Clean and high

These are skyscrapers with a difference: they can remove large amounts of sulphur dioxide, ozone, soot and other polluting particles from the air

 
Published: Friday 28 February 1997

Changing skylines: tall concre skyscrapers could soon be one of the solutions to urban pollution problems. A proposal to that effect has been introduced by Melvin Prueitt, a scientist at Los Alamos National Laboratory in New Mexico, us, who has been awarded four patents for several tower configurations.

These towers will transform hundreds of cubic km of hot polluted air into clean, cool air daily. This will generate electricity and even produce fresh water. The skeletal structure of the towers is provided by 10 steel vertical rods placed in a circle around which teflon-coated fibreglass is wrapped. Turbine blades mounted in tunnels within the fibreglass power water pumps, which spray charged water into the air in a fine mist. The water used in the system can be fresh, saline or even the chlorinated sewer variety.

The charged water droplets at the tower-top attract and capture pollutant particles from the air as they flow into the wide mouth of the tower. The water spray at the top of the tower makes the air cooler and heavier. These heavier air droplets drop down through the tower, creating a downdraft behind them, helping to draw more polluted water into the tower. As the humid layer of dirty air falls, the air compresses and increases in temperature. As a result, water droplets continue to evaporate.

Much of the water evaporates as the air falls through the tower. At the base, a spray of larger water drops collect and deposit most of the pollutants into catch basins in the tunnels within the fibreglass wrap-around. The end product is a clean, cool breeze from the tunnels into the surrounding cityscape, at or near ground level.

This cycle creates a continuous downflow of air at a speed of about 15-25 metres per hour through the tower. The air then goes out through the turbines at the base of the tower. This air speed also powers the turbines. As the turbines generate more electricity than is used, the excess can be sold to the local power utility. The structures are expected to have a 40-year working lifetime.

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