving Smart Control of Air Pollution in Europe.
Higher trees only have more of an impact in reducing air pollution in areas which are more open and are less densely populated by taller buildings. Urban air quality continues to be a primary health concern as most of the world’s population currently lives in urban areas (54% in 2014), and percentage is projected to rise to 66% by 2050; this is coupled with the fact that one of the main global sources of air pollution in cities is traffic emissions.
Professor Prashant Kumar, who is Chair in Air Quality & Health at the University of Surrey, said future urban planning need to consider designing and implementing more ‘green infrastructure’, such as trees or hedges in the built environment to create a more healthy urban lifestyle. Green infrastructure in cities is an urban planning solution for improving air quality as well as enhancing the sustainability of cities for growing urban populations. These green solutions include street trees, vegetation barriers (including hedges), green (or living) walls, and green roofs. They act as porous bodies which influence local dispersion of pollution and aid the deposition and removal of airborne pollutants, making the air cleaner.
Read the University of surrey press release
