How Some Water and Tall Buildings Could Fix China's Pollution Problem
It's like a scene from another world - picture after picture of China's landscape erased by a smog so heavy that, back in September, the Chinese government was finally compelled to lay out a plan to fight the problem. The measures included closing down factories and improving fuel quality, but according to Shaocai Yu, a researcher from Zhejiang and North Carolina State universities, officials may be overlooking one very straightforward solution: water.
The same way rain removes dust from the air, the system Yu describes in the journal Environmental Chemistry Letters includes releasing water into the atmosphere to collect, or scavenge, particulate matter - only in this case from sprinklers positioned at the top of tall buildings.
Yu got the idea while watching a garden being watered. "I immediately thought that we can clean air pollution by spraying water into the atmosphere like watering a garden," he told Nature World News in an email.
Besides being entirely free of harmful chemicals, the water could be collected and reused, meaning it would not exacerbate current water shortages. Water taken from lakes and rivers that is then used nearby would simply fall back to the ground and make its way back to its source, he explained. In other cases, the water could simply be collected in a big container and reused over and over again, as well being employed for other purposes. Either way, the researcher who has studied pollution and precipitation for more than 30 years does not believe the used water would have a "significant impact" on water quality upon its return.
Yu estimates that the plan could reduce the fine particle load to 35 micrograms per cubic meter - a major decline from current levels that sometimes jump to more than 10 times that amount, depending on the day and city. An image taken by a NASA satellite in December revealed that things had gotten so bad, air pollution had replaced the Great Wall as visible from space. On the day the picture was taken, Beijing hit 480 micrograms per cubic meter. Back in 2010, the automated air quality readings posted by the Twitter account belonging to the US embassy in Beijing deemed the air "crazy bad" after the particle load exceeded the Environmental Protection Agency's maximum score of 500, soaring to 562. The tweet was quickly deleted, but not before catching the attention of its followers.
Depending on how much water was used, the method's effects could be essentially immediate, though it would have to be carried out on a daily basis in order avoid accumulation, Yu noted.
"With careful and considered evaluation beforehand for each area in the cities, this geoengineering approach can be environmentally safe without significant side effects. It can also be deployed easily within communities and on a massive scale at low cost," he said in a statement. "If you can spend half an hour watering your garden, you can also spend 30 minutes watering your ambient atmosphere to keep the air clean with this technique."
Going forward, Yu plans on putting the experiment to the test in Hangzhou, the city where Zhejiang University is located.
"Definitely, more research is needed in designing a specific delivery system that is capable of delivering the water in the right manner, right place, and right time to encourage the most effective precipitation scavenging for air pollution at a low cost," he said.
A study released in July by the Proceedings of the National Academy of Sciences estimated that China's air pollution significantly shortens the lives of those exposed to it. Led by researchers from Massachusetts Institute of Technology, the report estimates that the 500 million people living north of the Huai River, a major body of water located midway between the Yellow River and Yangtze River, are set to lose a total of 2.5 billion years due to the amount of coal used to power boilers in the region.