'CityTrees' made of moss with 'cleaning power of a small forest' permanently installed in London to tackle the capital's filthy air

Three 'CityTrees' made of moss that have the pollution-cleaning power of a small forest have been permanently installed in London to tackle the capital's filthy air. 

The green-sided monoliths have been set up at two pollution hotspots in the borough of Waltham Forest, whose council declared a climate emergency last April.

Dubbed the 'world's first biotech pollution filter', the CityTrees use living plants to filter pollution from the air locally to benefit residents and passers-by. 

The devices — each of which has the pollution-reduction benefits of 275 trees — are the product of Waltham Forest's collaboration with clean tech firm Evergen, the Daily Mail reports.

Similar structures have previously been employed in other cities — including Berlin and Hong Kong — along with temporary trials across London.

″Waltham Forest Council has been tackling climate change for over a decade,″ said Councillor Clyde Loakes.

'The CityTrees are cutting-edge technology with biotech filters, using living plants and different types of mosses to capture toxins and remove pollutants from the surrounding environment to produce clean air.'

'It’s the equivalent of planting 275 trees,' he added.

Two of the permanent CityTrees have been set up at the bus station adjacent to the Leytonstone tube station — alongside which passes the A12 road, which produces the highest levels of nitrogen dioxide in the borough.

The third has been installed at another pollution hotspot — the high-traffic intersection where Leytonstone High Road becomes Leytonstone Road and Crownfield Road becomes Cann Hall Road.

Each self-sustaining CityTree contains a water tank, irrigation systems and sensors to monitor plant growth — all powered by a combination of on-board solar panels and internal batteries.

By fostering different types of moss, the structures are able to remove various pollutants from the air — including particulate matter and nitrogen oxides — all whilst producing oxygen. 

The CityTrees can even provide the council with detailed information on their air-filtering performance, present status and environmental data on its immediate surroundings.