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Moss-filled smart wall cleans London’s air

(14 Apr 2018) LEADIN:

London has a new weapon in its fight against air pollution.

The British capital recently welcomed its first-ever CityTree, a moss-filled smart wall that “cleans” polluted air.


Amongst the hustle and bustle of central London, this new addition to the city’s street furniture is quietly battling air pollution.

CityTree, developed by German start-up Green City Solutions, claims to have the air cleaning ability of about 275 trees.

That’s because this “living wall” is packed full of pollution-absorbing moss, which naturally removes harmful particulate matter and nitrogen dioxide from the air.

It claims to reduce harmful pollutants by up to 30 percent.

“The CityTree uses mosses to clean the air,” explains Sukhbir Sidhu, the founder and CEO of Evergen Systems, which supplies CityTrees in the UK.

“Mosses are vascular plants, they have no roots, so they take all the nutrients and water from the air, that makes them ideal air purifiers.

“In fact, mosses have been used as bio indicators of pollution for over 50 years, but it’s only now that they’ve used mosses to actually clean the air.”

It’s claimed to be the world’s first intelligent biological air filter.

The 3.5 square-metre device is being trialed in London’s busy West End after appearances in other European cities, including Berlin, Paris, Amsterdam and Oslo.

Rather than attempting to clean all of London’s polluted air, Sidhu says the goal is to create “micro environments of clean air,” particularly where Londoners and tourists gather.

They can be installed outside schools, inside train stations and in front of offices and shops.

“It’s impossible to clean the airmass of an entire city, no technology exists,” says Sidhu.

“So, our focus is to create micro environments of clean air where people need to walk, sit or linger.

“So, what we’re trying to do is give them a respite in a small area, that’s about the best you can do with any filtration. So, the idea will be to then have more city streets in the city.”

Aside from binding particulate matter and other pollutants, the moss generates oxygen and cools ambient air.

It’s maintained by an integrated water tank, which automatically waters the plants. Other plants give the moss protective shade.

“The mosses are actually living off pollutants like particle matter, which is fine dust, or nitrogen dioxide,” explains Sidhu.

“As the air goes over the mosses, the pollutants stick to the moss surface and is eventually consumed by the mosses and it becomes part of their bio-mass and thus the process of them reducing the air pollution in this area.”

The CityTree isn’t just a living wall, it’s also a smart one.

The green-themed street furniture boasts Internet of Things (IoT) technology that constantly monitors air quality and collects equipment-related data.

That data will be used to develop pollution maps and help analyse the wall’s performance. It’s powered by solar panels on the roof.

“You’ve got pollution sensors mounted on both sides of the CityTree and they will monitor pollution on either side,” explains Sidhu.

“You’ve got sensors behind the plants, which monitor the health of the plants.

“There are sensors for battery level, for water level, wind speed, temperature and all of this data is uploaded to the cloud.”

CityTree is located close to London’s Piccadilly Circus, a popular location for tourists, but also a busy junction constantly streaming with buses, taxis and delivery vans.

The “living wall” was brought to the city by the area’s local council and The Crown Estate, one of the biggest land owners in London’s West End.

About three million deaths a year are linked to exposure to outdoor air pollution.

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Post Series: United Kingdom
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