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|Year : 1998 | Volume
| Issue : 1 | Page : 3--5
Noise, the most ubiquitous pollutant
Professor of Otolaryngology, General Secretary, IFOS, The Toronto Hospital, University of Toronto, Canada
P W Alberti
Professor of Otolaryngology, General Secretary, IFOS, The Toronto Hospital, University of Toronto
|How to cite this article:|
Alberti P W. Noise, the most ubiquitous pollutant.Noise Health 1998;1:3-5
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Alberti P W. Noise, the most ubiquitous pollutant. Noise Health [serial online] 1998 [cited 2020 Aug 7 ];1:3-5
Available from: http://www.noiseandhealth.org/text.asp?1998/1/1/3/31783
"Noise is the most impertinent of all forms of interruption. It is not only an interruption but also a disruption of thought" from Psychological Observations Arthur Schopenhauer.
I congratulate the publishers and editor for founding this journal, the need for which has been evident for some time. Noise is the most ubiquitous global pollutant, which permeates all aspects of life throughout the inhabited world. Its impact upon hearing, communication, learning and well being is enormous and yet the very breadth of its impact means that it is studied by many disciplines, none of which cover the totality of the topic. The result is that information, particularly inter-disciplinary information is difficult to find and sometimes missed. The topic is sufficiently broad that even the usual abstracting services useful though they are, are frequently inadequate.
It has been recognised for centuries that noise damages hearing and at present it is the greatest single cause of preventable sensorineural hearing loss in the world. It is known that prolonged exposure to workplace noise in excess of 85 dBA will produce some hearing loss; it is known that much of the machinery of warfare produces even higher sound levels than are found in industry. It is known that those working with machinery of all types, not just in manufacturing but in construction, agriculture, mining and other resource industries are at risk of hearing loss from noise. It is estimated that in the United States 30 million people are at risk for hearing loss from excessive exposure to noise - this is 11% of the total population. The numbers at risk in Europe are similar. Although noise was considered an issue peculiar to the developed world, this is now recognised to be untrue. The developing world has even greater problems. The United States is now in a post industrial era with a much smaller proportion of its workforce employed in manufacturing than previously, a much smaller proportion than is found in many of the large developing countries. The United States also has a longer life expectancy therefore has a smaller proportion of its population in the workforce. If this thesis is accepted, it is suggested that perhaps 12% or more of the global population is at risk for hearing loss from noise i.e. well over 600 million people.
There are by now many reports of high noise levels and hearing loss produced by industrial exposure in developing countries, from mines in Africa and India, from textile plants in Asia, automobile assembly plants, the list is ever increasing. There is however need for considerable education of workers and management about the harmful aspects of noise and the benefit of reducing it. The gradual replacement of antiquated and noisy machinery by quieter and more efficient devices increases productivity both because of the greater effectiveness of the machinery and better working conditions. Even where workers know that noise produces hearing loss, they are reluctant to complain, as they were in the West 60 years ago, for fear of losing a job and because they are unaware that anything can be done. There is need for regional and national epidemiological studies to determine the magnitude of the problem and to educate employers, employees and politicians about the nature of the problem and then educate them about what action is required. Gradually countries, even poor ones, such as Kenya, are passing laws about noise control and limits to exposure. If Kenya can so can other countries. I chose the example of Kenya because poor as it is, through the dedicated efforts of 1 or 2 professionals led by Dr Manu D'Cruz sustained political effort has led to great change and this shows the direction of how change can begin. Sustained efforts by professionals can provide results!
Noise in industry does more harm than just to damage hearing. In the workplace even levels which are just low enough not to damage hearing may nevertheless be high enough to interfere with communication, to interfere with the hearing of warning signals and to be stressful. They produce what the late Raymond Hetu described as "an ergonomically extreme condition". Psychologists have shown long ago that productivity improves if workplace noise levels are moderated.
The problem of noise is much greater than industrial hearing loss. City noise levels in all parts of the world are rising particularly in the new mega cities. There were only 2 cities with more than 10 million population in 1959, now there are 14 and within 25 years there will be 28 with the overwhelming majority in the developing world. Sound level studies have been made in cities as far apart as Karachi, Bangkok and Calcutta and all show levels well in excess of what would be considered harmful in the workplace. Indeed, one study in Calcutta found that in a mixed industrial/residential area sound levels only fell below 90 dBA for 4 hours in 24, and sound levels in excess of 100 dB are commonplace in Asian city centres. They result from widespread use of 2 stroke engines, motorcycles and tricycles, the blaring of sound from bazaars and the poor repair of elderly diesel vehicles and the almost ubiquitous blowing of horns. Such sound levels interfere with communication, learning and the well being of people exposed to it. Many live right in the noise. Thus, social noise presents a health hazard in terms of well being.
Noise interferes with education. Children learn less well in a noisy than a quiet classroom as has been shown in reasonably controlled trials; teachers subjected to high background levels of noise as for example from adjacent highways, repeated jet over flying or proximity of railroads, tend to speak less to preserve their voices and the children learn to shut out extraneous sounds and very quickly their instruction as well.
What can be done? The future is interesting and challenging. There is excellent research of the impact of noise on animals both on the auditory system and on the cochlea itself. It has long been known that noise damages hair cells, and now both the ultra structural mechanism and even now the biochemical changes which take place are being elucidated and with it comes the promise of chemical preventative measures. Study of how noise is processed by the brain has shown that there is in fact a toughening mechanism mediated by feedback loops whereby prior exposure to low level of sounds toughen the ears and hearing loss may not be as great as predicted.
On the other hand the interaction of noise with other ototoxic agents is only just being explored and in particular the interaction between noise and certain chemical solvents such as toluene and petro-chemicals, where the effect may be synergistic. Animal models are just being developed and much more epidemiological work is needed.
There is also need for much greater study of individual noise exposure. Most large scale surveys have relied on noise levels in a workplace without actually measuring noise received by individual workers, something which is now possible with modern dosimeters. The huge individual variation in hearing levels, attributed to sound damage may in fact be in part related to the failure to take into account actual noise levels received by the ear and by synergistic effect of other ototoxic exposures.
There is need for behavioural research on how best to make people aware of the problem of noise, which is probably best done nation by nation because solutions do not easily transcend national boundaries. There is certainly need for a great deal of education for the public and politicians about the physical, psychological and social problems related to noise and of the means of coping with it. There is need to bring together sources of information about legislation in different countries and about solutions that have been effective and about studies which are being undertaken. In short, there is need for an international network about noise and this journal hopefully will form an integral link in such an information web.
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