A collaboration of scientists at the Universities of Birmingham and Lancaster has determined that by ‘greening up’ the UK’s streets, pollution levels could be reduced by a staggering 30%. The scientists propose using trees, bushes and other greenery to combat increased heat levels and growing urban ‘concrete jungles’. The ‘green streets’ would also deliver cleaner air in the cities where the pollution levels are at their highest.
The research has been published in the journal Environmental Science and Technology and proposes a street-by-street iniativite of planting trees and bushes. All of them would help to remove nitrogen dioxide and microscopic particulate matter from the air, all of which are harmful to human health.
Thanks to the design of roads and their ‘canyon’ shape, the UK team believe that by installing ‘green walls’ of grass, climbing ivy and other plants, they provide the best opportunity possible to have a natural air pollution filter that can reduce levels by 30%. The team used a computer model in order to best distinguish the effects of plants in canyons from those of plants in parks or on roofs. They found that ‘green walls’ were the best solution in terms of pollutant removal. They have even suggested plant-covered “green billboards” to increase the amount of foliage.
“Up until now, every initiative around reducing pollution has taken a top-down approach – scrapping old cars, adding catalytic converters to cars, and bringing in the congestion charge – some of which have not had the desired effect,” said Professor Rob MacKenzie, from the University of Birmingham’s School of Geography, Earth and Environmental Sciences. “The benefit of green walls is that they clean up the air coming into and staying in the street canyon – planting more of these in a strategic way, could be a relatively easy way to take control of our local pollution problems.”
However while the idea is sound, Dr Tom Pugh from Lancaster University warned that more must be done to stop the removal of green areas in cities. “More care needs to be taken as to how and where we plant vegetation in our towns and cities, so that it does not suffer from drought, become heat stressed, vandalised, or interact negatively with other aspects of our urban areas, and can carry out the very important job of filtering our air.”