The first smog tower has been set up in the city of Delhi ahead of the infamous winter season, which sees the pollution levels increase.
The smog tower is a solid structure that consists of fans for pulling the air and purifying it before releasing back.
The structure is as high as 8 storey building and built of concrete. There are 40 fans, divided equally on four sides of the structure.
The fans can give out 25 cubic metres per second of clean air. The total capacity of the structure is 1,000 cubic metres per second.
Two layers of filters have been fit inside the tower. They have been imported from the US along with the fans.
The technology being used in the tower is based on ‘downdraft air cleaning system’. This technology was developed by University of Minnesota.
The technology has been replicated by IIT-Bombay for implementing it locally. The structure has been constructed by Tata Projects Limited.
The polluted air is sucked from the top of the tower. The filtered air is then released from the bottom through fans.
The negative pressure created due to release of air at the bottom allows the air to be sucked at the top.
This air is made to pass through macro-filters that absorb particles of 10 microns and larger. The micro-filter traps smaller particles of around 0.3 microns.
Difference in technology
The technology used in Delhi is different from the updraft system used in China’s Xian city, which has a 60m high smog tower.
The Chinese model absorbs polluted air from the base of the tower. It is then moved upwards by heating and convection.
Studies conducted by IIT-Bombay say that the effect could be felt within 1km radius of the tower. A pilot study will be carried out to study detailed effects.
The air quality level of PM 10 and PM 2.5 will be consistently monitored through Supervisory Control and Data Acquisition (SCADA) system.
The aim of the project will be to provide pure air in a given area. However, there is no clear evidence of success.
Scientists are demanding structural changes to combat air pollution rather than short term benefits. Preventing stubble burning is among the top priority.
Since the air flow pattern in a given area is dynamic, there are high chances that the tower may prove futile.
Smaller versions of smog towers have been installed in Lajpat Nagar, Krishna Nagar and Gandhi Nagar by Gautam Gambhir foundation.