![The world's largest air purifier "smog filtering tower" (smog free tower) is being installed outside the Dalian International Conference Center in Dal Stock Photo - Alamy The world's largest air purifier "smog filtering tower" (smog free tower) is being installed outside the Dalian International Conference Center in Dal Stock Photo - Alamy](https://c8.alamy.com/comp/W7REMC/the-worlds-largest-air-purifier-smog-filtering-tower-smog-free-tower-is-being-installed-outside-the-dalian-international-conference-center-in-dal-W7REMC.jpg)
The world's largest air purifier "smog filtering tower" (smog free tower) is being installed outside the Dalian International Conference Center in Dal Stock Photo - Alamy
![The world's largest air purifier "smog filtering tower" (smog free tower) is pictured outside the Dalian International Conference Center in Dalian cit Stock Photo - Alamy The world's largest air purifier "smog filtering tower" (smog free tower) is pictured outside the Dalian International Conference Center in Dalian cit Stock Photo - Alamy](https://c8.alamy.com/comp/W7PMT2/the-worlds-largest-air-purifier-smog-filtering-tower-smog-free-tower-is-pictured-outside-the-dalian-international-conference-center-in-dalian-cit-W7PMT2.jpg)
The world's largest air purifier "smog filtering tower" (smog free tower) is pictured outside the Dalian International Conference Center in Dalian cit Stock Photo - Alamy
![The world's largest air purifier "smog filtering tower" (smog free tower) is pictured outside the Dalian International Conference Center in Dalian cit Stock Photo - Alamy The world's largest air purifier "smog filtering tower" (smog free tower) is pictured outside the Dalian International Conference Center in Dalian cit Stock Photo - Alamy](https://c8.alamy.com/comp/W7PN4C/the-worlds-largest-air-purifier-smog-filtering-tower-smog-free-tower-is-pictured-outside-the-dalian-international-conference-center-in-dalian-cit-W7PN4C.jpg)