The smog tower at Connaught Place here has a noticeable impact on air pollution up to a distance of 300 metres, Delhi Environment Minister Gopal Rai said on Friday.
Sharing the data collected over a year, he said the giant air purifier can cut down air pollution by 70 to 80 per cent within a radius of 50 metres and by 15 to 20 per cent beyond 300 metres.
Chief Minister Arvind Kejriwal inaugurated the over 24-metre-high smog tower at Connaught Place on August 23 last year.
The city government had formed a team of experts from IIT-Bombay to study its impact over two years.
Officials had earlier said the Rs 20 crore smog tower can purify the air in a one-km radius at a rate of around 1,000 cubic metres per second.
"The data collected over the last one year showed the smog tower has a noticeable impact on air pollution within a radius of 300 metres," Rai said.
An official pointed out that a bulk of data was collected in the summer and monsoon season when the concentration of particulate matter was "anyway very low" and hence, "one cannot expect a significant impact of smog tower at a longer distance when the air is already clean".
He said the smog tower did not operate at maximum capacity initially -- leaks allowed entry of polluted air and filters would get dislodged at high fan speed while high humidity ruined them.
"The fan speed has improved from 50 per cent in the initial months to 100 per cent now and the filters are stable," he said.
"We expect a greater impact on the ambient air quality in the upcoming winter season when the system will be operated at optimum level. The tower is operating close to its designed capacity (90 per cent)," the official said.
IIT-Bombay will submit a final report after a year. During this time, detailed investigations will be carried out to evolve more operational parameters, cut costs and maximize the efficiency of the smog tower, he said.
Rai said the construction of more smog towers in the national capital would depend on the success of the pilot project.
The experts are also trying to figure out ways to make smog towers cost-effective, he added.
Another official said the two-year study is also focusing on reducing the size of the structure, minimizing energy consumption, and developing design parameters and specifications for low-cost indigenous filters and fans.
The smog tower at Baba Kharak Singh Marg has 5,000 coarse filters and 5,000 fine filters developed by experts at the University of Minnesota which also helped design a 100-metre-high smog tower at Xian in China.
The Supreme Court had in January 2020 directed the central government to construct a smog tower to reduce pollution at Anand Vihar and the Delhi government to install another such structure at Connaught Place in three months.
