The intensity of sound
is measured in decibels (dB) in a scale that ranges from 0 dB (the faintset sound
the human ear can detect)
to more than 180 dB the noise at a rocket launchpad). Because the decibel scale
is lgarithmic, the intessity of noise increase thenfold with each 10-dB increase.
Thus, 20 dB has ten times the intensity of 10 dB, while 30 dB is 100 times as
intense as 10 dB. A significant cutoff point occurs at 80 dB (roughly the sound
of a vaccum cleaner). Sounds of this intensity or louder are considered hazardous
to hearing. The longer the ear is exposed to noise, the more damage it causes
to hearing. The effect is cumulative and irreversible.
When it is hard to distinguish
between the inability to hear because of a noisy enviornment or because of an
actual physical impairment, it's time for a hearing test.
P.S. Even moderate levels
of noise can prove detrimental to hearing, given enough time.
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