Air purification tower cuts PM2.5 by 15%: researcher

Testing has shown that 60-meter-tall air purification tower in Xi'an, capital of northwest China's Shaanxi Province, can cut the average PM2.5 density by 15 percent over an area of 10 square kilometers.

Researchers released the test results of the tower's purification capability at a press conference on Tuesday.

On severely polluted days, the tower can purify five million cubic meters of polluted air on a daily basis, according to Cao Junji, researcher with Institute of Earth Environment under the Chinese Academy of Sciences.

The air purification tower, with a diameter of 10 meters, is a part of a scientific research project led by several organizations including the institute.

A glass enclosure surrounds the base of the tower. The polluted air inside the enclosure is heated by solar energy. The hot air rises and moves freely inside the tower, passing through layers of filters.

The tower was built in 2016 in Xi'an, a city which has long been troubled by heavy air pollution in winter. The tower is still undergoing testing.

The causes of air pollution in China are complicated and it is difficult to work out a universal solution, Cao said, admitting that the purification tower project is a supplementary method and cannot replace the major measures such as controlling pollution at the source.