The Crown Estate deploys London’s first air purifying CityTree

An outdoor "living wall" with an air purifying capability of 275 natural tress that can reduce harmful pollutants by up to 30% had been launched by The Crown Estate near Piccadilly Circus.

The CityTree is a new technology that cleans the air, while occupying just 1% of the space that would be needed using real trees. The Crown Estate and Westminster City Council are trialling the moss-covered technology on Glasshouse Street to see what impact it has on local air pollution levels.

With large areas of London commonly breaching annual legal limits for air pollution within the first few weeks of January, the CityTree, designed by cleantech company Evergen Systems, could embed air purifying technology as part of a smart cities transition.

The Crown Estate’s director for Central London James Cooksey said: “As one of central London’s major landowners, we want to play our role in improving London’s air quality to ensure our city remains a brilliant place for everyone who lives, works and visits here. There is no simple solution, so alongside our work to reduce carbon emissions from our buildings and reduce the number of vehicles on our roads, we want to test and learn from new technology.

“That’s why we’re delighted to be launching the first CityTree in London with the support of Westminster City Council and Evergen. Its arrival in London is testament to the power of partnership, and it is partnerships like this which will play a vital role in tackling pollution in our city in the future.”

The CityTree – which has been featured on edie’s green innovation round-up – utilises a combination of mosses to absorb particulates, while plants provide shade to enable the moss to grow in an urban environment.

Particulate matter in the immediate surroundings could be reduced by up to 30%, Evergen claims, while built-in watering and Internet of Things (IoT) monitoring mean it is largely self-sustainable. European cities such as Berlin, Paris, Amsterdam and Oslo all have CityTrees in place.

The London unveiling isn’t a UK first, however. Northumbrian Water Group (NWG) has been working on a similar CityTree project, again supplied by Evergen, since 2017. The company reached an agreement with Newcastle City Council to place the tree at the Haymarket. Newcastle’s CityTree was unveiled on Wednesday (14 March).

Northumbrian Water’s Group Director of Information Services Nigel Watson said: “The Newcastle Moss Tree is a fantastic opportunity to explore a truly innovative way of tackling pollution and sharing the findings with people who can take the concept and expand upon the value it brings to the environment.”

Clean Air Act

The CityTree was unveiled just one day after four parliamentary groups accused the Government of viewing air quality as a “box-ticking exercise” and called for a new Clean Air Act to be introduced.

Westminster City Council’s cabinet member for the environment, sport and community David Harvey added: “It will be fascinating to see what impact The CityTree has on pollution in the local area. This is just one example of the new technology we want to test across Westminster.

“Air quality is the number one concern for our residents and with over a million people moving into and travelling to our neighbourhoods each day it is crucial that we make more strides to clean up our air and tackle poor air quality for residents and visitors alike.”

Matt Mace

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