What is the smog tower installed to rid Delhiites of poisonous air?

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The Delhi government has resorted to a technical solution to protect the people of the country’s capital, Delhi, from poisonous air.

The government has set up a smog tower behind Shivaji Stadium metro station for the same. Chief Minister Arvind Kejriwal also inaugurated it on Monday. The tower is said to help clean up the contaminated air.

Delhi reaches a very poor level AQI

Delhi’s air is poisoned due to other reasons including stubble burnt in neighbouring states in winter.

The situation is that in November last year, the Air Quality Index (AQI) had crossed 450. It was also making it difficult for people to breathe.

The Supreme Court had also asked the Delhi government to take necessary steps to remedy it. Work on the smog tower had started since then.

Supreme Court directs planning of smog tower

In view of the rising smog in Delhi, the Supreme Court had constituted a high-level committee in 2019. The committee had suggested the installation of smog towers after studying the situation in Delhi.

The court had then directed the Central Pollution Control Board (CPCB) and the Delhi government to plan to install smog towers.

The IIT-Bombay had then submitted a proposal for the towers. Which was approved in January 2020.

Initially orders were given to install towers at two places

On January 13, the Supreme Court had ordered the Central Pollution Control Board to install smog towers at Connaught Place and Anand Vihar in Delhi within three months.

On February 28, another order asked the agency to start work and report it to the court within a week. Nevertheless, no work has been done in this direction.

The agency had then sought 10 months’ time. Which was accepted by the Supreme Court.

What happens to the smog tower?

In simple terms, the smog tower is a large size air purifier. It pulls in the contaminated air around. Absorbs dirt from the air and throws clean air out.

Overall it is like a large-scale air cleaning machine. It can clean several cubic meters of air in an hour.

Similarly, purifying air by cleaning harmful particles like PM2.5 and PM10 up to 75 percent.

What is the structure of the smog tower installed in Delhi?

According to sources, the smog tower is a structure equal to 24 metres, or eight floors, with a concrete tower of 18 metres in height, while a six-metre canopy is on top.

It has 10-10 fans around its base. Each fan cleans 25 cubic meters of air every second, i.e. 1,000 cubic meters of air in a second.

There are a total of 5,000 filters in two layers inside the tower. Filters and fans are imported from the US.

This technique has been used in smog towers

A senior engineer in charge of the Smog Tower Project and a senior engineer of the Delhi Pollution Control Committee said the tower uses a downdraft air cleaning system developed by the University of Minnesota.

experts from IIT Bombay have worked closely with the University of Minnesota in the US to use the technology in India.

The commercial unit of Tata Projects Limited has since materialized the project. This technology can prove to be a boon for Delhi.

How does smog tower clean the air?

Under this technology, polluted air enters the tower from a height of 24 metres and the cleaned air is released from a tower built 10 metres above the ground. When the wings at the bottom of the tower are run, the air comes in from the top of the tower due to negative pressure.

The macro layer applied to the filter cleans up to 10 microns and the micro layer contains contaminated particles up to 0.3 microns.

Study to be conducted on the success of smog tower

Computational fluid dynamics modelling by IIT Bombay shows that smog tower can affect the air quality of its area up to 1 km.

The impact will be assessed by IIT Bombay and IIT Delhi for two years.

It will also determine how the tower works in different weather conditions, and how the level of PM 2.5 changes with the flow of air.