Green City Solutions from Berlin is a start-up company that has developed the world’s first bio-tech filter to quantifiably improve air quality. We talked to founder ZhengLiang Wu to catch up on how the company is doing since participating in the Postcode Lottery Green Challenge in 2016, when the company was runner-up and took home the prize money of €200,000.

"We have installed more than 50 CityTrees in over ten countries"

Can you tell us about the CityTree?
“The CityTree is based on the extraordinary idea of combining plants with cutting-edge Internet of Things technology. Special moss cultures filter particulate matter out of the air. We have created an air filter that is both natural and intelligent. We keep on working hard and focused on our vision of a world in which people in cities can live healthily. We want to create living conditions that allow all people living in cities around the world to permanently enjoy cleaner air.”

What has the prize money of the Postcode Lottery Green Challenge done for your business?
“We have invested the €200,000 into independent performance research in real life test conditions driven by the Scaler Project initiated in December 2016. This project is funded by the European Union and conducted in close collaboration with the Climate-KIC organization, the largest network of the EU related to climate innovation initiatives. One of the highlight outcomes of this independent research is that the polluted air that has passed through our CityTree becomes cleaner and contains up to 23% less particulate matter.”

Where can we find the CityTrees and who are your most important customers?
“More than 50 CityTrees have been installed already in over ten European countries and we’re starting to enter the Asian market as well. Several municipalities have installed the CityTree into their urban landscape as an air purification measure. As well as well-known companies such as Deutsche Bahn, supermarket chain Albert Heijn, Wonam, water company Waterbedrijf Groningen, the Swiss railway company SBB, and Cisco.

What are big changes since you participated in the Postcode Lottery Green Challenge?
“There have been some significant improvements on the performance, technology and services of our product. To name a few examples: we now do location analysis with advanced simulation techniques for an optimum effect. Also, by activating a ventilation system in the construction airflow can be increased and, with that, the air filter’s performance to a larger amount of cleaner air. The amount of air flowing through can be controlled to suit the respective air pollution situation. And finally, the integrated sensors generate huge amounts of data in real time, which can be viewed using a specially developed dashboard. The data provide comprehensive information about the environmental performance and the status of each CityTree.”

Can you tell us about your business goals for the near future?
“Our key business goal is of course to continue to improve the CityTree with a consequent step-by-step development approach: it starts with prototyping ideas for improvements, followed by producing a pre-series product design, accompanied by laboratory research. Then we conduct performance research in real urban environments, with single pilots before expanding to multiple pilots.

Another key goal that we recently fulfilled was to manage the implementation of a highlight project, jointly with the Municipality of Amsterdam. Last summer, Amsterdam was the first city to host a pilot project of eight CityTrees, to improve the air quality of a whole street canyon. The central question is to which extent the set-up in this busy, Dutch street can make a significant contribution to the improvement of local air quality. TNO, GGD and Wageningen University are participating in this research and data is collected as we speak.

How do you look back at the final of the Postcode Lottery Green Challenge?
“For me personally, participating has been an important milestone in my own development and the development of Green City Solutions. Meeting all the likeminded people at the final was an inspiring event I still think of today. The accelerator program Deepdive gave us additional tools to master the daily challenges of being a social entrepreneur. The proof of impact for Green City Solutions is the fact that The Netherlands is our most promising source of business outside of Germany.”