The war against air pollution will be won or lost in the world’s cities. As greater numbers of people move to urban areas, it’s clear that unless more is done to tackle pollution, insurmountable strains will be put on health systems and other essential infrastructure.
At present, over three million people around the world die prematurely because of urban air pollution. It causes heart attacks, strokes, lung disease, and may be a contributing factor to brain disorders such as Alzheimer’s. It also affects the most vulnerable, like children, with numbers suffering from asthma on the rise, while reports indicate it impairs their physical and mental development.
But the situation is beginning to change. New, low carbon transport systems in cities and the increasing use of electric vehicles on the roads are already making an impact. Meanwhile, architects, designers and engineers are turning their attention to tackling pollution in urban environments, and finding ingenious ways to make the air we breathe cleaner.
In 2014, Milan’s central business district became the home to a remarkable new structure. Called the Bosco Verticale (Vertical Forest) it consists of two high-rise buildings whose exteriors ripple with organic life. The brainchild of architect Stefano Boeri, these buildings feature balconies that support 730 specially cultivated trees, 11,000 plants and 5,000 shrubs. Their task is to absorb dust in the air and create a microclimate that produces oxygen and absorbs CO2. They also look breath-taking, bringing nature right into the heart of the city.
The Bosco Verticale has proved to be a game-changer, with Boeri now taking his concept of biological architecture to China, a country blighted with some of the worst urban pollution in the world. In Nanjing, two further towers are under construction and will feature 23 species of tree and more than 2,500 cascading shrubs. They are estimated to suck in 25 tons of carbon dioxide a year and produce about 60kg of oxygen every day.
Boeri has been coming to China for over 30 years, and now has an office in Shanghai, where even more ambitious plans are afoot to create ‘forest cities’, the first being in Liuzhou, a city of about 1.5 million people. “By 2020 we could have the first forest city in China,” he says. Such forest cities could in turn provide a greener way forward for urban environments all over the world.
In tune with the environment
This idea of living buildings is taking off elsewhere too. Plans for a ‘smog-eating music school’ in Krakow, Poland, are well under way. Polish studio FAAB aims to cover the roof of the proposed building with a specially grown moss that’s able to absorb pollutants like nitrous oxide and ozone. The product has been developed by German firm, Green City Solutions, and their CEO Dénes Honus claims it “literally eats air pollution”.
Applied to around 1,300sqm of the school’s external surface, it’s claimed to be the equivalent of planting over 30,000 trees. Green City Solutions also utilise the same organic substance to make what they call the CityTree. It’s a four metre high freestanding installation, small and mobile enough call be placed in all kinds of city locations, and represents the equivalent of up to 275 trees, in turn reducing pollution by 30 per cent within a 50-metre radius.
Another freestanding structure that we might be seeing in cities sometime soon is the Smog Free Tower. Made by Dutch designer Dan Roosegaarde, it looks like something you’d expect to see aliens emerge from in an episode of Doctor Who. It’s actually a giant version of the air purifiers you find in people’s homes. Standing at seven metres in height, it sucks in polluted air through the top and releases purified air through its vents in the sides. Piloted in Rotterdam, it has since made its way to Beijing, where Roosegaarde has plans to scale it up in a bid to make China’s capital city entirely smog free.
A more counter-intuitive idea for tackling urban pollution is the use of concrete. Except we’re not talking about any old concrete – instead it’s concrete that contains what’s called a photocatalyst.
Photocatalysts accelerate the chemical reaction where sunlight decomposes organic materials, biological organisms and airborne pollutants, breaking it down into little more than oxygen and water. When mixed into concrete, it can be used to build self-cleaning structures that also absorb and neutralise chemicals like nitrogen oxide and sulphuric oxide.
It is already being used in the Richard Meier-designed Jubilee Church in Rome and in paving stones in Tokyo, while Spanish architects, BCQ, have plans to use it on the Sarajevo Bridge in Barcelona. This material could also be used in the future construction of roads, making it the first line of defence in the war on pollution.