China has an awful smog problem, which means its cities smell, are difficult places to breathe in, and, in the most unfortunate extreme, give children cancer. But its authorities hope that it may have found a solution, in the form of artificial rain.
According to local news reports, the China Meteorological Administration is planning to allow local weather authorities to use cloud seeding to create rain—which should in turn clear the smog. Or so they hope.
Part of a £140 billion investment to tackle the problem, the initiative will go live in 2015, according to leaked documents. But while we've long been able to create manmade rain, just how effective will it be at clearing smog? New Scientist ponders that question:
The technique the Chinese use involves firing rockets carrying a payload of silver iodide particles into the clouds. Ice crystals then form from super-cooled liquid water in the clouds, using the particles as nucleation points. The crystals fall as rain or snow depending on the temperature below. The idea is that the artificial precipitation should clear the smog below... [But] smog is made of particulates of soot and dust, which should already have acted as ice nuclei. If it hasn't rained already... then adding more particulates in the shape of silver iodide won't help.
So, it might sound like a great idea, but it remains to be seen whether or not it will work in practice. Here's hoping, for all those that live in China's smog-ridden cities, that it at least helps a little. [New Scientist]
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