An epidemic of man-made deafness may be threatening the world. The World Health Organization estimates that 360 million people worldwide already have moderate/profound hearing loss with another 1.1 billion people at risk. In the UK 11 million people- – one in six – have some form of hearing loss. This proportion could rise to one in five people by 2035.
It has long been known that noise exposure during work, for example among stonemasons and miners, can cause hearing loss. There is no mandated safe noise exposure for the public anywhere in the world. Dr. Daniel Fink, in a paper presented to the Institute for Noise Control Engineering meeting in Providence, RI (USA) on 14 June 2016, discussed the fact that 85 decibels (dBA), widely thought safe for the public, is an ‘industrial strength’ occupational noise exposure standard. (‘Normal’ conversation is around 60 dB while noise from a jet plane taking off 300m away is about 100 dB, or 16 times as loud – the scale is logarithmic, not arithmetic.)
Because little research has been done on noise and hearing loss in normal life, the work standard has been thought safe for the general public. This is almost certainly wrong for two reasons. First, 85 dBA exposure will cause hearing loss in at least 15% of workers exposed to this noise level during their working lives. Second, noise unlike other workplace pollutants, continues outside the workplace. The U.S. Environmental Protection Agency adjusted the 85 dBA occupational noise exposure level for the additional exposure time – 24 hours a day instead of 8 hours, 365 days a year instead of 240 days at work- to come up with 70 decibels (unweighted) average as the safe environmental noise exposure level to prevent hearing loss.
Dr. Fink writes: ‘Noise exposure…causes auditory damage. Hearing loss is not part of normal physiological aging. In quieter primitive societies, auditory acuity is preserved into old age.’ He draws useful analogies between tooth loss and hearing loss. Both used to be accepted as a ‘normal’ part of ageing, so that by their mid-60s many people were almost toothless. Today, thanks to better dental care most older people keep their teeth. Dentures work but natural teeth work better. Similarly, needing hearing aids in old age is not normal either. And hearing aids are no substitute for preserved hearing. Hearing aids do not correct hearing in the same way that glasses correct faulty vision, because hearing loss involves irreparable nerve and sensory organ damage in the inner ear.
The U.S. Center for Disease Control and Prevention on 16 May 2016 recommended only 70 dB average noise exposure for the public with only one hour noise exposure at 85 dB. This recommendation, as it becomes widely known, should revolutionise overall attitudes towards noise. Noise is like secondhand tobacco smoke: not just a nuisance but a major health hazard causing hearing loss, tinnitus and many other health problems.
(A fuller version of this with supporting footnotes is available on request.)