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The day–evening–night noise level or L den is a 2002 European standard to express noise level over an entire day. It imposes a penalty on sound levels during evening and night [ 1 ] and it is primarily used for noise assessments of airports , busy main roads, main railway lines and in cities over 100,000 residents.
The day-night average sound level (Ldn or DNL) is the average noise level over a 24-hour period. The noise level measurements between the hours of 22:00 and 07:00 are artificially increased by 10 dB before averaging. This noise is weighted to take into account the decrease in community background noise of 10 dB during this period.
When sound levels reach a high enough intensity, the sound, whether it is wanted or unwanted, may be damaging to hearing. [3] Environmental noise monitoring is the measurement of noise in an outdoor environment caused by transport (e.g. motor vehicles, aircraft, and trains), industry (e.g. machines) and recreational activities (e.g. music).
Washington [vague] (Chapter 70.107) sets maximum levels in dB(A) but allows 5 dB(A) more if the sound is only 15 minutes in an hour, or 10 dB(A) for 5 minutes in an hour. Numerous cities have fixed levels, permitting excess levels for short times (e.g., Dallas, TX, Chapter 30) while others use Leq (Lincoln, NE, Chapter 8.24).
Ambient noise level is measured with a sound level meter. [4] It is usually measured in dB relative to a reference pressure of 0.00002 Pa, i.e., 20 μPa (micropascals) in SI units. [5] This is because 20 μPa is the faintest sound the human ear can detect. [5] A pascal is a newton per square meter. The centimeter-gram-second system of units ...
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).
Within the European Union 40% of people are exposed to environmental noise in their daily commutes on the road which exceeds 55 dB(A). During the daytime, approximately 20% of people are exposed to environmental noise levels above 65 dB(A) and during the nighttime, 30% of people are exposed to environmental noise above 55 dB(A). [23]
Main menu. Main menu. move to sidebar hide. Navigation Main page; Contents; ... The noise level is the level of noise. Specifically, it may refer to: Noise (electronics)
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