Smog tower

File:Smog free tower in Beijing 03.jpg

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.

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{{cite web | title=Ingenious 'Smog Free Tower' unveiled in Rotterdam | website=European Commission | url=https://ec.europa.eu/environment/europeangreencapital/smog-free-tower-rotterdam/ | archive-url=https://web.archive.org/web/20220201140411/https://ec.europa.eu/environment/europeangreencapital/smog-free-tower-rotterdam/ |archive-date=2022-02-01}} and later similar structures toured or were installed in{{Cite web|url=https://www.studioroosegaarde.net/project/smog-free-tower | title=SMOG FREE TOWER| date=17 October 2019}}

Beijing and Tianjin, China, Kraków, Poland,{{Cite web|url=https://www.floornature.com/blog/smog-free-tower-di-daan-roosegaarde-cracovia-polonia-13563/|title=Smog Free Tower by Daan Roosegaarde in Krakow Poland|last=Bürklein|first=Christiane|date=2018-02-27|website=Floornature.com|language=it|access-date=2019-01-05}} Anyang, South Korea{{Cite web | url=https://airqualitynews.com/2019/10/18/south-koreas-smog-free-tower-turns-air-pollutants-into-jewellery/ | title=South Korea's Smog Free Tower turns air pollutants into jewellery| date=18 October 2019}} and Abu Dhabi.{{cite web | title=First Smog-Free Tower | website=EAD | date=8 Feb 2024 | url=https://www.ead.gov.ae/en/Media-Centre/News/First-Smog-Free-Tower | access-date=18 Nov 2024}} The 7-meter (23 ft) tall tower uses patented positive ionisation technology and is expected to clean 30,000 m3 of air per hour.

=Gallery=

Daan Roosegaarde - Smog Free Tower.JPG|Rotterdam

Smog free tower in Beijing 01.jpg|Beijing 1

Smog free tower in Beijing 04.jpg|Beijing 2

Smog free tower in Beijing 07.jpg|Beijing 3

Smog free tower in Beijing 09.jpg|Beijing 4

Smog free tower in Beijing 13.jpg|Beijing 5

Smog free tower in Beijing 15.jpg|Beijing 6

Smog free tower in Beijing 14.jpg|Beijing 7

World’s largest air cleaning tower

File:First generation SALSCS, Xi'an.jpg

In 2016,{{Cite web | url=https://www.nbcnews.com/mach/science/skyscraper-sized-air-purifier-world-s-tallest-ncna858436 | title=This skyscraper-sized air purifier is the world's tallest| website=NBC News| date=21 March 2018}}{{cite web | url=https://www-xab-cas-cn.translate.goog/cmsj/201901/t20190118_5231380.html?_x_tr_sch=http&_x_tr_sl=zh-CN&_x_tr_tl=en | title=了解"网红"除霾塔----中国科学院西安分院 }} a {{convert|100|m|ft|adj=on}} tower has been built in Xi'an, Shaanxi to tackle the city's pollution.{{Cite web |last=Smith |first=Rob |date=February 19, 2018 |title=China has built the 'world's largest air purifier' to battle smog |url=https://www.weforum.org/agenda/2018/02/china-has-built-the-world-s-largest-air-purifier-to-battle-smog/ |access-date=2023-01-02 |website=World Economic Forum |language=en}} It was funded by the provincial government and costs US$2 million. The running cost is $30000 per year.{{cite journal | last=Cyranoski | first=David | title=China tests giant air cleaner to combat smog | journal=Nature | publisher=Springer Science and Business Media LLC | volume=555 | issue=7695 | year=2018 | issn=0028-0836 | doi=10.1038/d41586-018-02704-9 | url= https://media.nature.com/original/magazine-assets/d41586-018-02704-9/d41586-018-02704-9.pdf | pages=152–153| bibcode=2018Natur.555..152C }} It is under testing by researchers at the Institute of Earth Environment of the Chinese Academy of Sciences.{{Cite web|url=https://www.businessinsider.com/china-builds-worlds-biggest-air-purifier-2018-12|title=China built a tower that acts like the world's biggest air purifier, and it actually works|last=Post|first=South China Morning|website=Business Insider|access-date=2019-01-05}}

The experimental demonstration urban updraft tower is cleaning the air in central China with little external energy input.{{cite web | last=Chen | first=Stephen | title=China builds 'world's biggest air purifier' – and it works | website=South China Morning Post | date=16 Jan 2018 | url=https://www.scmp.com/news/china/society/article/2128355/china-builds-worlds-biggest-air-purifier-and-it-seems-be-working | archive-url=https://web.archive.org/web/20180115232719/https://www.scmp.com/news/china/society/article/2128355/china-builds-worlds-biggest-air-purifier-and-it-seems-be-working | archive-date=15 Jan 2018 | url-status=unfit | access-date=24 Feb 2024}}{{cite web | last=Hanly | first=Ken | title=China tests giant chimney to combat air pollution | website=Digital Journal | date=7 Mar 2018 | url=https://www.digitaljournal.com/tech-science/china-tests-giant-chimney-to-combat-air-pollution/article/516647 | access-date=24 Feb 2024}} 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. This work has since been published on, with the performance data and modelling.{{cite journal | last1=Cao | first1=Qingfeng | last2=Kuehn | first2=Thomas H. | last3=Shen | first3=Lian | last4=Chen | first4=Sheng-Chieh | last5=Zhang | first5=Ningning | last6=Huang | first6=Yu | last7=Cao | first7=Junji | last8=Pui | first8=David Y.H. | title=Urban-scale SALSCS, Part I: Experimental Evaluation and Numerical Modeling of a Demonstration Unit | journal=Aerosol and Air Quality Research | publisher=Taiwan Association for Aerosol Research | volume=18 | issue=11 | year=2018 | issn=1680-8584 | doi=10.4209/aaqr.2018.06.0238 | pages=2865–2878 | url=https://aaqr.org/articles/aaqr-18-06-oa-0238.pdf}}{{cite journal | last1=Cao | first1=Qingfeng | last2=Huang | first2=Minghua | last3=Kuehn | first3=Thomas H. | last4=Shen | first4=Lian | last5=Tao | first5=Wen-Quan | last6=Cao | first6=Junji | last7=Pui | first7=David Y.H. | title=Urban-scale SALSCS, Part II: A Parametric Study of System Performance | journal=Aerosol and Air Quality Research | publisher=Taiwan Association for Aerosol Research | volume=18 | issue=11 | year=2018 | issn=1680-8584 | doi=10.4209/aaqr.2018.06.0239 | pages=2879–2894 | url=https://aaqr.org/articles/aaqr-18-06-oa-0239.pdf}}

"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."

“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.”{{cite web | title=Curbing air pollution with purification towers | website=College of Science and Engineering | date=30 Apr 2020 | url=https://cse.umn.edu/college/news/curbing-air-pollution-purification-towers | access-date=9 May 2024}}

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

Other towers

=India=

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

Connaught Place (around 80 ft; since Aug 2021){{Cite news | url=https://timesofindia.indiatimes.com/city/delhi/40-fans-5k-filters-24m-high-smog-tower-opens-in-cp/articleshow/85573665.cms | title=Delhi's pollution fight: All you need to know about country's first smog tower| website=The Times of India| date=24 August 2021}}{{Cite web | url=

https://indianexpress.com/article/cities/delhi/delhis-smog-tower-ready-to-work-round-the-clock-winter-approaches-8185249/lite/ | title=How effective is the smog tower at Delhi's Connaught Place?| date=2 October 2022}}

Anand Vihar (around 80 ft){{Cite web | url=https://www.jatinverma.org/explained-delhi-new-smog-tower-the-technology-the-evidence-the-impact | title=Explained, Delhi new smog tower the technology, the evidence, the impact| date=25 August 2021}}
Lajpat Nagar Central market{{Cite web | url=https://www.hindustantimes.com/cities/delhi-s-first-smog-tower-to-start-working-at-lajpat-nagar-from-friday/story-iMDG2W04FGK0cxhcYm0SnI.html | title=Delhi gets first smog tower to combat air pollution| date=2 January 2020}}{{Cite web | url=https://www.hindustantimes.com/delhi-news/delhi-gets-1st-smog-tower-today-5-things-about-the-air-purifier-at-lajpat-nagar/story-jjx9ki6YVqmbvi71pJKSZL.html | title=Delhi gets first smog tower today: 5 things about the air purifier at Lajpat Nagar| date=3 January 2020}} (20 ft; since Jan 2020)
Gandhi Nagar market (12 ft){{Cite web | url=https://www.indialegallive.com/cover-story-articles/il-feature-news/environment-smog-towers-delhi-gautam-gambhir-polluted-air/ | title= Smog towers: After Supreme Court barb, more air purifiers in the Delhi pipeline| date= 26 November 2020}}
Krishna Nagar market (12 ft){{Cite web | url=https://theprint.in/environment/gautam-gambhir-installs-3-giant-air-purifiers-in-delhi-but-experts-call-it-unscientific/550732/?amp | title=Gautam Gambhir installs 3 giant air purifiers in Delhi, but experts call it 'unscientific'| date=24 November 2020}}
Bangalore (15 more maybe installed later){{Cite web | url=https://www.deccanherald.com/amp/city/iisc-built-smog-towers-to-purify-air-at-15-traffic-choke-points-965713.html | title=IISc-built smog towers to purify air at 15 traffic choke points| date=24 March 2021}}
Chandigarh (24–25 m; water used to remove pollutants){{Cite web | url=https://tribuneindia.com/news/chandigarh/chandigarh-gets-countrys-tallest-air-purifier-308261 | title=Chandigarh gets country's tallest air purifier}}{{Cite web | url=https://www.hindustantimes.com/cities/chandigarh-news/chandigarh-to-get-country-s-taller-outdoor-air-purifier-101611163398756-amp.html | title=Chandigarh to get country's tallest outdoor air purifier| date=20 January 2021}}
Jaipur{{cn|date=November 2023}}

Projects under development

In Delhi, India Kurin Systems is developing a {{convert|40|ft|m|adj=on|order=flip}} tall smog tower, called the "Kurin City Cleaner".{{Cite web|url=https://timesofindia.indiatimes.com/city/delhi/indias-own-smog-tower-may-help-combat-air-pollution/articleshow/66509232.cms|title=Delhi air pollution: India's own 'smog tower' may help combat air pollution {{!}} Delhi News - Times of India|website=The Times of India|language=en|access-date=2019-11-18|date=2018-11-05}} 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.{{Cite web|url=https://swachhindia.ndtv.com/gurugram-startup-city-air-purifier-ncr-air-pollution-28828/ | title=Gurugram Based Start-Up Develops City-Level Air Purifier To Clean The National Capital's Air| date=18 December 2018}} It is claimed the tower will filter air for up to 75,000 people within a {{convert|3|km|mi|adj=on}} radius.{{Cite web|url=https://www.thebetterindia.com/163770/delhi-air-pollution-solution-kurin-smog-tower-news/|title=Made-in-India Smog Tower Spells Hope For Delhi, Can Clean 130 Crore Litres of Air Per Day!|date=2018-11-05|website=The Better India|language=en-US|access-date=2019-01-05}} and cleaning more than 32 million cubic metres of air every day.{{Cite news|url=https://www.business-standard.com/article/current-affairs/this-made-in-india-smog-tower-dubbed-world-s-largest-could-save-delhi-118110400122_1.html|title=This Made-in-India smog tower, dubbed 'world's largest', could save Delhi|agency=Press Trust of India|date=2018-11-04|work=Business Standard India|access-date=2019-11-18}} ZNera Space proposed Lutyens' Delhi smog tower network.{{Cite web |title=Futuristic Projects: Smog Tower. Location, New Delhi, India |url=https://znera.space/project/smog-tower/ |access-date=2024-07-31 |website=ZNera |language=en}}

Efficacy

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.{{Cite news |last=Bello |first=Lou Del |date=2023-11-12 |title=What is a smog tower and do they work? How India is fighting air pollution |url=https://economictimes.indiatimes.com/news/india/what-is-a-smog-tower-and-do-they-work-how-india-is-fighting-air-pollution/articleshow/105161807.cms |access-date=2024-11-07 |work=The Economic Times |issn=0013-0389}}

Reception

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|date=May 2024}} 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".{{cite web |last1=Lewis |first1=Alastair |title=Beware China's 'anti-smog tower' and other plans to pull pollution from the air |url=https://theconversation.com/beware-chinas-anti-smog-tower-and-other-plans-to-pull-pollution-from-the-air-90596 |website=The Conversation |access-date=14 August 2022 |date=25 January 2018}}

Noting that the Delhi tower would be powered by (mostly) coal-fired electricity,{{dubious inline|date=May 2024}} 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".{{cite news |title=Smog tower to help Delhi breathe but experts sceptical |url=https://www.france24.com/en/live-news/20210722-smog-tower-to-help-delhi-breathe-but-experts-sceptical |access-date=14 August 2022 |work=France24 |date=22 July 2021}} 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".{{cite news |last1=Dhillon |first1=Amrit |title=Delhi unveils 'smog tower' to clean its filthy air |url=https://www.thetimes.com/world/article/delhi-unveils-smog-tower-clean-filthy-air-pollution-qt6ssn2cq |access-date=14 August 2022 |work=The Times |date=24 August 2021}} 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.

References

External links

[https://www.youtube.com/watch?v=ut0qdufPPws&t=2024s "Filtration Solutions to Mitigate Coronavirus Aerosol and PM2.5 Pollutants" by Professor David Pui] David Y. H. Pui talked about the smog free towers (SALSCS) in Xi'an and Delhi (video starts from 33:44)
[https://www-asiatime-co-kr.translate.goog/236477?_x_tr_sl=auto&_x_tr_tl=en IFC Mall installs extra-large air purifiers to manage indoor fine dust] (machine translation, original text in Korean)
[https://www-lafent-com.translate.goog/mtrial/mtr_view.html?idx=16051&mcd=F01&_x_tr_sch=http&_x_tr_sl=ko&_x_tr_tl=en Development of Passive/Active integrated module device for fine dust free zone implementation (2nd year)] | [https://www-sisajournal-com.translate.goog/news/articleView.html?idxno=189777&_x_tr_sl=ko&_x_tr_tl=en Bucheon City, Korea's first fine dust reduction device pilot operation] (machine translation, original text in Korean)
[https://www.nutanlabs.com/smog-tower.php Nutan Labs Smog Towers], Nutan Labs is the producer of the tower in Bangalore
[https://timesofindia.indiatimes.com/city/delhi/this-device-can-purify-air-over-500-sqm/articleshow/65956297.cms This device can purify air over 500 sqm]
[https://www.hindustantimes.com/delhi-news/wayu-air-purifiers-on-delhi-roads-turn-dustbins-spittoons/story-UgltlSAQLebsHMuiBdlNOK.html WAYU air purifiers on Delhi roads turn dustbins, spittoons]
[https://www.dezeen.com/2018/08/30/znera-delhi-smog-air-pollution-filter-towers-architecture/ Vast grid of filter towers proposed across Delhi to combat toxic smog]
[https://www.dezeen.com/2020/01/09/studio-symbiosis-aura-towers-air-pollution-delhi-architecture/amp/ Studio Symbiosis proposes Aũra towers to alleviate air pollution in Delhi]

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Category:Air pollution

Category:Building biology

Category:Energy conversion

Category:Filters