Source-level Control:
i. Substitution of highly noise-generating machines with quieter machines, usage of vibration-isolated mountings, and reduction of the external surface of vibrating parts helps in noise reduction at source.
ii. Using a muffler and dampening the vibrating surface subsides the noise pollution at the source.
iii. Enclosing the noise-generating source in a box or in a glass cover can reduce the source-generated noise transmission to its surrounding.
Path level control through modification: Modification of the path along which the noise is propagated is highly effective in noise control. Tunnel construction with the help of barrier shields, hard boards, and plywood to modify the path of noise transmission, and intense architectural planning by using acoustic materials on walls, ceilings, and doors to absorb sound highly reduce the reverberation of noise.
Receiver level control: In spite of the engineering methods, some industrial noise can’t be silenced and so the receiver should wear ‘earplugs’ which can protect the receiver against noise pollution. Job rotation of the worker can restrict the length of exposure to potentially hazardous noise levels.
Buffer zone by Green Cover: Tree are capable of absorbing enormous amount of noise. Planting of Ashoka and Neem tree along the highways, around industries, and jet ports play an important role in absorbing noise.
Miscellaneous control methods:
- Banning the use of horns, loudspeakers, and bursting crackers in and around educational institutions, hospitals, wildlife sanctuaries, and national parks.
- Imposing huge fines on vehicles generating noise (Environmental Protection Act, 1986 and Motor Vehicles Act, 1988).