Noise, commonly defined as unwanted sound, is another environmental pollutant. Particularly in congested urban areas, the noise produced as a byproduct of our advancing technology causes physical and psychological harm, and detracts from the quality of life for those who are exposed to it.
Unlike the eye, the ear has no lid; therefore noise penetrates without protection. Loud noises instinctively signal danger to any organism with a hearing mechanism, including human beings. In response, heartbeat and respiration accelerate, blood vessels constrict, the skin pales, and muscles tense. In fact, there is a general increase in functioning brought about by the flow of adrenaline released in response to fear, and some of these responses persist even longer than the noise, occasionally as long as thirty minutes after the sound has ceased.
Because noise is unavoidable in a complex, industrial society, we are constantly responding in the same ways that we would respond to danger. Recently, researchers have concluded that noise and our response may be much more than an annoyance. It may be a serious threat to physical and psychological health and well-being, causing damage not only to the ear and brain but also to the heart and stomach. We have long known that hearing loss is America’s number-one nonfatal health problem, but now we are learning that some of us with heart disease and ulcers may be victims of noise as well. In addition, the psychic effect of noise is very important. Nervousness, irritability, tension, and anxiety increase and affect the quality of rest during sleep, and the efficiency of activities during waking hours.