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Take a deep breath…but wait—maybe not too deep. According to the World Health Organization, 99% of the worldwide population (and 96% in Europe) breathe air that exceeds the WHO guideline limits and contains high levels of pollutants. It doesn’t end there—air quality is closely linked to the earth’s climate and ecosystems globally, and many of the drivers of air pollution (i.e. combustion of fossil fuels) are also sources of greenhouse gas emissions.
Mosses are one of the oldest land plants on earth, dating back 450 million years.
This is where a very humble plant comes in to play the role of climate superhero: our Berlin/Brandenburg-based greentech company, Green City Solutions, is harnessing the power of natural moss plants by combining them with cutting-edge Internet-of-Things (IoT) technology to combat air pollution and cool heat islands in urban areas. But before explaining this surprising approach in detail, it makes sense to take a closer look at the secret superhero that is moss.
Mosses are one of the oldest land plants on earth, dating back 450 million years. They have no roots in the conventional sense and therefore have to absorb everything they need to live and grow via their leaf surface. And this surface is particularly large due to their many fine leaves.
These special properties make mosses an important ally in the fight against air pollution and global warming because they feed on airborne pollutants. Some mosses use the ammonia from vehicle emissions as a nutrient; others bind and metabolise fine dust. In addition, all mosses are small sponges: since they also draw water from the air, they do well to absorb and store a lot of moisture if the humidity is high. Via this evaporation, a considerable cooling of the air occurs.
Mosses are tough plants and can survive drought and other harsh conditions. But to realise their full potential to clean and cool air in the most efficient way—and in the unfriendly living conditions of urban spaces—we needed several years of research and development to perfect our moss-filters. By combining an active filter system with vertical moss mats and intelligent technology, and supplying them with their own bio-algorithm, we not only made the mosses viable in the cities but also measurably improved quality of and cooled the surrounding air. The polluted, heated air gets actively sucked into and pushed through the filtering moss mats.
According to tests with independent institutions, such as the TROPOS Institute for Tropospheric Research in Leipzig or the Institute for Air and Refrigeration Technology in Dresden (ILK), the active biofilters are able to clean up to 82% of fine dust from the air and cool the air by up to 4°C via evaporation.
At Green City Solutions we also love trees, and would like to see a lot more of them in cities around the globe. But the reality is that a lot of the space in cities simply does not allow for them.
And that’s not all. Since space in cities is limited, the moss filters from Green City Solutions have been equipped with smart additional benefits: they serve, for example, as a seating area in a fresh air zone or integrate free WiFi.
Photo: Cork City Council
Equipped with a large LCD screen, the moss filters can be used as a digital advertising or information medium in the streets, on large buildings, during events or in shopping malls. To clean the air at a large scale, a free-standing wall element has also been developed.
But why do we not simply plant more trees in cities? This is a question that pops up regularly. At Green City Solutions we also love trees, and would like to see a lot more of them in cities around the globe. But the reality is that a lot of the space in cities simply does not allow for trees to grow and become valuable providers of shade and fresh air. They also need years to grow and need constant care. Here is where the moss filters can help: to bridge the time until new trees have matured, or to provide fresh air where there is no space underground for a tree to grow its roots.
In addition to the air-purifying and cooling effects, the mosses—and especially the active moss filters—are also good for the climate. Mosses bind CO2 and convert it into oxygen via photosynthesis. However, there are numerous other gases and substances that harm the climate. One of these is soot ("black carbon"), which has a global warming effect that is up to 1,500 times greater than that of CO2. Mosses filter such soot particles, which are present in the air as fine dust. For example, a CityTree moss filter offsets up to 355kg of CO2 and CO2 equivalents per year, making it an effective climate protection measure.
The solution to creating sustainable cities is clear, but what is missing is the risk affinity and open-mindedness to implement it.
Cities like London, Cork and Brunswick and have already set up the moss filters as part of a total number of 59 projects in Europe to date. But the decision-making paths are long—especially in the public sector—and cities and municipalities in particular are hesitant when it comes to using new and innovative technologies. Yet action is so urgently needed with regard to climate adaptation and air pollution control. Therefore, we strongly rely on the private sector and the real estate industry, which are under pressure to use sustainable and climate-friendly technologies.
The European Green Deal and the new WHO recommendations on air quality provide a clear vision for sustainable urban development. However, in order for cities to remain liveable and sustainable for future generations, decision-makers must have the confidence to implement these projects consistently. The solution to creating sustainable cities is clear, but what is missing is the risk affinity and open-mindedness to implement it. Investing in clean energy and public transportation, promoting sustainable building practices, and encouraging green spaces and nature-based solutions can create jobs, improve air quality and enhance the overall well-being of citizens. It is important to remember that the long-term benefits of sustainability far outweigh the short-term costs.
More on the Forum Network: Carbon Dioxide Removal: The Reversible and the Irreversible by Henry Shue, Senior Research Fellow, Centre for International Studies, Merton College, University of Oxford