Air pollution has negative consequences for the health of millions of people every year. How a Berlin startup is improving air quality in cities around the world—using moss and the Internet of Things (IoT).

According to the World Health Organization (WHO), atmospheric pollution is the most serious environmental health risk. In Germany alone, according to the latest report of the European Environment Agency, too high levels of fine dust and nitrogen in the air are to blame for an annual 72,000 premature deaths. In Germany, Stuttgart is the negative record holder. The German Environment Agency says that air quality there is the worst in the country. Yet in Bonn, on Friedrich-Ebert-Allee with its constant flow of traffic from morning to evening, passers-by can breathe deeply again and chill out on a nearby bench. How can that be, given the high volume of traffic? The answer is the CityTree, a so-called biotech filter. This unusual item of street furniture is three meters tall with timber cladding. It removes fine dust from ambient air and emits fresh oxygen, using special kinds of moss that function as an air filter and metabolize fine dust. Other examples of this unusual item are to be found in Berlin, Darmstadt, London and Lisbon.

A FRESH AIR STOPPING PLACE FROM BERLIN

The brainchild of Berlin-based startup Green City Solutions, it combines nature and modern technology. A field study by the Leibniz Institute for Tropospheric Research shows that it binds up to 80 percent of fine dust particulate per day in its environment. Several CityTrees combine to create a protective zone. In a clean air zone of this kind, fine dust pollution is reduced by up to 50 percent overall. Within an hour eight of the latest moss modules can cleanse the air that up to 7,000 people breathe. They reduce the ambient temperature by up to 2.5°C and make the CityTree a genuine place to stop for fresh air. And passers-by can enjoy not only a breath of fresh air; on request the CityTree can be fitted out as a WiFi hotspot. A QR code on the attached notice board reveals the CityTree’s latest operating data.

DIGITAL PLATFORM DELIVERS PROOF OF BETTER AIR QUALITY

Other technical components are hidden behind its robust Siberian larch cladding. The CityTree is equipped with IoT sensors that use on-site environmental data to help operate the built-in watering system. That enables the CityTree to be watered automatically and appropriately throughout the year, which delivers a twofold benefit. The moss as it grows reduces fine dust pollution and trucks are no longer needed to supply the water required. The CityTree is checked twice a year and serviced as required if the sensors indicate that a service is needed.  

Each plant filter’s effect on its surroundings can be checked sustainably. Via the AirCare platform a CityTree’s owners, most of whom will be companies or municipal administrations, can monitor digitally how the tree is influencing the quality of the air around it. The tool visualizes ambient air quality on a PC, tablet or smartphone. In the future the company aims to fit out entire cities in Europe and Asia with its vertical plant filters.