Designed by the start-up Green City Solutions, the CityTree project aims to reduce pollution in cities by using foam lined on walls 4 metres high and 3 metres wide and 60 centimetres thick. Purpose: to purify the surrounding air, making pollution a nutritional source.
Installed in the form of a vegetable wall, 1600 pots of foam are maintained by a steel structure. Bacteria, present on the surface of the foam, attract the particles of polluted matter and absorb them. After this ingestion, the bacteria die and serve as food for the moss. Finally, pollution becomes a nutritional source. At a time when trees are becoming scarcer and pollution is increasingly present, invisible and insidious, several cities in Germany, Norway, London, Hong Kong and even in Paris, Place de la Nation have already adopted the concept.
Installed on a panel 4 meters high for 3 wide, the foam will purify the surrounding air by photosynthesis, absorbing nearly 240 tons of gas, dust and particles every year. Approximately 275 trees would do the same within a radius of 50 meters. The installation of sensors also allows the panel to regulate the needs of the foam by providing only the water and nutrients it needs. Each installation also has a rainwater recuperator. The installation, autonomous, would ultimately require only a few hours of maintenance per year.
Each wall would replace the equivalent of 275 trees while requiring 99% less space
According to Denis Onus, one of the architects: “each wall would replace the equivalent of 275 trees while requiring 99% less space”. In other words, a CityTree can reduce air pollution by 30% within a radius of 50 meters. And if we prefer real trees to artificial, remember that air pollution is an invisible killer responsible for nearly seven million premature deaths a year, according to the World Health Organization (WHO).
However, we have been recently informed that the CityTree installed on the Mont des Arts in Brussels is not going well. For several days, this plant wall created to purify the air in the city centre of the Belgian capital seems to dry up. Was it due to the heavy heat that Belgium has experienced this week? This was the opinion of the municipal authorities.
“We asked our services to come and water the plants and fill the tank. As the situation has improved a little, we have contacted the company that provided us with the city tree, Green City Solutions “, explains Arnaud Bastogne, energy manager at the City of Brussels. “They went early in the week and confirmed that there was an irrigation problem. The sending of water from the tank was not enough given the extreme temperatures, so we asked them to increase the frequency of irrigation.
However, to avoid new problems with these plants, Green City Solutions proposed to the City of Brussels to come and change all the plants. This will be done at the beginning of next week. “As a reminder, we will evaluate the CityTree after the three-month period. This technical problem will be taken into account in our report, “adds Arnaud Bastogne.