Have you ever been in a large room full of people talking and you feel like you have to yell so the person next to you can hear? Did you feel overwhelmed by the amount of noise and left the room with a ringing in your ears? This is due to the echo created by all of the people’s voices or music bouncing off the walls, ceilings, floors and other hard objects in the room.

Studies have shown that the leaves of plants attenuate sound by reflecting, refracting and absorbing acoustic energy in small amounts. The amount of noise reduction is proportional to the number of plants that are present in a room. Green walls contain such a large number of plants that the acoustics of a room can be substantially improved.

Plants are sometimes used in buildings for their acoustical benefit alone. In Germany a green concert hall was constructed which incorporated many plants. The high density resulted in such a good acoustic quality that the German Broadcasting Station relocated to use the room for news casting.

Plants and trees have been used for years as barriers against traffic and other urban noise pollution. Green walls built on the exteriors of buildings will do the same. They insulate against noise, vibrations and reduce sound penetration. In addition they help to absorb the echo bouncing off buildings and dampen the noise pollution of modern cities.