my friend, quoting from
http://www.ghasp.org/publications/trees/TreesAndOurAir.html
In urban areas, trees and other vegetation also reduce urban noise,
which has been associated with a number of adverse health effects,
including insomnia, hypertension, and depression. There is also
some indication that chronic noise, such as from nearby freeways,
can lead to increased violence. A well-placed stand of trees can
reduce noise by up to 15 decibels, approximately that provided by a
typical sound barrier.
Now this is about man made noise barriers
http://www.fhwa.dot.gov/environment/keepdown.htm
Noise barriers are solid obstructions built between the highway and
the homes along a highway. They do not completely block all noise
they only reduce overall noise levels. Effective noise barriers
typically reduce noise levels by 5 to 10 decibels (dB), cutting the
loudness of traffic noise by as much as one half. For example, a
barrier which achieves a 10-dB reduction can reduce the sound level
of a typical tractor trailer pass-by to that of an
automobile.
So i will let figures speak for themselves. By the way, this info
took me only 5 minutes to search on the world wide web. So next
time you want to say something, please do a little
research.
