Smog towers or smog free towers (see below for other names) are structures designed as large-scale air purifiers to reduce air pollution particles (smog). This approach to the problem of urban air pollution involves air filtration, and removal of suspended mechanical particulates such as soot, and requires energy or power. Another approach is to remove urban air pollution by a chimney effect in a tall stack, or updraft tower, which may be either filtered or simply released at altitude as with a solar updraft tower, and which may not require operating energy beyond what may be produced by the updraft.
World’s first air cleaning tower
The world's first smog free tower was built by Dutch artist Daan Roosegaarde. It was unveiled in September 2015 in Rotterdam[1] and later similar structures toured in[2]Beijing and Tianjin, China, Kraków, Poland[3] and Anyang, South Korea.[4] The 7-meter (23 ft) tall tower uses patented positive ionisation technology and is expected to clean 30,000 m3 of air per hour.[2]
Gallery
Rotterdam
Beijing 1
Beijing 2
Beijing 3
Beijing 4
Beijing 5
Beijing 6
Beijing 7
World’s largest air cleaning tower
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First generation SALSCS, Xi'an
In 2016,[5][6] a 100-metre (330 ft) tower has been built in Xi'an, Shaanxi to tackle the city's pollution.[7] It was funded by the provincial government and costs US$2 million. The running cost is $30000 per year.[8] It is under testing by researchers at the Institute of Earth Environment of the Chinese Academy of Sciences.[9]
The experimental demonstration urban updraft tower is cleaning the air in central China with little external energy input.[10][11] A 60-metre urban chimney is surrounded by solar collector. This project was led by Cao Jun Ji, a chemist at the Chinese Academy of Sciences' Key Laboratory of Aerosol Chemistry and Physics.[8] This work has since been published on, with the performance data and modelling.[12][13]
Other towers
India
As of 2022[update], there are at least eight smog towers in India, some of which are smaller in scale:
In Delhi, India Kurin Systems is developing a 12-metre (40 ft) tall smog tower, called the "Kurin City Cleaner".[24] It is different from Daan Roosegaarde's Smog Tower in that it won't depend on the ionization technique to clean the air. The H14 grade HEPA Filter, known for being able to clean up to 99.99% of the particulate matter, will be used instead, together with a pre-filter and activated carbon.[25] It is claimed the tower will filter air for up to 75,000 people within a 3-kilometre (1.9 mi) radius.[26] and cleaning more than 32 million cubic metres of air every day.[27]
Reception
Some air pollution experts view smog filtration tower projects with scepticism. For example, Alastair Lewis, Professor of Atmospheric Chemistry at the University of York, Science Director at the National Centre for Atmospheric Science, and chair of the Air Quality Expert Group, has argued that static air cleaners, like the prototypes in Beijing and Delhi, cannot process enough city air, quickly enough, to make a meaningful difference to urban pollution. Instead, Lewis argues that "it is far, far easier to come up with technologies and schemes that stop harmful emissions at source, rather than to try to capture the resulting pollution once it's free and in the air".[28] Noting that the Delhi tower would be powered by (mostly) coal-fired electricity, Sunil Dahiya from India's Centre for Research on Energy and Clean Air has commented that "so we will only be adding to pollution elsewhere in the country".[29] According to The Times, environmentalists "decried" the Delhi project on the grounds that "given the city's size and the scale of its pollution, 2.5 million smog towers would be needed to clean its air".[30] As a refute, "The objective is not to clear entire Delhi's air, it is to create special zones where people can breathe," Anwar Ali Khan, the engineer in charge of the project said.[29]
