London (CNN) -- Vertical gardens are cropping up all over cities these days, transforming drab urban facades into vibrant jungles of color.
These lush expanses have found their way onto the walls -- both inside and out -- on numerous sites in recent years revitalizing public buildings, hotels, offices and even a multi-storey car park in Netherlands.
Aside from their pleasing aesthetic qualities, vertical gardens could also deliver more practical benefits says Mark Laurence, creative director at Biotecture, a UK company who design and build green walls.
"The market is rapidly moving into looking at how they can provide eco-system services and green infrastructures for urban environments," Laurence said.
Their modular hydroponic system -- where plants sit in a soil-free set up with nutrients delivered through irrigation channels -- can be retrofitted to just about any wall.
A recent creation erected on the side of Edgware Road Underground station in central London is hoping to improve air quality.
The 200-square meter wall near Marylebone Road -- one of the UK capital's grimiest thoroughfares -- is being monitored by Imperial College, London.
"They have taken initial samples and going at regular intervals to take leaf samples. Then they wash these leaf samples to see how much particulate matter has adhered to the leaves," said Laurence.
The leaves also have an electrostatic charge that also attracts particles.
"A researcher I was speaking to recently reckons green walls in urban canyon environments (areas where walls are higher than the width of the road separating them) are more effective than trees at collecting particles because the way the wind eddies around and then moves down the wall," Laurence said.
Some believe that in less polluted areas, green walls could be employed to grow food, which could aid urban food security. Biotecture have successfully trialled a wall which grew 45 varieties of vegetable.
Furthermore, there's nothing stopping people building their own, more basic green walls at home, Laurence says.
There are various systems for DIY constructions with most requiring a compost-based system, he says, but homemade hydroponic systems can be made using plastic bottles. All you need is irrigation and adequate light.