Air purifying tower extracts smog particles Tuesday, 05 July 2016

Rotterdam-based designer and engineer Daan Roosegaarde, after seeing all of Beijing covered in smog from his hotel room, was inspired to build a giant air purifying tower that takes in polluted air, and cleans it of smog using ionisation technology.

The Smog Free Tower is based on ionisation technology that was previously used only on a small scale in hospitals and other clean facilities to purify air in small areas. The seven-metre high structure by Studio Roosegaarde is represents the first time the technology is being applied in the public space.

The ionisation technology works by charging the Smog Free Tower with a small positive current. An electrode sends positive ions into the air, which gives the fine dust particles a positive charge. A negatively charged surface, the counter electode, then draws the positive ions in together with the fine dust particles, collecting them inside the tower.

According to Roosegaarde, the process can capture ultra-fine smog particles which regular filter systems fail to do, including PM2.5 and PM10 sized pollution particles, creating a bubble of air around the tower which is around 75 percent cleaner than the air in the rest of the city.

With the help of 1577 backers on Kickstarter, who contributed over 113,000 Euros to their project, Roosegaarde and his team built the tower, and piloted it in Rotterdam. They are currently touring the world with their tower, starting in Beijing, where it stands in a park, filtering the air.

The Smog Free Tower also uses very little energy, with 30,000 cubic metres of air cleaned per hour on 1700 watts, and can run entirely on energy derived from renewable sources. It also requires low maintenance, and is able to clean large quantities at very high speed. Additionally, unlike other ionisation techniques, the tower does not create ozone as part of the process.

Roosegaarde's team does not discard the smog particles collected by the tower. As part of the Kickstarter campaign, they harvested the particles, compressed them into cubes under high pressure, and encapsulated them in clear plastic as mementos. Each cube represents 1000 metres cubed of clean air.

This project represents the world’s largest air purifying towers currently in existence, and the plan is to popularise the process to make it both environmentally sustainable and aesthetically pleasing. The researchers are also working on enabling solar powered towers.

Don't forget to register for the Australian Engineering Conference 2016 in Brisbane on November 23-25.