• Air Pollution Solutions: What is CityTrees?

Waste Management

Air Pollution Solutions: What is CityTrees?

Nov 22 2018

The World Health Organisation estimates that over 90% of the world’s population breathes in air exceeding the global guideline limits. So, we’re taking a look at some innovative solutions to the air quality crisis. Look back at part 1 of the series to find out about the Smog Free Project, a series of inventions to reduce the smog in the air.

In this post, we’re focusing on CityTrees, a block of moss cultures that can filter pollutants out of the air.

Going Green

CityTrees work by combining biotechnology and IoT technology, giving the non-urban thriving moss cultures the chance to survive in busy cities. The installed technology is combined with shade-giving plants, an automated water supply and nutrients to allow the moss to grow and filter the air.

Many of Europe’s major cities are operating CityTrees, with 4 recently installed on Amsterdam’s notoriously polluted street, Valkenburgerstraat. The trees are typically installed outside schools, inside train stations, in front of busy offices or inside shopping centres.

They aim to provide clean air to the busiest areas, that are usually lacking in greenery. One CityTree has the air cleaning power of 275 urban trees, meaning you can have an entire forest worth of cleaning power in just 3.5m². But, how does the technology work?

Moss cultures have the ability to filter pollutants, including particulate matter, out of the air. The thick, dense plants bind the particles to the surface of the leaf and can then integrate them into their own biomass. Not only does the moss remove the pollutants from the air, it also makes use of it in its own eco-system.

Innovative technology

With a carefully selected and unique combination of biology and internet of things technology, a CityTree is a powerful biofilter for the environment. Each tree has integrated sensors that can upload data wirelessly to a system, keeping the producers informed on the health of the tree and the pollution levels in the surrounding air. After being analysed against other CityTrees, this data is used to keep the trees healthy and performing optimally.

Making a difference

Just like CityTrees are working to combat air pollution, we can all make small changes to help to keep our air clean. Whether that’s cycling to work once a week or reducing the amount of meat we eat, everything can help to protect our planet. In our next post, we look at Kaalink, a product that converts pollution into printer ink.

Want to know more about technology to turn waste into something useful? Take a look at the article ‘Blue Mountain Biogas Plant Turns Pig Manure into Power’.


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