Four Ideas to Fix Beijing's Smog Airpocalypse, And One That Will Work

The worst smog of the year so far swept into Beijing this week, coating the city in a grainy, deep grey murk on par with what the city endured in 2013, pictured above (though you'll see it's popping up again today). China is trying, hard, to get its air quality problem under control, and is considering some seriously wacky ways to do it. Unfortunately, the only one that will work is also the most difficult.

If you're in Beijing right now, here's what you're dealing with: Extraordinary levels of a small particulate called PM2.5, which is great at hanging out in midair for long periods of time. PM2.5 comes from industrial sources and wood-burning fires, and it's as dangerous to human lungs as it is good at staying put. The World Health Organization recommends that the max amount of the stuff we can breath is 25 micrograms per cubic meter. Beijing hit 568 today.

The really startling thing, of course, is that this isn't all that uncommon. The concentration has hit 993, almost twice as bad as this week's levels, before. Smog comes, you don a mask and stay inside as much as possible, and smog goes. China is actually pretty good at controlling it when it matterswhen world leaders were in town for APEC's annual summit in November, locals jokingly described the clear sky as "APEC blue." Pollution is so intense, it can be seen from space:

But temporary respites like the one APEC brought don't help actual residents all that muchwhich is why China has become a hotbed of smog-busting ad hoc design.

The big tool in China's smog-busting arsenal is cloud seedingSoviet Russia brought the concept to China in 1958, as QZ explained in a great story on artificial rain a few years ago. The idea is fairly simple: A plane (or rocket launcher) dumps chemicalsfrom potassium iodide, to liquid propane, to silver iodideinto an existing cloud, creating ice particles that get heavy and fall to Earth as "rain."

Rain "washes" the air of PM2.5 particles; the water molecules collect the toxic particulates and then bring them down to the ground. Technically, it's called "wet deposition," and according to QZ, China now makes 55 billion tons of artificial rain to aid in the process every year.

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.

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Four Ideas to Fix Beijing's Smog Airpocalypse, And One That Will Work