News Home & Design High-Tech CityTree Cleans as Much Pollution as 275 Trees (Video) By Kimberley Mok Kimberley Mok Twitter Writer McGill University Cornell University Kimberley Mok is a former architect who has been covering architecture and the arts for Treehugger since 2007. Learn about our editorial process Updated May 31, 2020 Rosser1954 / Wikimedia Commons / CC BY-SA 4.0 Share Twitter Pinterest Email News Environment Business & Policy Science Animals Home & Design Current Events Treehugger Voices News Archive 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. What Is CityTree? That still leaves the problem of declining air quality. One German startup is proposing an intriguing solution: a piece of urban furniture that combines the power of biology and the ease of automated Internet Of Things (IoT) technology to create what's called a CityTree. Here is Green City Solutions' CEO Dénes Honus explaining why CityTrees could be one piece to the urban pollution puzzle: The CityTree is not a tree per se, but actually a densely packed moss culture, vertically housed in an unit that blends in with its urban surroundings. In an area of 3.5 square metres (37.6 square feet), the CityTree does the equivalent job of 275 trees of filtering the air of fine dust, nitrogen oxides and carbon dioxide (up to 240 metric tons per year). How Does It Work? Moss was chosen because of its biological properties, says Zhengliang Wu, co-founder of Green City Solutions: "Moss cultures have a much larger leaf surface area than any other plant. That means we can capture more pollutants." Not only does the CityTree help improve air quality within a radius of 50 metres (164 feet), it can also serve as an analog billboard, displaying lettering, images or digital data via a QR code, iBeacon or NFC (near-field communications). The CityTree comes in the dimension of 4 metres tall by 3 metres wide, and about 2 metres deep (13 by 9.8 by 6.5 feet), and is available either with or without an attached bench. The installation powers itself through its solar panels, and rainwater is collected and automatically redistributed using a built-in irrigation system. Sensors can be added so that data can be collected on the CityTree's performance. According to CNN, cities can invest in CityTrees at USD $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.