Smog tower

Syllabus– General Studies 3(environment) 

Context

Delhi government inaugurated a ‘smog tower’ in Connaught Place and said similar towers would be built across the city, if results of the current pilot project are satisfactory.

Supreme Court Order

• On January 13 2020, the Supreme Court had ordered the Delhi government to build a ‘smog tower’ at Connaught Place by April 13, 2020, to control air pollution. 
• On the same day, the court also ordered a smog tower to be installed in Anand Vihar by the Central Pollution Control Board, by the same time.
• But both the governments missed the deadline.
• On July 29, 2020, the Supreme Court threatened contempt action against the IIT-Bombay on learning that the premier institution has opted to pull out of the court-ordered project to install the smog tower.

About the Smog tower

• It will draw in polluted air from the top and release filtered air near the ground through fans fitted on the sides. The tower has 40 big fans and 5,000 filters to clean the air.
• This tower has been established as a pilot project and detailed studies will be conducted on its performance.
• Once satisfactory results are received about the tower’s effectiveness, then the model will be replicated and smog towers will be established all over Delhi,
• The Delhi pollution control committee was the nodal authority for building the tower. IIT-Bombay and IIT-Delhi were technical advisors and Tata Project Ltd. executed the project.

Working of the Smog tower

• Polluted air is sucked in at a height of 24 m, and filtered air is released at the bottom of the tower, at a height of about 10 m from the ground. 
• When the fans at the bottom of the tower operate, the negative pressure created sucks in air from the top. 
• The ‘macro’ layer in the filter traps particles of 10 microns and larger, while the ‘micro’ layer filters smaller particles of around 0.3 microns.
• The downdraft method is different from the system used in China, where a 60-metre smog tower in Xian city uses an ‘updraft’ system — air is sucked in from near the ground, and is propelled upwards by heating and convection. 
• Filtered air is released at the top of the tower.

Likely impact 

• Computational fluid dynamics modelling by IIT-Bombay suggests the tower could have an impact on the air quality up to 1 km from the tower.
• The actual impact will be assessed by IIT-Bombay and IIT-Delhi in a two-year pilot study that will also determine how the tower functions under different weather conditions, and how levels of PM2.5 vary with the flow of air.
• An automated Supervisory Control and Data Acquisition (SCADA) system in the tower will monitor air quality. Levels of PM2.5 and PM10, besides temperature and humidity, will be measured constantly, and will be displayed on a board atop the tower.

The Indian Express link- https://indianexpress.com/article/explained/delhis-new-smog-tower-the-technology-the-impact-the-evidence-7467471/ 

Question- Write a short note on technology used in a smog tower.