By Gemma Childe on 26th Jul 2012
Pollution could be reduced by up to 30 per cent, if more vegetation was introduced, scientists have said.
Previous studies have shown that greening urban spaces can cut pollution by just 5% but this could be increased with the creation of "green walls" - more trees and other vegetation.
If grown at street level in urban areas, the walls would clean air in areas that are normally exposed to higher levels of pollution.
Plants in built-up areas have been shown to remove nitrogen dioxide and particulate matter which are harmful to our health, according to the UK researchers.
Green walls, consisting of ivy and other climbing plants, built on billboard-like structures could act as air pollution filters, the team said.
The discovery was highlighted in the journal Environmental Science and Technology.
Co-author Professor Rob MacKenzie, from the University of Birmingham, said: "Planting more [green walls] in a strategic way could be a relatively easy way to take control of our local pollution problems."
Nicola Cheetham, head of environment (surface transport) for Transport for London (TfL), said that TfL had recently installed its second green wall to lower the pollution levels associated with heavy flows of city traffic.
Co-author Tom Pugh, from Lancaster University, said one of the challenges of greening urban areas was ensuring the plants were able to survive in the projected change in conditions.
Anne Jaluzot from the co-ordinating group Trees and Design Action Group said money was being wasted on designer green walls: "These green walls often look great, but they're unsustainable because of the high maintenance costs and need for fertilisers.
"Councils and developers would often be better to simply cover a wall with ivy and other creepers," she said.