Noise pollution is rapidly joining air and water pollution as an environmental problem of major concern. The diverse effects of noise range from deafness caused by years of exposure to very loud industrial noise to the mere annoyance caused by a dripping faucet or a squawking automobile horn.
It is well established that substantial hearing losses are found among experienced chippers, drop forge and paper machine operators, and boiler makers—all operators of machines that produce very loud noises. It has been conclusively demonstrated by hearing tests and measurement of noise levels and duration of exposure that employees exposed to such noises will sustain hearing impairment, unless protected by wearing well-fitting ear protectors.
Almost all of these studies have dealt with continuous or relatively steady noises. By relating such exposure to observed hearing losses it has become possible to predict the combination of noise intensity, duration, and type (damage risk criteria)