Many cities around the world are struggling with the air quality, but luckily many people are involved in tackling this problem. Some suggest using fancy technologies whereas others propose returning to roots. Chances are in order to truly make a dent in the quality of the air in cities we will have to combine different technologies and techniques. Here are a few things cities could do in order to help citizens get a breath of fresh air…
These smart green walls can clean urban air
German company Green City Solutions developed CityTree, an innovative solution that combines the natural abilities of mosses with intelligent IoT technology. The cost-effective, low-maintenance and flexibly implementable biofilter aims to significantly improve the quality of life in cities.
The CityTree consists of a bench, a green wall, tools to measure the performance and environmental data, solar panels and a battery to power the automatic irrigation system. The air filters have the capacity equivalent to as many as seven thousand people to breathe freely, according to Green City Solutions.
A tufting plant called biting stonecrop or wallpepper, sedum acre, is used for the protective layer on the moss; the green wall can bind more than 80% of the fine dust in certain cases, according to some of the measurements.
The manufacturers claim one CityTree is equivalent to 275 trees. The calculations revealed the air filters take out a maximum of 240 tons of carbon dioxide per annum, but that they also save citizens from nitrogen dioxide.
A curved roadside barrier that can mitigate air pollution
The health concerns arising from lower air quality are more significant amongst lower-income communities which are more likely to be situated near heavily traffic-laden thoroughfares. Similarly, children are both more vulnerable to and more readily exposed to air pollution simply due to their proximity to the ground, where heavier pollutants settle over time.
Dr Tilly Collins, from Imperial College London’s Centre for Environmental Policy, found this issue particularly worrying, especially after noticing the severe pollution in the air while watching her child playing netball in a school playground alongside a busy London A-road.
And so she — alongside Dr Huw Woodward, also from the Centre for Environmental Policy, and Agamemnon Otero of Energy Garden — started researching the effect of walls along roads.
The result of their research, published in the journal Cities & Health, is a curved structure that could more effectively disperse and reflect pollutants back towards the roads and would very rapidly improve air quality for pedestrians in an inexpensive manner. The design is said to be inspired by airfield baffles and the curved sound walls alongside motorways in Germany and the Netherlands.
Beyond air quality, these curved barriers would also mitigate noise pollution and would be able to act as scaffolds to increase green infrastructure throughout large cities.
A bicycle wheel that can filter outdoor air pollution
We already know that cycling is much better for air quality than driving a car. But imagine a bicycle that would not only be carbon neutral but could also purify the air around us!
Kristen Tapping, a design student at London South Bank University, has designed GoRolloe, a bicycle wheel with pollution filters that uses movement to purify the air.
GoRolloe does not require additional energy to operate as it uses the kinetic energy of moving vehicles. Compared to other outdoor air purification devices, it captures polluted air directly at the source, allowing for greater efficiency and impact.
The device has three parts – a tri-wheel and two circles that hold together washable and circular air filters. As the bicycle wheel rotates, GoRolloe recreates a centrifugal fan that sucks polluted air into the center of the taurus, passes it through a set of filters, and expels cleaner air into the environment.
But wait, there’s more! Instead of relying on single-use filters, those GoRolloe uses can be cleaned and reused. Heck, even the captured pollutants can be reused for third-party products such as construction materials.
This modular smog tower filters air without any outsourced power
Students at Howest University in Belgium had an idea how to tackle smog and they unveiled Airpal – a sustainable, modular smog tower that improves biodiversity and purifies the air, without any external energy source required.
Mehdi Zekri, Gregory Van der Donckt and Mohamed Hmeid, who developed the concept, were studying sustainable cities and communities. “After analyzing polluted locations in a city and the way we can solve air pollution and biodiversity, we ended up at a smog tower. Then we inspired ourselves on the air purifier in a Chinese city called Xi’an and the smog tower in Delhi,” the students said.
The design consists of simple white concrete and only three basic parts: the cubicle, the foundation part, and the filter. In that sense, Airpal is easy to assemble – with cubicles stacked on top of each other and filters installed in place. Municipalities can assemble the design in different sizes according to their wishes, thanks to the modularity of the pieces.
The tower is made out of white concrete to keep the chimney cool, but the foundation and filters are of a dark color to absorb as much heat to enhance the draft effect. Smog emerges as a thick heavy warm layer, creating a higher pressure at the bottom. The cold air higher and the wind create a lower pressure and thus create a draft that sucks the smog into the filters.
For the installation, one only has to dig a pit, fill it and tamp down once the foundation is in place. The flexibility of the design also means that it can be moved over time and does not even have to be dismantled during work.
These tiny urban forests could boost cities’ biodiversity, help fight climate change
When we think of forests, we usually imagine a bunch of trees spread across a big chunk of land. But, there is also an alternative that comes in the form of urban forests that can thrive on space as big (or that’s as small) as a tennis court.
And unsurprisingly such projects have started springing up on patches of land in urban areas around the world, often planted by local community groups using a method inspired by Japanese temples.
The main idea is to use a variety of native seedlings and plant them densely, from where nature will do it all by itself with little to no human intervention.
This method is based on the work of Japanese botanist Akira Miyawaki; he found that protected areas around temples, shrines and cemeteries in Japan contained a huge variety of native vegetation that co-existed to produce resilient and diverse ecosystems. This was in sharp contrast to the conifer forests, where non-indigenous trees are grown for timber. What’s more, these native forests act as oases for biodiversity, supporting up to 20 times as many species as non-native, managed forests.
Miyawaki’s work, now known as the Miyawaki method, presumes prioritizing the natural development of forests using native species. Miyawaki forests can grow into mature ecosystems in just 20 years, which is super fast considering that it takes 200 years for a forest to regenerate on its own.
These native forests also get to benefit from local pollinators such as butterflies and bees, beetles, snails and amphibians — all of which thrive with a greater diversity of food and shelter.
Beyond biodiversity, these small forests are said to improve people’s mental health, reduce the harmful effects of air pollution, and even counter the phenomenon of heat islands in cities.
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