Smog-Sucking Electrostatic Vacuum Cleaners May Scrub Polluted Air

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Residents of Beijing may enjoy pockets of fresh air, thanks to giant devices that remove particulates out of the city’s filthy sky.

The murky brown smoke that hangs over Beijing and other industrial cities has long presented a health challenge to China. Unwilling to shut the factories and coal-burning plants that cause pollution, authorities instead are seeking novel solutions. Proposals have included seeding clouds to make rain to wash particulates out of the sky and equipping bicycles with pedal-powered generators that pump fresh air into riders’ helmets. The latest idea comes from Dutch artist Daan Roosegaarde, who hopes to create bubbles of clean air in various pockets around the Beijing.

Roosegaarde’s positive–ionization “vacuum cleaner” uses high-voltage, low-amp electricity to create an electrostatic field. Particles flowing across the field—enclosed in a box—become positively charged and attach themselves to a grounded electrode, which need to be scraped clean periodically. (Roosegaarde plans to turn the stuff into “diamond” rings, with a cubic-centimeter stone representing a cubic kilometer of smog.)

The system was actually invented by Delft University of Technology researcher Bob Ursem, who came up with the idea of ionizing smog particles after watching tiny bits of salt, dust and organic matter flow off the Atlantic Ocean onto a Dutch beach. “They floated into the dunes toward some bushes,” Ursem says, “and there was a lift effect, carrying them above the bushes.” The particles, negatively charged from friction, were avoiding contact with negatively charged foliage. “They floated above the bushes, indicating that the electrical force is greater than the gravity force,” Ursem says.

He replicated the phenomenon using dust in his lab, and he devised a way of reversing the charge on the particles using the electrostatic field. Under lab conditions, he says, his invention doesn't even require a ventilation system to draw air across the coils of electrified copper wire. The force of positively charged particles attaching themselves to a ground makes room for other particles to follow, soon creating an “ionic wind,” Ursem says.

But in reality, the Beijing air cleaner would require fans, say officials the research and development firm Environmental Nano Solutions (ENS) Europe, which bought the concept from Delft University and is developing it for commercial marketing. And it would not—as portrayed in Roosegaarde’s animated depiction of the device in action—produce an actual patch of blue sky above.

Written By: Edmund Newton
continue to source article at scientificamerican.com

6 COMMENTS

  1. The latest idea comes from Dutch artist Daan Roosegaarde, who hopes to create bubbles of clean air in various pockets around the Beijing.

    MMmmmm! This reminds me of a protest song I wrote around 1970!
    Here’s the end of it!

    I soon met a man who lived down by the Mersey,

    Way out in the country – so wild and so fair!

    He said to me, “There’s a funny smell here!”

    I said, “It’s a secret, We call it ‘fresh air’! “

    CHORUS:

    There’s holes in the mountains,

    Roads in the valleys,

    There’s muck in the rivers – and oil in the sea,

    Fortunes were waiting,

    For men who took ‘em,

    and only the debris, is waiting for me.

    …….. . . . .. . .. . . .. . . . ..

    When the sea is all poisoned, – the rivers all rotten,

    The air is quite caustic – that could be quite soon,

    Don’t worry about it – that’s counter-productive,

    By then we’ll be ready – to live on the Moon!

    CHORUS.

  2. It is of course possible to use natural solar-powered trees to remove particulate pollutants locally!

    http://www.es.lancs.ac.uk/people/cnh/UrbanTreesBrochure.pdf
    >

    We grouped the tree species according to their effect on air quality. They are grouped below as;

    trees that have the greatest capacity to improve air quality.

    • Silver birch, Scots pine Norway maple, Larch, Field maple, Common alder, Ash, ….. . . .

    • mature, mixed woodland captures airborne particles at approximately three times the rate of grassland

    • trees on the edge of woodland are
      more effective at capturing airborne
      particles than the trees in the centre
      of the wood because they have larger
      leaf areas and are exposed to the
      wind.

    The main concern over airborne particles in cities is their effect on human
    health. A number of epidemiological studies have shown that a rise in PM10
    concentrations of 10g m-3 (as a 24 hour average) is associated with an increase in mortality of 1%. The reduction in PM10 concentrations which would result from future tree planting would therefore be beneficial to human health.
    Quantifying this benefit is more difficult. However, using these health statistics
    and our predictions of the effects of tree planting on urban air quality, we estimate that doubling the number of trees in the West Midlands could reduce excess deaths due to particles in the air by up to 140 per year.

    There are however some trees which create more pollution than they remove. (See page 6 of the link)

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