A 100m tall experimental air purifier has been built in Xi’an, the capital of China’s central Shaanxi province.
The tower, which is being tested by researchers from the Institute of Earth Environment at the Chinese Academy of Sciences, has noticeably cleaner air over an area of 10 sq km since being turned on last year, according to the South China Morning Post.
The tower sucks in polluted air and funnels it into greenhouses at the base of the structure, which heat the air before it is filtered and vented. The expelled air contains 15% less particulate matter than it did before being scrubbed.
The greenhouses are powered by solar radiation and are able to run in winter as well as summer. Cao Junji, head of research, said: "It barely requires any power input throughout daylight hours. The idea has worked very well in the test run."
Cao and his team are now planning a 500m tall and 200m wide tower, with greenhouses covering 30 sq km, that would be able to purify air for a small city.