China has constructed Xian smog tower, an experimental air purifying tower touted to be the world’s biggest at height of over 100 meters (328 feet) in an attempt to fight air pollution.
The tower is built in Xian in Shaanxi province and has brought positive effect on chronic smog problem in China. It is undergoing testing by researchers at Institute of Earth Environment at Chinese Academy of Sciences.
Xian smog tower
Xian smog tower project was announced in 2015 to find low-cost method to artificially remove pollutants from atmosphere such as PM2.5, nitrates and sulphur dioxide which are the most harmful to human health.
The polluted air is sucked into glasshouses of tower and is then heated up by solar energy. The hot air then moves through multiple cleaning filters and helps in reducing air pollution. The system in air purifier also works during winters as coatings on greenhouses enable glass to absorb solar radiation at higher efficiency.
According to its original design, the full-sized tower will reach 500 metres (1,640 feet) high with diameter of 200 metres (656 feet). This tower size will capture greenhouses in nearly 30 square kilometres and will be capable of purifying the air for small-sized city.
During the tests, the tower has managed to produce more than 10 million cubic metres (353 million cubic feet) of clean air day since its launch. It was able to bring down the smog to moderate levels the day when air quality was severe. However, the results were preliminary as of now. It has also improved quality of air after observations were made over distance of 10 square kilometers in the past few months.