Airborne pollution is a major issue in China, with local hospitals opening up "smog clinics" and waves of city-dwellers migrating to more rural areas to escape. While Chinese officials are pursuing "cloud seeding" as a way to control pollution, a Zhejiang University professor thinks he has a better idea: Sprinklers. Big ones.
Yu Shaocai is a former U.S. Environmental Protection Agency employee and an expert on "wet deposition," a process by which falling raindrops or snowflakes "scavenge" aerosol particles from the air. In other words, they collect and deposit the polluted particles on the ground. This why the air is usually clearer after a rainy day.
In an article published in the January issue of Environmental Chemistry Letters, Shaocai proposes a novel way to kickstart wet deposition in polluted cities: By faking it with geoengineered urban infrastructure. In simpler terms, Shaocai's plan involves attaching giant sprinklers, like showerheads, to the exterior of skyscrapers, and spraying water into the atmosphere above heavily-polluted cities to clear out toxins and gases.
Beijing on January 16. Image: ChinaFotoPress.
As you might expect, Shaocai has his detractors. Speaking to The South China Morning Post, one scientist questions where the water would come from and how it would be recycled, but then grudgingly admits that "assuming his team can find a system that works, and they've done enough economic analysis and considered the handling of water resources, this could be a viable option."
Shaocai imagines attaching sprinklers to the CCTV building in Beijing. Image: Lintao Zhang/Getty.
Then, of course, there's the cost of retrofitting skyscrapers with watering devices, not to mention designing a system that's safe during storms and high winds. Or engineering a system smart enough to not overwater, or freeze up on cold days.
In short, this a theoretical paper in a chemistry journal—not a workable plan. Yet.
Shaocai told the SCMP that he and his students plan to carry out tests at Zhejiang University, first, and then in Hangzhou. In his paper, he imagines the architectural implications of attaching sprinkler systems to Beijing's CCTV building or Shanghai Dongfang Tower, including some faintly absurd Photoshop composites:
Shaocai's plan sounds (and looks) like the stuff of turn-of-the-century science fiction. But it's actually fairly logical. Most urban pollution drifts below 300 feet, which means existing towers offer the perfect platform for wet deposition. And, of course, skyscrapers are usually located in parts of cities where humans spend the most time commuting—so it makes sense that man-made "rainouts" would need to mirror them on the map.
A rocket launcher used to seed clouds to induce rain is seen at a station of the Beijing Meteorological Bureau in Beijing. AP Photo/Ng Han Guan.
In December, the China Meteorological Administration announced a $277 billion plan to begin large-scale cloud seeding around Chinese cities, clearing pollution by "firing rockets carrying a payload of silver iodide particles into the clouds." But there are questions about whether cloud-seeding will actually work to spur wet deposition, since existing snow and rainfall should already be doing that job.