However, the results of surveys show that in the most developed countries complaints
about the arduousness of noise and vibrations are the most common. For example, in Japan
in 1979, complaints from the population about the particular kinds of the contamination
of the environment were listed in the following order:
– noise – 36.6%
– intensive odours – 24.6%
– air pollution – 18.3%
– water pollution – 14.7%
– vibrations – 5.5%
– contamination of the surface of the Earth – 0.3%
– ground settlement – 0.1%
French studies in 1986 have
shown that complaints about noise are even more prevalent. 79.2% of people complained
about excessive noise while only 7.7% complained about air pollution. The results cited
above show that such a serious problem cannot be ignored.
Noise is defined as any unwanted, unpleasant, burdensome or harmful mechanical vibration
of an elastic medium, transmitted by air and affecting the hearing organs and other senses
as well as elements of the human organism. According to the frequency of vibrations the
following types of noise are distinguished:
– infrasound noise, which are inaudible, but can be felt, whose frequency is lower
than 20 Hz,
– audible noise, whose frequency is between 20 and 20000 Hz,
– ultrasound noise, which is inaudible, whose frequency is higher than 20000 Hz.
The term "vibration" is used to describe vibrations which are transmitted by solids rather
than by air.
Noise as a harmful factor has been present around people for many ages. Burdensome and harmful effects of noise have been known and sporadically used for thousands of years (Jericho horns). Never though has noise been so prevalent and burdensome as it is now.
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