Noise pollution is a disturbance to the human environment that is escalating at such a high rate that it will become a major threat to the quality of human lives. Noises in all areas, especially in urban areas, have been increasing rapidly. Poor urban planning gives rise to noise pollution
Sources of noise pollution
The main source of noise pollution is transportation systems especially motor vehicle. The other sources are aircraft noise and rail noise. Besides transportation noise, other sources are office equipment, factory machinery, appliances, power tools, lighting and audio entertainment systems. Construction equipment also produces noise pollution.
Effects of noise pollution
Due to heavy industrialization, exposure of high level of noise gives rise to stress factor in modern life. It may leads to many hazards.
The effect of noise on health depends on both, loudness and frequency. Any source producing sound levels of more than 80 to 90 db (decibel) for more than eight hours is harmful to human ear.
Frequency of sound is denoted by Hertz (Hz). Human ear can hear frequencies between 20 to 20,000 Hz. Effect of noise on human health depends on i) quality ii) duration iii) sensitivity of the individual the noise pollution produces the following three main effects:
i) Psychological effect
Noise leads to emotional disturbances, however, are difficult to measure. Irritating noise at work place reduces concentration efficiency and working capacity.
ii) Masking effect
Masking noise prevents the ear from registering other important sounds and signals. These effects change the balance in predator /prey detection, by disturbing and interfering the sounds of communications especially during reproduction time period and loss of hearing.
iii) Physiological effect
• Auditory fatigue (when level of noise ranges from 85-90 db)
• Deafness (repeated exposure to noise level > 90 db)
b) Non auditory
• Annoyance (listens dislike the noise content)
• Efficiency (noise pollution decreases efficiency of working)
• General changes in body (high blood pressure, fatigue, hypertension, tetanus)
Control of noise pollution
Noise pollution can be controlled by reducing noise at source. Making a change in design and operation of machines, vibration control, by using sound absorbing materials, can reduce noise pollution.
It can also be reduced by prescribing noise limits for vehicular traffic and planning industrial establishments, amusement areas, residential colonies and hospitals to make them noise proof. The other control methods of noise pollution are:
1. Locate the building as far as possible from noise source.
2. Trees like ashok, neem, coconut etc. can be planted to provide some absorption of sound.
3. Government has already passed the "Noise Pollution Control Act" to meet the special Indian condition. Laws should be made for controlling noise hazards at city level.
4. People can be educated through radio, TV, street play etc. about noise pollution.