Search results
Results from the WOW.Com Content Network
Environmental noise regulations usually specify a maximum outdoor noise level of 60 to 65 dB(A), while occupational safety organizations recommend that the maximum exposure to noise is 40 hours per week at 85 to 90 dB(A). For every additional 3 dB(A), the maximum exposure time is reduced by a factor 2, e.g. 20 hours per week at 88 dB(A).
Acoustic trauma is an injury to the inner ear that's often caused by exposure to a high-decibel noise. This injury can occur after exposure to a single, loud noise or from exposure to noises at significant decibels over a longer period of time. [medical citation needed] Many cases have included a period of reduced hearing after exposure to loud ...
The decibel (symbol: dB) is a relative unit of measurement equal to one tenth of a bel (B). It expresses the ratio of two values of a power or root-power quantity on a logarithmic scale. Two signals whose levels differ by one decibel have a power ratio of 10 1/10 (approximately 1.26) or root-power ratio of 10 1/20 (approximately 1.12). [1] [2]
Of these 65 million acquired the condition during childhood. [15] At birth ~3 per 1000 in developed countries and more than 6 per 1000 in developing countries have hearing problems. [15] Hearing loss increases with age. In those between 20 and 35 rates of hearing loss are 3% while in those 44 to 55 it is 11% and in those 65 to 85 it is 43%. [8]
Vinyl microgroove phonograph records typically yield 55-65 dB, though the first play of the higher-fidelity outer rings can achieve a dynamic range of 70 dB. [25] German magnetic tape in 1941 was reported to have had a dynamic range of 60 dB, [26] though modern-day restoration experts of such tapes note 45-50 dB as the observed dynamic range. [27]
The study found that no residential areas registered a decibel count of more than 65 decibels, the figure used by the Federal Aviation Administration (FAA) to determine if there is a noise issue ...
The ear can be exposed to short periods of sound in excess of 120 dB without permanent harm — albeit with discomfort and possibly pain — but long term exposure to sound levels over 85 dB(A) can cause permanent hearing loss. [31] There are two basic types of NIHL: NIHL caused by acoustic trauma; NIHL that gradually develops.
Noise pollution, or sound pollution, is the propagation of noise or sound with potential harmful effects on humans and animals.The source of outdoor noise worldwide is mainly caused by machines, transport and propagation systems.