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Urban Greening

August 1, 2012

Strategically placed grass, ivy, and other greenery can significantly improve air quality in urban centers.



Greener city air.  I’m Bob Hirshon and this is Science Update.

Making concrete jungles greener could reduce two major air pollutants by up eight times more than previously thought.  This according to research at Lancaster University in England.  Atmospheric scientist Thomas Pugh, now at the Karlsruhe Institute of Technology in Germany, says they looked specifically at “street canyons” – urban corridors surrounded by tall buildings.

THOMAS PUGH (Lancaster University/Karlsruhe Institute of Technology):

And the way that these canyons work aerodynamically, is that they tend to trap the air inside them.  So that the air inside the canyon doesn’t mix very well with the air above the canyon, in the free atmosphere, if you like.

That traps pollutants like nitrogen dioxide and airborne particles.  But it also makes it easier for grass, ivy, or other green surfaces to soak them up.  The study suggests that covering downtown walls and roofs with greenery could have a significant impact on pollution and public health.  I’m Bob Hirshon for AAAS, the Science Society.

Lining building walls and roofs with greenery, as shown, could significantly reduce air pollution in urban corridors. Reprinted with permission from Environmental Science & Technology 2012 46 (14), 7692-7699. Copyright 2012 American Chemical Society.