Innovative Filter Removes Pollution Using Moss

14 January 2020 in Leafhouse, Tinyhouses

“one consistent theme in my imaginings has been a resistance to silo nature and technology, but instead to envision their integration, their union”

The first CityTree installed in Amsterdam in 2018. Photo: Green City Solutions

When I imagine the future of cities, I’m always drawn in by preferred, rather than possible or probable, scenarios. In other words, I like to ask myself questions like: what do I want to see and experience? what would be the most beautiful? what designs would benefit humanity at large? And the one consistent theme in my imaginings has been a resistance to silo nature from technology, by instead envisioning their integration, their union.

As a result, I always look for companies and governmental projects that reflect a similar vision of the world. One such company recently came on my radar: Green City Solutions (GCS). This sustainable technology company, headquartered out of Berlin Germany, uniquely combats air pollution in cities with a beautiful new product: CityTrees. They act as bio-tech filters, seamlessly integrating into streetscapes as benches and architectural pieces.

Photo: Green City Solutions

But why is this important? According to the UN, roughly 55% of the world’s population lives in urban areas and about 90% of city-dwellers breathe in air pollution everyday. I’ve you’ve lived in a megacity like me, you’ve probably experienced the effects of poor air quality. WHO estimates that about 7 million people die annually from exposure to harmful air particulates. GCS, to combat this health problem, combines IoT (Internet of Things) with horticulture to monitor and quantifiably improve air quality.

CityTree in London Photo: Green City Solutions

CityTrees work by combining different types of moss that bind toxins in the air, like particulate matter and nitrogen oxides, while simultaneously producing oxygen. The built in ventilation and aquaponic systems allow for reduced maintenance and a natural cooling effect. Furthermore, the software element enables remote monitoring, real-time data collection, and customizable automated processes, which maximizes its effectiveness and efficiency. This means that you can change and tweak their settings.

The CityTree concept demonstrates the general trend of our cities, like our phones and automobiles, becoming “smart.” Every bench, bridge, building facade, and bus stop could become a potential sensor of, and filter for, air quality. For the Sci-Fi buffs, futurists, and urban designers, it’s an example of the idea that cities will become a kind of cybernetic collective, a hive-body with exponential connection and network effects. Regardless of how cool that sounds, it won’t happen unless the technology works.

Photo: Green City Solutions

Most importantly, the preliminary results from the independent research institute Climate-Kic demonstrate that air passing through the CityTrees see a reduction in ultra fine particles (UFP) by -38%, PM 2.5 by -25%, and black carbon (BC) by -18%. And while I’m keen to see more research with respect to how the technology compares to its natural competitors (trees, bushes, etc), these early numbers prove the innovation’s serious potential to make our physical spaces more useful and beautiful.

Now, in 2020, cities and businesses all over the world are adopting this strategy into their infrastructure, as CityTrees are being installed in London, Amsterdam, Shanghai, and Berlin.

Photo: Green City Solutions

If you are someone who, like me, believes in the marriage of nature and technology, I encourage you to follow Green City Solutions (GCS). They are one of many emerging companies working to materialize a new global paradigm. GCS embodies the credo of biomimicry expert Janine Benyus: “when the forest and the city are functionally indistinguishable, then we know we’ve reached sustainability.”


Craig Dinwoodie is an artist and poet who is passionate about housing futures and planet Earth. He is a graduate of Allegheny College, where he studied English Literature and Environmental Ethics. Craig believes future innovations in housing play a pivotal role in both combating the climate crisis and economically unburdening people. His mission is to explore how our engagement with new design systems and materials can connect to a broader and more complex ecological ethic. You can catch him in Shanghai China for now, probably at a cafe reading or writing.

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