Noise Pollution

Noise pollution

Noise pollution is a serious threat to the quality of man's environment. Noise, by definition, is over-loud or disturbing sound.Sound levels are measured in decibels (dB). It is a unit for expressing the relative intensity of sound on a scale from 0 to 130.

Noise is unwanted sound and has become a part of urban life and industrial centres in this century. Noise pollution may come from loudspeakers, factories, aeroplanes, moving trains, construction activity or even a radio.

Noise level of 80 decibels or more for more than 8 hours a day increases tension and changes in breathing patterns. Continued exposure to high levels of noise results in fatigue, hearing loss or even total loss of hearing, changes in blood circulation, changes in breathing, etc. Noise pollution above 120 decibels can cause many adverse biochemical changes. Cholesterol levels in the blood and white cell counts increase, besides causing hypertension.

Effects of Noise Pollution

• Even short exposure to noise can produce temporary hearing losses.
• Prolonged exposure to noise can lead to a gradual deterioration of the inner ear and subsequent deafness.
• Constant noise causes the blood vessels and muscles to contract. This causes a gradual loss of hearing, tension, nervousness and psychiatric illness. High intensity sounds emitted by many industries and supersonic aircraft, when continued for long periods of time not only disturb but also permanently damage hearing.
• Noise has harmful effects on non-living materials too. Numerous examples can be cited where old buildings and even new constructions have developed cracks under the stress of explosive sounds.

Sources of Noise

The major sources of noise are

• Use of Television and Radio
• Railways
• Use of loudspeakers
• Industrial activities
• Aircraft

Psychological and physical effects of noise at different decibel levels (db)

Standards and guidelines

Summary of recommended noise exposure limit (World Health Organisation - 1980)

Noise standards (as notified in Environment (Protection) Rules,1986)

The Central Pollution Control Board constituted a Committee on Noise Pollution Control.The Committee recommended noise standards for ambient air and for automobiles, domestic appliances and construction equipments, which were latern otified in Environment(Protection) Rules,1986 as given below:

Note:

• Day time is reckoned in between 6 a.m. and 9 p.m.
• Night time is reckoned in between 9 p.m. and 6 a.m.
• Silence zone is referred as areas upto 100 meters around such premises as hospitals,educational institutions and courts.The Silence zones are to be declared by the Competent Authority. Use of vehicular horns,loudspeakers and bursting of crackers shall be banned in these zones.
• Mixed categories of areas should be declared as one of the four above mentioned categories by the Competent Authority and the corresponding standards shall apply.

Control of Noise Pollution

• A green-belt effectively reduces the noise.
• A 20 foot wide plantation inside the compound protects the house from the noise of vehicular traffic.
• Decibel metres should be installed along highways and in factories to check and control the intensity of noise pollution.
• Specific legislation and regulations should be proposed for designing and operation of machines to include vibration control, sound-proof cabins and sound-absorbing materials.
• In metropolitan areas a green belt of vegetation and open spaces in general may have a great value in noise control as in air purification. It has been seen that plants are efficient absorbers of noise, especially noise of higher frequency. Plants can also absorb aeroplane noise, so a green belt should be planted around airports.

Loud speakers, which have become a part of festivals, weddings and prayers are banned in most places. The playing of loud speakers should be reported immediately to the police.

Source : CPR Environmental Education Centre, Chennai

Related Resources

1. Noise pollution norms
2. Noise Pollution (Control and Regulation) Rules, 2000
3. Authority for implementation of Noise Rules in states
4. Noise Standards for Fire-crackers