Daan Roosegaarde reached into the pocket of his suit jacket, pulled out a plastic bag filled with black powder, and waved it around.
"This is Beijing smog," Roosegaarde said, before gesturing to the seven-metre tall, gently humming metal tower we are stood next to in the Chinese capital's art district, 798. "We collected it from the tower yesterday. Incredibly disgusting."
Dutch designer Roosegaarde's smog souvenir may be disgusting, but it's the byproduct of an invention that he has touted as a potential alleviator of China's pollution problems. His "smog-free tower" sucks air, filters it with ion technology, with Roosegaarde having explained: "By charging the Smog Free Tower with a small positive current, an electrode will send positive ions into the air. These ions will attach themselves to fine dust particles. A negatively charged surface — the counter electrode — will then draw the positive ions in, together with the fine dust particles. The fine dust… is collected together with the ions and stored inside of the tower."
With the dust collected, the tower then spews out cleaner air through vents, creating a "bubble" in the area surrounding it that contains, according to Roosegaarde, up to 70 percent fewer pollution particles than the pre-cleaned air.
China could do with its air being filtered, with the government having declared "war" on pollution many times in recent years. New Chinese environmental laws introduced in 2015 demonstrated that authorities were serious in tackling the roots of the problem, cracking down particularly hard on polluting factories.
According to Roosegaarde, officials from China's Ministry of Health visited him at his Rotterdam-based company, Studio Roosegaarde, to find out more about the tower. And more government officials are visiting it this week, as the tower begins a tour of five Chinese cities.
But is this more than just a massive publicity win for the trendy Dutch studio? Reports about pollutant dust filtered by the tower being used to make diamonds made it sound too good to be true: a mega-bling vending machine sucking smog then firing out sparklers.
"This is not just a symbol or artistic gesture," Roosegaarde said.
Still, we have some questions.
IS THE TOWER MORE THAN JUST A MASSIVE AIR PURIFIER?
"That's like saying a satellite going to the moon is the same as driving a car," Roosegaarde told me.
Still, by making air around it cleaner, the tower is essentially doing the same job as the indoor air purifiers that have fuelled a recent boom industry in China, just on a larger scale. Roosegaarde and co-creator Bob Ursem, nanoparticles expert at Delft University of Technology, say their tower can churn out 30,000 cubic metres of clean air an hour.
This makes it a symptom-treater rather than something addressing the causes of pollution, of course. Roosegaarde says it is designed to be placed in public parks.
"By making a place where people can feel their air quality difference you can create engagement with people [about wider pollution issues] so they begin to think, 'We need to make a whole city smog free,'" he said.
CAN SMOG COLLECTED FROM IT BE TURNED INTO DIAMONDS?
Roosegaarde has benefited from media speculation about this process but now distances himself from it.
"We never used the word diamond," he said.
Roosegaarde claims that the firm did get diamonds from pollution dust made, but as the process required so much energy it didn't chime with the firm's environmentally friendly ethos. Instead, they sell jewelry featuring little blocks of compressed pollutants.
To continue the smog-into-diamonds idea would be doable but, according to Clive Hill, founder of Washington, DC-based synthetic diamond firm WD Lab Grown Diamonds, it'd be tough. The process involves putting carbon under incredibly high temperatures and amounts of pressure.
According to Roosegaarde, smog particles collected from his tower before it arrived in Beijing were 42 percent carbon; he has been quoted as suggesting that diamonds could be made from such matter.
However, as Hill told Motherboard, "You'd have all sorts of contaminates [with that carbon percentage]. I don't think you could make a diamond at 42 percent. You'd have to purify it, and if you didn't get the purity too good you'd have a very funny looking diamond."
WILL IT BE ROLLED OUT ACROSS CHINA?
This, rather than making diamonds, is Roosegaarde's end game. Although the tower's only China appearance so far has been as a showcase in Beijing, he is targeting an uptake of 800 units in cities across China. He is collaborating with Chinese investment and production firm Winworld, based in the northeastern city of Tianjin, to plan production.
"That's why I'm here," he says. "[To plan to roll out] anything less than 800 would be naïve." This will require government interest being converted to firm orders—Roosegaarde's biggest challenge yet.
The prices of the towers have not been revealed. While they don't strike me as being cheap, Roosegaarde is characteristically confident they will be popping up around China before long.
"What's the price of clean air?" he says. "What's the price of living two years longer? What's the price for having your children being able to play outside?"
Probably a lot more than it costs to stick a big smog-sucking tower in a park. But that this thing has got as far as China is still seriously impressive. Whether it will stay here or not is still up in the (temporarily cleaner) air.