Noise Pollution

A recent term used to suggest the destructive effects of excessive sound, usually based on properties of loudness and irritation. Some adverse effects of noise may be physiological (see boilermaker's disease, hearing loss, threshold shift), others psychological (anxiety, nervousness, loss of sleep, etc.) and still others communicational (see jet pause, Speech Interference Level). Since physiological damage has been well researched, remedies are better known and are beginning to be adopted, for instance, in damage-risk criteria for industrial noise. See: Occupational Deafness.

Although there is evidence that exposure to certain modern environmental sounds may pose a hearing risk (see presbycusis, sociocusis), it has been more difficult to set limits on environmental sounds, though many countries and cities have attempted to do so, particularly for technological noises such as automobiles, air conditioners, etc. Composite zoning along acoustic lines is employed in Japan, Switzerland, parts of Australia and in Scandinavia. In this case, the general Ambient Noise Level is monitored in order to ensure that the level does not exceed set limits more than 10% of the time. In other parts of Europe and North America, limits are set for particular noisy sounds and these are checked wherever they may occur.

The problem of noise pollution is complex and it is difficult as yet to know whether noise pollution in the community is being brought under effective control. Comparisons between recent surveys suggest that the Ambient Noise Level of cities is continuing to rise, perhaps by as much as 0.5 dB per year.

For various noise measurement systems, see: Community Noise Equivalent Level, Composite Noise Rating, Equivalent Energy Level, Noise and Number Index, Noise Exposure Forecast, Noise Criterion, Noise Level, Noise Pollution Level, Noise Rating, Perceived Noise Level, Traffic Noise Index. See also: Decibel, Sound Level, Sound Level Meter, Sound Pressure Level, World Soundscape Project.

The psychosocial effects of noise pollution have scarcely been considered in noise abatement legislation, mainly because they are less easily quantifiable. However, such effects should not be neglected, and noise pollution will not be under control until they too have been significantly reduced.

For a contrasting attitude towards the problem in terms of the soundscape, see sound intrusion, sound pollution. Compare: Silence.