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Community / Public space

Chinese cities are using water cannon to clean their air

In the summer months, Chinese cities don’t just get hot: they get smoggy, too. Beijing has long been known as the country’s pollution capital, but data released in March showed that, in 2013, nine other cities suffered more days of smog than the capital. The news prompted Chinese premier Li Keqiang to “declare war” on pollution.

And that war is being fought using cannon.

Over the last few months, pictures have emerged showing giant, hair dryer-like machines, mounted on trucks in the streets of several Chinese cities. These can blow water vapour up to 200 feet into the air: the idea is that water droplets from these “mist cannons” stick to pollution particles, and pull them to the ground.  They come with a hefty price tag: most cost city governments between 700,000 and 900,000 yuan (that’s $113,500-$146,000).

The cities that have made greatest use of the cannon seem to be those of Heibei, the province south of Beijing, where many of the cities with the worst pollution are located. Here’s one in Zhangjiakou:

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Image: Xinhua.

Unfortunately for city governments and their war on pollution, Pan Xiaochuan, an environmental expert from Peking University, told Xinhua last month that the cannons aren’t actually very effective. The machine can reduce pollutants for a short time after the water is sprayed, he said – but “its effects don’t last long”. And then the cannon moves on, to another location: it offers, at best, a moment of relief.

Despite this, the cannons are still being used: Chongqing started using one just last week, though city officials say it was hired to fight “summer heat”, not smog.

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Chongqing’s new cannon. Image: People’s Daily.

In other words, they’ve basically spent around 750,000 yuan ($121,500) on a movable sprinkler to keep the city cool. Can’t argue with that.
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