According to a recent fact sheet on occupational and community noise issued by the World Health Organization (WHO), prolonged or excessive exposure to noise, whether in the community or at work, can cause serious permanent medical conditions like hypertension and ischaemic heart disease. Noise can also adversely affect performance of reading, attentiveness, problem solving and memory. The effect of noise on the human system can range from annoyance to problems with communicating to actual psycho-physiological effects. Noise above 80 decibels may also increase aggressive behavior.

The WHO report also pointed out that in the developed world, noise related hearing impairment is mostly restricted to the work environment. However, in developing nations, not only are the industrial noise levels higher, but the problem is worsened with the high levels of community noise.

Industrial workers exposed to noise often turn up the volume of radios after work, but in the morning, turn it down, as they find it too high. This is one example of temporary impairment. However, if the exposure is continuous, the condition can become permanent in 6 to 12 months in units where noise levels are above the recommended units. The WHO estimated that it is ten times less expensive to make the noise generating processes quieter than to make barriers to prevent noise pollution.

Source: Noise above 80 decibels may increase aggressive behavior, Times of India, Mumbai, 2001 March 6.