Moss – Yes, Moss! – Could Be The Answer For Clean, Smart Cities

When was the last time you thought about air quality? If you’re anything like me…probably never? But air quality can make or break your health.

Just ask Liang Wu — Liang was born in China but moved to Germany as a child. In 2011, he was offered an internship in Shanghai and, excited by the prospect of returning for a couple of months and connecting with the family he still had there, he readily accepted. While living there, he decided to get in shape and started working out a lot outdoors. After a while, his exercise routine soured: Liang had started developing asthma and didn’t know why. 

It was only on returning to Germany that his good health returned and something clicked: Liang realised the air in Shanghai had triggered other issues. 

“That’s when I decided, alright, I have the opportunity to escape to a place where it’s relatively safe, but my family don’t have that choice. I remember being shocked by a story my cousin told me about how they had days [in Shanghai] where they weren’t allowed to go to school because the pollution levels outdoors were so hazardous. Every step you took outside would mean your life expectancy dropped.”

Driven to find a solution, Liang started working with friends he’d met while studying, founding the company Green City Solutions. One of these friends was his co-founder Peter, whose family has worked in horticulture for four generations. Peter’s professor published a paper on the filter efficiency of plants for particulate matter and it explored how trees and bushes might filter the air. 

The surface of a tree’s leaves can absorb pollution, but it’s not an obvious remedy to the issue, since if it’s windy or rainy, “the pollution can resurface, recirculate, it’s not entirely removed from nature.” Moss is a different matter: it captures the particles, consumes them and stores them so pollution can’t resurface once it’s been absorbed.

The friends behind Green City Solutions used this logic to invent the City Tree — a biofilter made from different types of moss which harnesses the plant’s natural ability to filter fine dust to create clean air zones for people to be shielded from pollution. They’ve done pilot projects with the city of Amsterdam, worked with corporations like Deutsche Bahn and have installed the first clean air zone in Berlin with the help of another customer of theirs: the European Commission.

Liang argues it isn’t just good for the air, but for people’s mental health, too: “If you sit in front of the City Tree in summer time you experience cooler air coming out. During fall, we measured a temperature drop of 2.5 degrees celsius and during the summer time we estimate that it’ll be even higher. So sitting there will always transport you to the forest. And I know it’s proven that the psychological effect of looking at green can lower your risk for depression and other mental illnesses.”

The only way is up for Green City Solutions: but how can younger entrepreneurs replicate their success? 

Liang thinks for a moment. “I mean, I could give you the standard rundown of how you have to keep at it, how connecting with people of different fields, etc. But in fact I’ve discovered that a lot of cool innovation comes from looking at nature, biomimicry topics. For instance, there are wind turbines where the blades resemble the shape of a humpback whale. And this, despite the common belief that efficiency gets better the sharper a wind turbine blade is at the tip! Another example is how the Japanese high speed train mimics the streamlined shape of a kingfisher bird’s beak to reduce wind resistance. I think these are really cool examples of how we can learn from nature and imitate something for a positive effect and for nature’s own benefit.”