This article throws light upon the five major sources of noise pollution. The sources are: 1. Noise generated from Wars between Countries 2. Neighbourhood Noise 3. Traffic Noise 4. Occupational Noise 5. Noise at Religious and Cultural Functions.
Noise Pollution: Source # 1. Noise generated from Wars between Countries:
A survey by the US Federal Council of Science and Technology has revealed that noise is a technology-generated problem and that the overall loudness of environmental noise doubles every ten years in pace with our social and industrial progress. This geometric growth of ambient noise level could have very serious consequences in view of the accelerating pace of technological growth.
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Since noise is so closely related to technological and industrial growth it follows that the problem of noise pollution is no longer confined to the technologically advanced Western Countries. With rapid industrialization and urbanization, many Third-World countries have fallen victims to the problems of noise pollution.
In Table 7, the percentage of people disturbed by various kinds of noise in Pattaya (Thailand). A comparison of noise levels in Bangkok (Thailand) with the Minnesota Standards is given (Thanh et al 1978) in Table 12. It is evident from this table that the noise levels in Bangkok are quite high in comparison with the prescribed standards.
Industrial growth is not the only factor contributing to noise pollution in the Third-World nations. Many of these countries – especially India – are noise loving nations in the sense that on almost every occasion from birth to death loud noise (i.e., music) is a part of their culture. Religious and cultural functions also contribute to the problem of noise pollution, as discussed below in India and other countries.
Noise Pollution: Source # 2. Neighbourhood Noise:
It is well known that noise in Indian cities is growing fast and beyond human tolerance. The gravity of the situation can be judged to some extent from the fact that, compared to the standards of WHO (World Health Organisation) and BIS (Bureau of Indian Standards), the noise levels in our cities are much too high.
In large cities, they range from 90 to 100 dB (A) while in cities like Calcutta and Bombay, the noise levels may even cross Noise level surveys have been conducted in several cities of India The Acoustic Division of National Physical Laboratory (New Delhi) found that the average noise level of our cities is quite high. Similar studies were conducted by the AIIMS (All India Institute of Medical Sciences).
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We discuss in this section the so-called “neighbourhood noise” This includes noise disturbance that may be present in the home, and in public places of entertainment or in the open air, but excludes industrial, road traffic and aircraft noise. Noise in the home impinges upon domestic life, and its main sources are loud TV and radio sets, parties, children playing, domestic animals, motor cars, motorcycles, etc.
Noise in open-air spaces is usually a transient or periodic nuisance depending upon the various activities that are taking place. Noise from a football ground, for example, can reach a level of 110 dB(A) when the goal is scored, but it occurs only when the match is being played. Athletics meetings, carnivals, fairs and open-air pop concerts may all be sources of noise in local neighborhoods.
The increasing use of loudspeakers and amplified music can cause complaints about high noise levels in the neighbourhood.
Even indoor places of entertainment such as dance halls and discotheques can cause noise nuisance to nearby residents, especially late in the evening. A growing number of complaints regarding the neighbourhood noise arise from the activities of the construction industry, e.g., demolition, building construction, road construction work, etc.
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Unfortunately, there are very few studies on the extent of neighbourhood noise in India. But the present author and his associate conducted a detailed survey of noise levels in commercial areas (Tiwari and Ali, 1988B) and some commercial banks (Tiwari and Ali, 1988D) of Rourkela.
These authors studied also the effects of height, type and separation of houses (Tiwari and Ah, 1988C) on the noise levels in the residential localities of Rourkela.
Noise Pollution: Source # 3. Traffic Noise:
Noise from road vehicles produces disturbance to more people than from any other source of noise. Moreover, traffic noise has been increasing over the least few decades due to increased density of road traffic. Speed of traffic is one of the most important causes of noise on the roads. Modern road developments encourage higher speeds which, in turn, lead to greater noise volume.
In contrast to high-level noise in industrial situations, the traffic noise may not cause damage to the physical mechanism of the ear, because of its relatively low levels. However, traffic noise has other insidious effects. For example, continual exposure to traffic noise may accelerate the age-induced deafness.
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Traffic noise certainly disturbs the quality of sleep and, in a few individuals, it may lead to insomnia. At the very least, traffic noise disrupts relaxation and enjoyment of life in the home, and reduces the pleasure derived from conversation listening to the radio and watching the TV.
Most of the studies of noise levels in Indian cities deal with the traffic noise. Recently the present author, for example, conducted a survey (Tiwari and Ali 1988A) of road traffic noise in Rourkela. This survey showed that the traffic noise levels in Rourkela ranged from 62.8 to 110.4 dB(A) and averaged at 79 9 dB(A).
Similar studies by Singh (1984) showed that the average noise level is 90 dB(A) in New Delhi and 95 dB(A) in Bombay.
Studies conducted by the All India Institute of Medical Sciences reported that the average noise levels in Delhi, Bombay and Calcutta were around 95 dB (A), and that these noise levels never fell below 60 dB(A).
Noise levels in different cities have been studied by the Indian Council for Medical Research (ICMR) for South India (Anon, 1979), Industrial Toxicology Research Centre (ITRC) for Luck- now (Gupta et al., 1984), Mukhopadhya and Ramanathan (1967) for Calcutta and Society for Clean Environment (SOCLEEN) for Bombay (Gupta et al., 1984).
Noise Pollution: Source # 4. Occupational Noise:
Occupational and road traffic noise are the two major sources of noise that affect millions of people. Broadly speaking, the occupational noise is largely produced by industrial machines and processes.
But also included in this category is the increasing noise produced in the home from washing machines, spin dryers, food blenders and vacuum cleaners. In industry, on the other hand, workers are subjected to noise for periods up to 8 hours per day and 6 days per week.
Some industrial processes are much noisier than others, but it is known that permanent hearing damage is often found in connection with weaving, ship-building, boiler-making, forging, pressing and blasting operations.
We have collected in Table 13 the typical occupational noise levels in the domestic and industrial situations. On the other hand, minimum, maximum and average values of typical noise levels found in some important industries are given in Table 14.
Industrial noise is a complex phenomenon. It varies with the design, direction, of movement of working parts, and the method of mounting of machines. The noise is often produced in three stages.
There is an initial disturbance at the point of origin of the sound; followed by amplification, often caused by the resonance of the machine parts, the workplace or the floor; and finally radiation of the sound to the surrounding environment. The specific noise produced by any one machine is often a combination of these three stages.
There are several reasons why the consideration of noise is important in industry. In the first place, excessive noise causes hearing loss in the workers.
Secondly, it has an adverse effect on the efficiency of workers. Lastly, workers don’t like high levels of noise as they are distracted and annoyed by them. Unfortunately, the expansion of industries and the development of high speed machines for increased production have led to uncontrolled noise of increased intensity and frequency.
There are many studies in India on various aspects of noise pollution in Industries. The present author has conducted a detailed survey of noise levels (Ali and Tiwari, 1989) in some small-scale industries of Rourkela. The results of various Indian investigations on the industrial noise are summarised in Table 15.
We note from this table that, compared to the 90 dB(A) limit for 8-hour daily exposure, the noise levels in most Indian industries are quite high, and that the workers should be provided with some form of hearing protection.
Noise Pollution: Source # 5. Noise at Religious and Cultural Functions:
As a nation, India is an excellent example of unity in diversity in the sense that the followers of all major religions of the world are to be found in India. In fact, some of the major world religions (e.g., Hinduism, Buddhism and Jainism) had their origins in India. Besides religions, India is also the home of many different types of cultures, languages, customs, etc.
Few other countries can boast of such a diversity and variety in their populations. But an undesirable side-effect of our religious and cultural diversity is that even religion and culture are aggravating the problem of noise pollution in India with the increasing use of loudspeakers and amplified music at all religious and cultural functions.
India appears to be a noise-loving nation. On every occasion, from birth to death, loud music has become a part of our culture. Almost all religious festivals create noise nuisance for the neighbours. Some religious functions, e.g., Bhagwati Jagaran, continue throughout the night, and loudspeakers are invariably used at such functions.
A survey of noise levels at various religious and cultural functions in Lucknow was conducted by Lai (1984). His results are summarised in Table 16. A similar survey for the noise levels at various locations in Bombay during Ganeshotsav (the festival of Lord Ganesh) was conducted by the Society for Clean Environment (SOCLEEN, 1987).
The noise levels in Bombay during this festival were found to vary from 85 to 110 dB(A). Very recently the present author conducted a survey of noise levels in Rourkela (Tiwari and Ali, 1989B) during the religious festival “Durga Puja”. The noise levels during this festival were found to vary from 71.4 to 99.6 dB(A), and averaged at 85.1 dB(A).
