Introduction
Noise is defined as unwanted sound and it is an irritant and a source of stress. Most of the noise one hears originates from human activities.
How is Sound Measured?
Sound is measured in decibels (dB). Decibels are named in honour of Alexander Graham Bell. Decibels are different from other familiar scales of measurement. It is not a linear, but a logarithmic scale. For example, if a sound is 80 decibels, and we add another 10 decibels, the sound will be ten times more intense. When the sound level reaches 140 dB, we will start feeling pain in the ears. However, long exposure to noise even at 85 dB can cause hearing loss. Apart from loudness, the frequency or pitch of the noise also determines whether it is harmful or not. A modified scale called decibel-A (dbA) takes pitch into account.
Hearing loss begins if a person is exposed more than 8 hours a day to a noise level of 80 - 90 dbA. A level of 140 dbA is painful and 180 dbA could Kill.
The main Sources of Noise Pollution -
The main sources of Noise pollution are:
- Transport sector: aircraft, trains, trucks, tractors, cars, three-wheelers, and motorcycles contribute the maximum noise.
- Industrial and construction machinery: Factory equipment, generators, pile drivers, pneumatic drills, road rollers, and similar machinery.
- Special events: High-volume sound from loudspeakers during pop music performances, marriage receptions, religious festivals, public meetings, etc.
Noise pollution is increasing in industrial societies and in cities everywhere.
Types of Noise Pollution -
Noise pollution can be classified into the following three types:
1. Transport Noise - Noise produced by different modes of transportation is called transport noise. This can be divided into the following three types:
- Road Traffic Noise - Road traffic noise is produced by different vehicles on the road such as trucks, buses, cars etc. Heavy diesel-engined trucks create maximum noise on the road. Noise is particularly generated by the horns and types of these vehicles. 70 dB is the allowed noise level for road traffic noise near residential areas.
- Aircraft Noise - Aircraft noise is produced by aircraft engines that fly overhead or take off and land at airports.
- Rail traffic Noise - Rail traffic noise pollution caused by trains is generally of lower frequency than street vehicles. This is because most railway tracks run through rural areas. But, buildings near railway tracks are exposed to noise pollution due to rail traffic noise. Nowadays, diesel and all-electric locomotives are used have greatly decreased rail traffic noise.
2. Occupational Noise
This type of noise pollution is produced mainly in industries by
- Industrial machines
- Product processing techniques
- Welding processes
- Vacuum cleaners
- Washing machines etc.
This affects the industrial workers to a great extent. It may affect the hearing activities of many workers. It causes a loss of concentration in workers. Sometimes, serious accidents can occur due to loss of concentration.
3. Neighbourhood Noise -
This type of noise pollution mainly affects the general public. Noise such as loud TV, radio set noise, shouts by vendors, loudspeakers, alarms, domestic noises, disco music etc. are examples of neighbourhood noises.
Effects of Noise Pollution -
Noise pollution is the pollution created by loud noises which adversely affect the surroundings. Noise pollution has various effects and some of them are -
1. Irritation - Unwanted sound causes irritation and disturbance to the listener. Loud noise causes a sensation of pain in the ear. Excess noise causes tension in our daily life. If the noise level is 65 dB, then we can hear the conversation at a distance of 1 metre. A noise level of 125dB causes pain in the ear. A noise level of 150 dB is much more harmful to the human ear.
2. Loss of hearing - Listening to noise for a longer period of time badly affects the hearing ability. It may sometimes cause loss of hearing.
3. Physiological Effects - Unwanted sound is harmful to our health. It causes high blood pressure. Heart-beat rate, pulse rate and breathing are also affected due to unwanted sound.
4. Work performance failure - Noise causes pain in the ears, feeling of tiredness and loss of concentration. It affects the nervous system. A person cannot work properly due to noise pollution. Noise pollution in industries decreases the efficiency of workers. People cannot sleep properly due to noise. This decreases their presence of mind in different activities.
5. Sleeping Disorders - Excessive noise affects our sleeping patterns which may lead to extreme health issues.
6. Loss of Concentration - Unwanted noise distracts the human mind and it difficult to concentrate or focus on work or study.
Control of Noise Pollution -
Noise pollution can easily be controlled by following Steps.
1. Control of Transport noise -
- Noise-producing industries, railway stations, airports etc should be located far away from residential areas.
- Planting trees along the roads and railway tracks helps in controlling noise pollution. Plants can absorb high-frequency sound waves.
- Every vehicle should be maintained and serviced from time to time to prevent the noisy engine.
- The horns of vehicles should not be blown unnecessarily and fixed of silencers to automobiles.
2. Control of Occupational noise -
- Use of earplugs, earmuffs and other protection equipment.
- There should be routine changes in the duty of workers. Due to this, a single worker will not be exposed to noise pollution for a longer period of time.
- When the noise is produced, some barriers can be installed between the source and the receiver in industries.
- The bursting of crackers unnecessarily should be avoided.
- Sound sources for different machines can be enclosed in a room.
3. Control of domestic noise -
- We should avoid playing speakers, radios, and television loudly at home.
- Using carpets or other absorbing materials.
- Advanced machines which produce less noise can be used at home.
- We should not use loudspeakers, TV sets or radios at high volumes, especially at night. Even in day times, they should be used at low volumes.
- We should keep checking the surrounding noise levels and limit the sounds that we produce.
Frequently Asked Questions (FAQs) -
Question - How is sound measured?
Answer - The Loudness of sound is measured in decibels (dB). Decibels are named in honour of Alexander Graham Bell. Decibels are different from other familiar scales of measurement. It is not linear, but a logarithmic scale relates the intensity of a pressure wave to a normal or standard pressure. For example, if a sound is 80 decibels, and we add another 10 decibels, the sound will be ten times more intense.
Question - How many decibels are defined as noise Pollution?
Answer - The World Health Organization (WHO) defines noise above 65 decibels (dB) as noise pollution. To be precise, long exposure to noise even at 85 dB can cause hearing loss.
Question - What are the different types of Noise pollution?
Answer - Noise pollution can be classified into the following three types:
- Transport Noise,
- Occupational Noise,
- Neighbourhood Noise
Question - What are the three main sources of Noise Pollution?
Answer - Noise pollution can come from different sources, but three of the most damaging sources are-
- Transport sector: aircraft, trains, trucks, tractors, cars, three-wheelers, and motorcycles contribute the maximum noise.
- Industrial and construction machinery: Factory equipment, generators, pile drivers, pneumatic drills, road rollers, and similar machinery.
- Special events: High-volume sound from loudspeakers during pop music performances, marriage receptions, religious festivals, public meetings, etc.
Noise pollution is increasing in industrial societies and in cities everywhere.
Question - What are the effects of noise pollution?
Answer - Noise pollution is the pollution created by loud noises which adversely affect the lives of millions of people and wildlife. Problems related to noise pollution include irritation, high blood pressure, sleep disruption, Loss of concentration and hearing loss.
Question - What are the control measures against noise pollution?
Answer - Producing less noise is the best method of reducing this pollution. Almost all machinery can be redesigned to reduce noise. Another way is to provide shields and noise-absorbing material. Earplugs and earphones can shield the receiver from noise.
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