The power of an entire forest, in a sculptural planter.
Air pollution might be invisible, but it results in 7 million premature deaths each year. Fortunately, there’s a solution – the CityTree is a high-tech green wall that scrubs the air of harmful particulates – and it has as much air-purifying power as 275 urban trees.
As you might have guessed, the CityTree isn’t really a tree. Instead, it’s a moss culture. Zhengliang Wu, co-founder of Green City Solutions said: “Moss cultures have a much larger leaf surface area than any other plant. That means we can capture more pollutants.”
The CityTree is under 4-meters-tall, approximately 3-meters-wide and 2.19 meters deep. Two versions are available – one with or without a bench – and a display is included for information or advertising.
Due to the huge surface area of moss installed, each tree can remove dust, nitrogen dioxide and ozone gases from the air. Additionally, the installations are fully autonomous, as solar panelsprovide electricity and collected rainwater is filtered into a reservoir where it is pumped into the soil.
The intelligent air filter for cities
The CityTree has a floor space of 3.5m2 including a bench, or in the slim-line version only 1 m².
Moss for clean and cool air
Moss protected by plant coverage binds particulate matter, nitrogen oxides and CO2e and produces valuable oxygen. At the same time it cools the surrounding air.
Cutting-edge IoT technology
Integrated IoT technology collects, analyses and visualises data about the status and environmental performance of the CityTree.
Thanks to a fully automated provision of water and nutrients using a built-in tank, the CityTree is watered independently.
Self-sufficient energy provision
Installed solar panels generate energy for operating the CityTree, and this energy is stored in batteries.
With benches available in a range of different woods, and various colour options for the outer casing, the CityTree harmonises with any urban environment.
TheCityTree is made of a high proportion of recyclable materials, has a long life and can be assembled or dismantled within 8 hours.
A tale of four friends
The story of the CityTree dates back 11 years.
While studying at Dresden University of Technology, Wu met Victor Splittgerber, a mechanical engineer, and Dénes Honus, an architect. After graduating, they ran a workshop at the university on sustainable urban design focusing on new ways to tackle environmental problems in cities.
Four years ago, the trio met Peter Sänger, a graduate in production management for horticulture, and the idea for the CityTree project was born.
Today, bureaucratic obstacles are the main challenge.
"We were installing them (the CityTrees) in Modena, Italy, and everything was planned and arranged, but now the city is hesitant about the places we can install because of security reasons," Wu said.
The team also has plans to introduce the "CityTree" to cities in lower-income countries such as India, which tend to have elevated levels of pollutants.
So far, around 20CityTrees have been successfully installed, with each costing about $25,000.
Can this really fight pollution?
Gary Fuller, an expert on air pollution at King's College London, thinks that the concept of an urban air purifier might be too ambitious.
"Even if you had a perfect air cleaner, getting the ambient air in contact with it is really hard," he told CNN. Pollution from a car exhaust, for example, gets dispersed vertically a few kilometers into the air.
"Efforts would be better put into stopping the pollution from forming in the first place, maybe cleaning up a city's bus fleet," he added.
The CityTree inventors say that they are aware of this and choose the location of each CityTree carefully.
"We intentionally pick spots where pollution is heavy due to traffic and air flow is limited. We are also testing a ventilation system to create our own air flow that gets the pollution to the tree."
Wu also argued that the CityTree is just one piece of a larger puzzle.
"Our ultimate goal is to incorporate technology from the CityTree into existing buildings," he said.
"We dream of creating a climate infrastructure so we can regulate what kind of air and also what kind of temperature we have in a city."