Green Muffler is a technique of reducing noise pollution by planting 4-6 rows around the populated areas or noisy places like along roadsides, industrial areas, societies near highways, etc. so that dense trees reduce noise pollution as they filter out the noise and obstruct it reaching the citizens.
It is also a device for decreasing the amount of noise emitted by the exhaust of an internal combustion engine.
Under this scheme Ashoka and Neem plants are planted near the house or resident localities to reduce noise pollution.
Do you know why trees are known as noise buffers?
- They control noise pollution. Even urban noises are muffled by trees just like stone walls.
- An advantage of using plants as noise blockers is that they absorb sounds best in the high frequencies that people find it annoying.
- Evergreen shrubs that too with broader leaves provide year round noise protection so, they are best to plant. Trees absorb sound waves with their branches and foliage.
- Plant trees with no space or less space to reduce noise pollution.
- In fact soft ground is an efficient noise absorber. So, avoid hard surfaces to plant trees. Also, cultivate the ground before planting and adding organic matter to the surface of the soil may also help to reduce noise when vegetations will be established.
According to USDA National Agro forestry Center a properly designed buffer of trees and shrubs can reduce noise by about 10 decibels or about 50% as perceived by the human ear.
In most internal combustion engines, mufflers are installed within the exhaust system. It is designed in such a way to reduce the loudness of the sound pressure, which was created by the engine by way of acoustic quieting. Most of the sound pressure, which is produced by the engine is emanating out of the vehicle by using the same piping as used by the silent exhaust gases absorbed by a series of passages and the chambers lined with roving, fibreglass insulation or resonating chambers harmonically tuned to cause destructive interference wherein opposite sound waves cancel each other out. And so the technique to control noise is known as muffler in an engine and to control noise pollution with the help of planting trees is Green Muffler.
The Cabinet Committee on Economic Affairs has approved a proposal of the Ministry of Environment and Forests for a National Mission for a Green India (GIM) as a Centrally Sponsored Scheme which is envisaged in 12th Plan. The objective of the mission includes increase forest or tree cover, improves quality of the forest, improve ecosystem services like biodiversity, hydrological services, increase forest based livelihood income of households, living in and around the forest, etc.