Some of the most cutting-edge carbon sequestration technologies are actually quite old. As in, originating about 700 million years ago. Yes, we’re talking about plants, and specifically, urban vegetation. A new study from Karlsruhe Institute of Technology (KIT) in Germany has found that planting more trees in urban areas may have a larger impact on improving air quality than we thought. Much larger.

Dr. Thomas Pugh, working in conjunction with his colleagues at the universities of Birmingham and Lancaster, conducted this study not in cities themselves, but rather, on a computer. In the course of a sophisticated computer simulation, Pugh and his colleagues studied the effects of greenery in “urban canyons” composed of glass an concrete, which are notorious trappers of polluted air. Within this computer simulation, researchers studied the chemical reactions involved with influencing the concentration of pollutants in the air, and compared the effects of plants grown directly along the streets with those of plants on living walls, green roofs and parks.

Kyocera Living Wall
image via Kyocera

The conclusion? Green walls of climbing plants located in those areas where concentrations of pollutants were highest had exponentially more effect than green roofs or plants grown in parks. Trees planted along roads also produced good results, but only in less polluted streets, where the tree top canopy did not play a part in trapping polluted air at the ground level.

This flies in the face of previous scientific thought on the subject, which held that planting urban vegetation could only cut airborne pollutants by 2 or 3 percent. Pugh’s study reveals that living walls, strategically placed in urban canyons, can increase the local air quality by as much as 30 percent.

How to reap the benefits of this discovery? Pugh and his colleagues propose a type of “green billboard” for widespread urban adoption. Coming soon (hopefully) to a city near you.

“Green areas may be grown road by road without expensive or big initiatives,” said Pugh — yet another point in favor of plants.

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