Wikipedia

Smog tower

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 released at altitude as with a solar updraft tower and which may not require operating energy beyond what may be produced by the updraft.

Smog free tower in Beijing

World’s first air cleaning tower

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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 or were installed in[2] Beijing and Tianjin, China, Kraków, Poland[3], Anyang, South Korea[4] and Abu Dhabi.[5] 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]

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    Rotterdam
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    Beijing 1
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    Beijing 2
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    Beijing 3
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    Beijing 4
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    Beijing 5
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    Beijing 6
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    Beijing 7

World’s largest air cleaning tower

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First generation SALSCS, Xi'an

In 2016,[6][7] a 100-metre (330 ft) tower has been built in Xi'an, Shaanxi to tackle the city's pollution.[8] It was funded by the provincial government and costs US$2 million. The running cost is $30000 per year.[9] It is under testing by researchers at the Institute of Earth Environment of the Chinese Academy of Sciences.[10]

The experimental demonstration urban updraft tower is cleaning the air in central China with little external energy input.[11][12] 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.[9] This work has since been published on, with the performance data and modelling.[13][14]

"I like to tell my students that we don’t need to be medical doctors to save lives ... If we can just reduce the air pollution in major metropolitan areas by 20 percent, for example, we can save tens of thousands of lives each year ... I hope that people will realize that this is a really effective and cheap way to solve the PM2.5 problem." [6]

“In the case of India, their population is more packed together, so the towers will be more effective in mitigating PM2.5 … At least during the next 10-15 years, they can use them to provide relief to residents while they invest in clean energy technology.”[15]

—David Pui, Regents Professor and LM Fingerson/TSI Chair in Mechanical Engineering of the University of Minnesota, explained.[15]

Other towers

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India

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As of 2022, there are at least eight smog towers in India, some of which are smaller in scale:

Projects under development

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In Delhi, India Kurin Systems is developing a 12-metre (40 ft) tall smog tower, called the "Kurin City Cleaner".[26] 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.[27] It is claimed the tower will filter air for up to 75,000 people within a 3-kilometre (1.9 mi) radius.[28] and cleaning more than 32 million cubic metres of air every day.[29] ZNera Space proposed Lutyens' Delhi smog tower network.[30]

Efficacy

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In 2023, some researchers from IIT Bombay conducted a study on the smog tower in Connaught Place, Delhi. They found that the tower's air cleaning efficiency varies with distance. At the source, it operates at 50% efficiency, but this drops to 30% just 50 meters away, and further decreases to slightly over 10% at a distance of 500 meters. They also found that the filter housing was not properly sealed, allowing contaminated air to circumvent the filtration process.[31]

Reception

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There are air pollution experts who view smog filtration tower projects with scepticism. For example, Professor Alastair Lewis, Science Director at the NCAS, 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. He said that it was "easier[unbalanced opinion?] 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".[32]

Noting that the Delhi tower would be powered by (mostly) coal-fired electricity,[dubious – discuss] 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".[33] According to The Times, environmentalists said that "given the city[Delhi]'s size and the scale of its pollution, 2.5 million smog towers would be needed to clean its air".[34] 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.[33]

See also

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References

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  1. ^ "Ingenious 'Smog Free Tower' unveiled in Rotterdam". European Commission. Archived from the original on 2022-02-01.
  2. ^ a b "SMOG FREE TOWER". 17 October 2019.
  3. ^ Bürklein, Christiane (2018-02-27). "Smog Free Tower by Daan Roosegaarde in Krakow Poland". Floornature.com (in Italian). Retrieved 2019-01-05.
  4. ^ "South Korea's Smog Free Tower turns air pollutants into jewellery". 18 October 2019.
  5. ^ "First Smog-Free Tower". EAD. 8 Feb 2024. Retrieved 18 Nov 2024.
  6. ^ a b "This skyscraper-sized air purifier is the world's tallest". NBC News. 21 March 2018.
  7. ^ "了解"网红"除霾塔----中国科学院西安分院".
  8. ^ Smith, Rob (February 19, 2018). "China has built the 'world's largest air purifier' to battle smog". World Economic Forum. Retrieved 2023-01-02.
  9. ^ a b Cyranoski, David (2018). "China tests giant air cleaner to combat smog" (PDF). Nature. 555 (7695). Springer Science and Business Media LLC: 152–153. Bibcode:2018Natur.555..152C. doi:10.1038/d41586-018-02704-9. ISSN 0028-0836.
  10. ^ Post, South China Morning. "China built a tower that acts like the world's biggest air purifier, and it actually works". Business Insider. Retrieved 2019-01-05.
  11. ^ Chen, Stephen (16 Jan 2018). "China builds 'world's biggest air purifier' – and it works". South China Morning Post. Archived from the original on 15 Jan 2018. Retrieved 24 Feb 2024.{{cite web}}: CS1 maint: unfit URL (link)
  12. ^ Hanly, Ken (7 Mar 2018). "China tests giant chimney to combat air pollution". Digital Journal. Retrieved 24 Feb 2024.
  13. ^ Cao, Qingfeng; Kuehn, Thomas H.; Shen, Lian; Chen, Sheng-Chieh; Zhang, Ningning; Huang, Yu; Cao, Junji; Pui, David Y.H. (2018). "Urban-scale SALSCS, Part I: Experimental Evaluation and Numerical Modeling of a Demonstration Unit" (PDF). Aerosol and Air Quality Research. 18 (11). Taiwan Association for Aerosol Research: 2865–2878. doi:10.4209/aaqr.2018.06.0238. ISSN 1680-8584.
  14. ^ Cao, Qingfeng; Huang, Minghua; Kuehn, Thomas H.; Shen, Lian; Tao, Wen-Quan; Cao, Junji; Pui, David Y.H. (2018). "Urban-scale SALSCS, Part II: A Parametric Study of System Performance" (PDF). Aerosol and Air Quality Research. 18 (11). Taiwan Association for Aerosol Research: 2879–2894. doi:10.4209/aaqr.2018.06.0239. ISSN 1680-8584.
  15. ^ a b "Curbing air pollution with purification towers". College of Science and Engineering. 30 Apr 2020. Retrieved 9 May 2024.
  16. ^ "Delhi's pollution fight: All you need to know about country's first smog tower". The Times of India. 24 August 2021.
  17. ^ "How effective is the smog tower at Delhi's Connaught Place?". 2 October 2022.
  18. ^ "Explained, Delhi new smog tower the technology, the evidence, the impact". 25 August 2021.
  19. ^ "Delhi gets first smog tower to combat air pollution". 2 January 2020.
  20. ^ "Delhi gets first smog tower today: 5 things about the air purifier at Lajpat Nagar". 3 January 2020.
  21. ^ "Smog towers: After Supreme Court barb, more air purifiers in the Delhi pipeline". 26 November 2020.
  22. ^ "Gautam Gambhir installs 3 giant air purifiers in Delhi, but experts call it 'unscientific'". 24 November 2020.
  23. ^ "IISc-built smog towers to purify air at 15 traffic choke points". 24 March 2021.
  24. ^ "Chandigarh gets country's tallest air purifier".
  25. ^ "Chandigarh to get country's tallest outdoor air purifier". 20 January 2021.
  26. ^ "Delhi air pollution: India's own 'smog tower' may help combat air pollution | Delhi News - Times of India". The Times of India. 2018-11-05. Retrieved 2019-11-18.
  27. ^ "Gurugram Based Start-Up Develops City-Level Air Purifier To Clean The National Capital's Air". 18 December 2018.
  28. ^ "Made-in-India Smog Tower Spells Hope For Delhi, Can Clean 130 Crore Litres of Air Per Day!". The Better India. 2018-11-05. Retrieved 2019-01-05.
  29. ^ "This Made-in-India smog tower, dubbed 'world's largest', could save Delhi". Business Standard India. Press Trust of India. 2018-11-04. Retrieved 2019-11-18.
  30. ^ "https://znera.space/project/smog-tower/". Retrieved 2024-07-31. {{cite web}}: External link in |title= (help)
  31. ^ Bello, Lou Del (2023-11-12). "What is a smog tower and do they work? How India is fighting air pollution". The Economic Times. ISSN 0013-0389. Retrieved 2024-11-07.
  32. ^ Lewis, Alastair (25 January 2018). "Beware China's 'anti-smog tower' and other plans to pull pollution from the air". The Conversation. Retrieved 14 August 2022.
  33. ^ a b "Smog tower to help Delhi breathe but experts sceptical". France24. 22 July 2021. Retrieved 14 August 2022.
  34. ^ Dhillon, Amrit (24 August 2021). "Delhi unveils 'smog tower' to clean its filthy air". The Times. Retrieved 14 August 2022.

Further reading

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