Ours is an age in which scientists as well as ordinary people are increasingly concerned about the harmful effects of pollution. Day in and day out, all over the world, the atmosphere around us is exposed to the bombardment of chemical wastes, obnoxious gases and other undesirable products making the very act of breathing, so necessary to sustain human life, increasingly difficult and finally impossible.

But it is now beginning to be universally acknowledged that loud noise is perhaps the most pervasive kind of pollution. Research has shown that it not only causes injury to the ears but also changes one’s mood and decreases learning ability. Some people believe that it even increases the blood pressure. It does not take the ear-piercing clatter of a jackhammer for a city dweller to experience, every day, enough noise, to cause permanent hearing loss. The screeching sounds of traffic, the staccato of pneumatic drills, the deafening roar of aeroplanes flying low, and even loud music, and announcements from loudspeakers and televisions, are enough, to exceed the maximum noise level that the human ear can receive, without injury.

Till now not much success has been achieved in the matter of noise reduction mainly due to the lack of a systematic approach. A few years ago The United States Environmental Protection Agency had launched an ambitious 25 million dollar programme to curb noise pollution. The Federal Aviation Administration was able to enforce a rule to make aeroplanes cut down noise levels by half within 2 km of taking off and landing at major airports. Even though New York City adopted America’s first anti-noise code some years ago by imposing heavy fines for violations, some people feel that taxi-drivers still depend more on their squeaky horns than on their brakes for negotiating their way through heavy traffic.

It is, however, generally accepted that unless all people cooperate in the task of controlling noise, the problem would remain insurmountable. Indeed, scientists feel that most damaging noises are within the power of ordinary people to control simply by using a little common sense. Take, for example, stereo head phones-devices, that can cause injury to the eardrums, even while delivering entertaining music, because of the fluctuation in sound levels. A study by a prominent otolaryngologist (a doctor specialising in the ear, nose and throat diseases) in the University Hospital in Iowa City in the United States revealed that teenagers, who used stereo head phones for three hours continuously suffered tempo­rary hearing loss. These devices proved to be extremely harmful when played at a noise level of 100 decibels or more, which is comparable to the noise of a chain saw. It is, therefore, suggested by scientists that people should not turn them up above a normal conversational level. People addicted to stereo headphones should perhaps remember this advice while driving a car, reading a book or waiting for a bus! Similarly the damage that could be caused to the eardrums by the sound emanating from the ubiquitous cell phone which people are holding close to the ear for a major portion of the day is of concern to doctors.

It is now known that stunning or sudden explosions can result in deafness because of the rupture of the ear drum. But in such cases, hearing can be partially restored by surgery. On the other hand, deafness caused due to sustained environmental noise is irreversible. As the sounds enter into the inner area of the ear, they wave hair cells back and forth causing them to release a chemical transmitter to the nerve fibres that carry auditory messages to the brain.

It is, however, admitted by neurobiologists that a few missing hair cells will not damage hearing permanently. But a few lost every other day will gradually lead to a noticeable hearing problem. Once such a stage sets in, it is too late to do anything but some precautions can be taken. Ear plugs and muffs which reduce noise by as much as 25 decibels can make the difference between dangerous and safe exposure. Similarly, separating periods of exposure to intense noise, with at least a day of relative quiet, can allow stunned hair cells to recover. Thus, if you have to cut wood with a chain saw you are advised to do so for an hour on one Sunday and another hour the following Sunday, rather than for two hours on the same Sunday at one stretch. This would allow the hair cells sufficient relaxation time between bouts of unhealthy exposure to harmful noise levels.

The most important question is: What effect does noise have on the human system? There is evidence to show that it certainly makes people angry. It is quite likely that noise elevates the blood pressure though concrete evidence is necessary to reach a definite conclusion. Scientists, however, do agree that noise does have some kind of an unhealthy impact on the brain. Children studying in schools situated on noisy streets get lower marks than their counterparts in quiet schools in secluded areas. Similarly, two British psychologists found that suburban traffic at about 46 decibels (similar to the sound of a refrigerator) impairs sleep. When the amount of noise entering the subjectsbedrooms was reduced by 5 decibels (comparable to the level of soft speech), their brain indicated an increase in low frequency, high amplitude delta waves, which are indicative of deep sleep. One researcher, in the Medical College of South Carolina, found during the course of several animal experiments that 65 decibels of sound sustained for 24 hours (comparable to the sound produced by an air conditioner) were found to somehow damage the brain stem. Scientists are naturally curious to know whether similar damage occurs in humans and, if so, when injury to the brain begins. They would like to investigate whether damage to the brain is independent of injury to the ear.

Obviously then, till such time as scientists are able to accurately calculate the level of sound that the human brain can take without harmful effects, the best course to follow would be to reduce our exposure to noise as much as possible. But, exposed as all of us are, in this technology-oriented world of today, to the sounds of jet aircraft, the hooting sounds of horns, the screeching noise of brakes and so on, perhaps, this is easier said than done. But what we all could do is to observe simple precautions like protecting our ears properly when the occasion demands.

Despite all the warnings indicated in this article, one must realise that even though loud music by direct impact as noise is indeed harmful, soft and soothing music is not only harmless but also beneficial.

. Shakespeare makes Julius Caesar tell

Antony, that one of the reasons why Cassius could not be trusted was because he did not like music.

And in the Merchant of Venice, Lorenzo observes

“The man that hath no music in himself

Nor is not moved with concord of sweet sounds

It fit for treasons, stratagems and spoils

The motions of his spirit are dull as night

And his affections dark as Erebus

Let no such man be trusted”.

 Poets believe that music can sing the savageness out of a bear; one does not have to be a poet a lover, to respond in ecstasy to the soothing effects of melodious music; indeed all human beings, except a perverted few, enjoy listening to music which is indeed the food of love.


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