Green Plants Reduce City Street Pollution Up to Eight Times More Than Previously Believed

Photo credit: Michael Fiegle

Via ScienceDaily:

Trees, bushes and other greenery growing in the concrete-and-glass canyons of cities can reduce levels of two of the most worrisome air pollutants by eight times more than previously believed, a new study has found. A report on the research appears in the ACS journal Environmental Science & Technology.

Thomas Pugh and colleagues explain that concentrations of nitrogen dioxide (NO2) and microscopic particulate matter (PM) — both of which can be harmful to human health — exceed safe levels on the streets of many cities. Past research suggested that trees and other green plants can improve urban air quality by removing those pollutants from the air. However, the improvement seemed to be small, a reduction of less than 5 percent. The new study sought a better understanding of the effects of green plants in the sometimes stagnant air of city streets, which the authors term “urban street canyons.”

The study concluded that judicious placement of grass, climbing ivy and other plants in urban canyons can reduce the concentration at street level of NO2 by as much as 40 percent and PM by 60 percent, much more than previously believed. The authors even suggest building plant-covered “green billboards” in these urban canyons to increase the amount of foliage. Trees were also shown to be effective, but only if care is taken to avoid trapping pollutants beneath their crowns.

The authors acknowledge funding from the UK Engineering and Physical Sciences Research Council Sustainable Urban Environment program.

Read more at ScienceDaily:

  • Jin The Ninja

    it’s chemtrails! chemtrails i tell you!
    pollution is the conspiracy of marxist birkenstock eco-homo liberals!
    trees are the demon spawn of the bohemian grove horned god.
    ron paul, ron paul.
    guns! the constitution! america is the best!
    illumanti comin’ for our guns!
    arm the republic- save the day!
    michael bay should make more movies!

    what were we talking about again…? oh yeah trees- gay.

    • The Baffler

      Guns guns guns!

      • Anarchy Pony

        When you say “Guns guns guns!”, that’s not a Robocop reference is it?

        • The Baffler

          Not intentionally. Although Robocop is the greatest of Verhoven’s works.

          • Jin The Ninja

            yes. yes it is. but i still have a place in my heart for ‘total recall’ and ‘ of course the classic known as ‘showgirls.’ in my mind, and i said this a few weeks ago- paul verhoeven is an unsung genius of american cinema. (and who can forget starship troopers!)

  • The Baffler

    Trees! But trees are communist!

    Good, Capitalist cities have menials who hold up concrete replicas of trees for minimum wage.

  • The Friday Knight

    I bet if they did a study on greenery and crime…they would find that crime and violence rates are lower in communities with ample greenery. If you think about it…it’s greenery that gives neighborhoods it’s “plush”, suburb appearance not necessarily the houses.

    • Anarchy Pony

      I imagine that that study probably already exists.

  • BuzzCoastin

    > The authors acknowledge funding from
    the UK Engineering and Physical
    Sciences Research Council Sustainable Urban Environment program.

    hope they publish a paper on how they got funding to state the obvious
    or maybe, just maybe
    the funding had other purposes
    as people cozy into their little cyborg-city niches

    not saying cities should not have more green
    but the present city model is unsustainable
    and the air ain’t the worst part