'World's biggest air purifier' on trial run in Xi'an

Think your air purifier's big?

The lead researcher behind a 100-metre high experimental smog-sucking tower in Xi'an (Shaanxi province) claims that the quietly purifying monolith is already making a significant positive impact on the city's air quality, according to the South China Morning Post. The tower, now only in the stages of early testing, could be a practical and sustainable tool used all across China as a part of the country's efforts to cut down on air pollution.

The current tower is said to work by using solar greenhouses (spanning about half a football pitch) at the base of the tower to heat up dirty air, which then rises up into the tower and through its many filtration systems for cleaning, with the cleaned air then circulating out the top of the tower and throughout the surrounding area. According to the lead researcher Cao Junji, the tower produces more than 10 million cubic metres of clean air a day and it has an effective area of about 10 square kilometres. Furthermore, Junji states that the tower downgrades severe pollution days to moderate levels with an average PM2.5 reduction of 15 percent (a highly ambitious claim).

The tower, which began construction in 2015 and was finished last year for an undisclosed cost, was named the 'world's biggest air purifier' by its research team and operators from the Institute of Earth Environment at the Chinese Academy of Sciences. The only other tower close to it in the world is the Smog Free Tower at 798. Built by Dutch artist Daan Roosegaarde and his team in September 2016, it was ultimately deemed too small (standing at a mere seven metres) to have any real effect on Beijing's choking smog. It was nonetheless kept in China for 'educational purposes'. The non-experimental version of the tower in Xi'an is projected to reach 500 metres in height and 200 metres in diameter.

The quiet, energy-efficient air purifying towers are a potential cost-efficient solution to China's smog problem. However, building many of them to cover a large and dense city is highly impractical when considering how much space they require, the one in Xi'an having been built in one of the city's outer industrial zones. Nonetheless, the towers represent China's continued efforts to aggressively address its air quality problems.

Hit 'Read more' for our interview with Daan Roosegarde, designer of Beijing's Smog Free Tower.

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