NOISE POLLUTION

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noise pollution

Noise pollution is also known as sound pollution or environmental noise, Any unwanted sound which produces undesirable physiological effects on individual they effects in humans or other living organisms.

Level of Noise

Minimum sound pressure can be heard by human being=20µPa, and Noise level of 80 decibels or more for more than 8 hours a day increases tension and changes in breathing patterns. it was very harmful for humans and other living organism. Maximum sound produced by Rocket=200 Pa

Level denoted:-

noise pollution
Q is measured quantity and Qo is Std. reference quantity generally taken as 20µPa (if qty is taken as pressure)
  • If reference is sound Intensity (W/m2)

Averaging the sound pressure level

  • ̅̅̅ = Average Sound Pressure level in dB
  • N = Number of measurement reading
  • Ln = nth sound pressure level in dB.

Concepts of Noise

Sound Levels may vary with time and often do, Two kinds of Noise concepts are used to find the combined effect of different sound pressure levels Ln Concept, Leq Concept.

Ln Concept:

Ln represents the sound pressure level, Ln values are statistical noise levels used to assess noise levels from fluctuating noise sources over time. that will exceed for N% of the gauging time. 85dB value of L50 stands that sound level will exceed the value of 85dB 50% of the gauging time. The most commonly used Ln values are the L10 and the L50 or L90.

Ln calculation

Leq Concept

Sound Levels may vary with time and often do, Leq is the equivalent continuous sound level in decibels, equivalent to the total sound energy measured over a stated period of time and is also known as the time-average sound level, Ln represents the sound pressure level that will exceed for N% of the gauging time. 85dB value of L50 stands that sound level will exceed the value of 85dB 50% of the gauging time.

Leq

  • Li = Noise Level
  • ti = Time Duration

Noise Reduction

By raising the height of barrier near to the noise source, it can be reduced. Calculation of noise reduction is done using. Noise is frequently described as ‘unwanted sound’. Within this context, environmental noise is generally present in some form in all areas of human, animal, or environmental activity. The effects in humans of exposure to environmental noise may vary from emotional to physiological and psychological.

Noise Reduction  = noise reduction

NOISE POLLUTION

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