China is one of the world’s largest economies in the world, coming in second to the U.S., and has reaped its benefits accordingly. But despite such economic prosperity, the country struggles to keep a cap on the staggering pollution levels in Chinese cities. With pollution levels incapacitating citizens across China, the Chinese City of Xian is undergoing testing of an air purifier in an effort to find a low-cost and effective method to artificially remove pollutants from the air.

Developed by researchers at the Institute of Earth Environment at the Chinese Academy of Sciences, the “world’s biggest air purifier” in China’s Northern Shaanxi province is a cylindrical tower that is more than 100 meters (328 feet) high, and can provide clean air for residents within a 10-kilometer (6.21-mile) radius. The tower’s purifying capabilities are reinforced by greenhouses at the base of the tower that absorb polluted air, which then heat and filter the air and send the purified air up the shaft and back into the atmosphere.

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Xian’s air purifying tower that is currently being tested. (CC: SCMP)

The greenhouses, which together are about the size of half a soccer field, require little to no external power since they are mostly powered by solar energy. And even in the winter when smog overhead remains thick, the glass around the greenhouses manages to extract a significant amount of energy from the sun. In order to monitor the success of the pilot project, researchers positioned a dozen towers around the city.

Cao Junji, head of the research team leading the project, claims that the air purifier has managed to provide Xian’s residents with 10 million cubic meters (353 million cubic feet) of purified air since the project began testing. Even on severely polluted days in the city, the tower was able to reduce overall PM 2.5 levels by 15 percent on some occasions.

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A map indicating the location of the air purifier in the city of Xian. (CC: SCMP)

Other initiatives aiming to purify air in China have also popped up in recent years. In Fall 2016, Studio Roosegaarde’s Smog Free Tower, a tower that purifies air and turns the pollutants in diamonds, toured five cities, including Beijing – the city that inspired the project to begin with. In July of last year, Italian architect Stefano Boeri announced plans to design a forest city to reduce the pollution emitted by the nearby industrial city of Liuzhou.

The air purifier project initially began back in 2015 and construction of the tower itself was completed last year. Although Junji says the testing period’s results seem promising, more detailed results are yet to be released this coming March. According to the project’s preliminary plans, the tower could stand as high as 500 meters (1,640 feet), with greenhouses that could span about 30 square kilometers (11.6 square miles).

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