The start-up Green City Solutions created CityTree, an innovative plant wall capable of cleaning as much polluted air as 275 trees! Powered by solar panels, this plant wall measuring 4 meters high and 3 meters wide uses foam to capture the pollutants in city air, absorbing up to 240 tons of gas, dust and particles Per year, the equivalent of a forest of 275 trees.
Urban pollution is an enormous problem in many cities around the world, and poor air quality can mean an increase in chronic conditions like asthma, while also making it difficult for people to walk, bike or enjoy the outdoors. One obvious solution is to plant more green spaces, as plants can help to significantly improve air quality and reduce particulate matter, but with urban real estate becoming more expensive, it’s more likely that land will be turned into housing rather than parks.
Design concepts for the cities of the future usually involve a number of ideas that challenge current norms — whether it be in architecture, city planning, or materials engineering. Developed by Berlin-based tech startup Green City Solutions, these mobile installations work as trees in the middle of cities — hence the name CityTree — to filter air. Since actual trees take time to grow, CityTree isn’t exactly a tree — it’s actually a moss culture.
“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,” according to the company’s website. “Moss cultures have a much larger leaf surface area than any other plant. That means we can capture more pollutants,” said Zhengliang Wu, co-founder of Green City Solutions.
The huge surfaces of moss installed in each tree can remove dust, nitrogen dioxide and ozone gases from the air. The installation is autonomous and requires very little maintenance: solar panels provide electricity, while rainwater is collected into a reservoir and then pumped into the soil.To monitor the health of the moss, the CityTree has sensors which measure soil humidity, temperature and water quality.
Cities can invest in CityTrees at $25,000 each, and the company has installed about 20 of these units in Oslo, Paris, Brussels and Hong Kong, with plans to expand to India and Italy. While it might not be as pleasing as a real, live tree, on a practical level, it’s an innovative idea that takes up less space, while combining the power of nature and solar energy with the interconnectivity of new technologies to clean up the air.