Air pollution and Architecture (Smog-eating façades)

Air pollution and Architecture (Smog-eating façades)


London breached its legal limits for toxic air for the entire year in the first five days of 2017. Readings showed that air at locations in the capital were worse than the notoriously smoggy Beijing, hitting a peak 197 micrograms per cubic metre for particulate matter on the Air Quality Index. In response to the emergency, Mayor Sadiq Khan issued the highest air pollution alert in London for the first time, stating that the capital’s ‘filthy air’ is now a ‘health crisis.’

The World Health Organisation’s most recent estimate attributes one in eight premature deaths around the world to air pollution. This finding more than doubles previous estimates and confirms that air pollution is now the world’s largest single environmental health risk. Reducing air pollution could save millions of lives. To translate this in local terms: a 2015 study by experts from King’s College London found air pollution in London linked to 9,400 premature deaths a year.

Immediate action is needed. While politicians appear slow to implement change, designers around the world are calling for action to curb dangerous pollution in the city. According to Greenpeace, diesel vehicles are the “single biggest source” of London’s air pollution, however the form and make up of the built environment can greatly affect the city’s capacity to deal with it. Stagnant streetscapes can trap polluted air rather than dissipating it; hard concrete surfaces and a lack of greenery make cities hotter, the elevated temperatures worsening pollution at ground level. Acknowledging the impact of building form and materiality on air pollution, architects and designers are using their unique opportunity to re-imagine buildings as active solutions to combating poor air quality. Proposing both visions and working solutions, architects and designers are stepping up to increase awareness of the issue and show that it is possible to make positive change.

One idea being promoted by engineering firm, Arup, is to encourage cities to adopt strategic plans to ‘green’ the urban realm in order to cut air pollution and dampen noise. The firm says that green building envelopes, such as green walls or green roofs, are reducing street level air pollution by 20% and muffling traffic noise by up to 10 decibels in certain situations. Arup is calling on developers and planners to implement strategic approaches towards ‘greening’ and to harness the benefits of nature to help create a cleaner and healthier environment for all.

Trees and other green plants improve urban air quality by removing CO2 and common urban pollutants like nitrogen dioxide (NO2) and disease-causing particulate matter (PM).  Not only this, research has shown that ‘green infrastructure’ can help to reduce the urban heat island effect, filter fine dust on the streets and soak up storm water surges. Tom Armour, Global Landscape Architecture Leader at Arup said: “Tackling rising air pollution is a priority to help improve people’s health. As our cities continue to become built up, ‘grey’ structures, such as walls and roofs, are a source of untapped potential for adapting into green spaces. Well-designed green envelopes can have a positive impact on tackling air pollution, but can also deliver a wide range of social, economic and environmental benefits to make cities more attractive and healthier places to be.” Research on the health and economic benefits of air cleansing has shown that trees save lives, reduce hospital visits and even reduce the number of days taken off work.

Many architects around the world are also adopting this philosophy; acknowledging the value of nature to improve the environment of our cities. Stefano Boeri is one such architect. His Bosco Verticale (Vertical Forest), a pair of residential towers in Milan, has been built with façades covered by a thick green canopy of trees. The trees sit on the individual terraces of each apartment, cooling the interiors by shading them from direct sunlight. More than 2.5 acres of forest – comprising roughly 800 trees, 11,000 ground-cover plants, and 5,000 shrubs – have been planted on the 111m and 76m towers. These green towers will help to dramatically decrease the city’s C02 emissions and problems with dust.

Nature is a great solution but it is not the only one. Many designers are also developing façade systems that can actively reduce pollutants artificially. A Berlin-based firm, Elegant Embellishments, have developed a pollution-eating façade, the Prosolve370e, a decorative architectural tile that helps reduce air pollution in cities when applied to a building facade. Coated with a superfine titanium dioxide (TiO2), a pollution-fighting technology that is activated by ambient daylight, the tiles neutralise air pollutants when sited near traffic or other polluted conditions. The façade system is a decorative modular design. Inspired by fractals in nature, the undulating shapes maximise the surface area of active coating to diffuse light, air turbulence and pollution. So far, the Prosolve370e is one of the few technologies developed to retrofit existing structures to reduce air pollution.

Another idea by artist and innovator Daan Roosegaarde, proposes giant street side filters to help combat smog in Beijing. The prototype 7m ‘Smog Free Tower’ sucks up polluted air and filters out smog particles before releasing clean air back into the environment. While operating, the Smog Free Tower creates a small bubble of fresh air around itself, allowing inhabitants of the city to experience (perhaps for the first time) the difference between the typical, daily urban air quality and clean smog-free air. China’s Ministry of Environmental Protection recently announced that the air around the tower is in fact 55% cleaner than it was before (however there is some debate over just how accurate the statistic is). According to Studio Roosegaarde, the tower has snatched billions of PM2.5 fine particles out of the polluted air.

While the cost and scope of the Smog Free Tower is somewhat prohibitive, the proposal succeeds in its mission to raise awareness of China’s dirty skies, and the human right for clean air. As part of the Smog Free Project, jewellery made from collected smog particles (rings and cufflinks) are given to visitors as a memento, serving as a lasting reminder of the issues of air quality in their city.

There is no doubt that policy will be the key driver of change in cities, however it is clear that architecture,  the fabric of our cities, can also play an important role in improving air quality, and consequently the quality of life for city dwellers. It’s time for London to clean up its air. Mayor Sadiq Khan has said he’ll double funding; spending £875 million over five years to combat the issue. Rather than sit back and hope that the money is well spent, we should all  demand it.


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