noise pollution


Noise pollutants is likewise referred to as sound pollutants or environmental noise, Any undesirable sound which produces unwanted physiological outcomes on a person they outcomes in human beings or different dwelling organisms.

Level of Noise

A minimum sound strain may be heard by a human being=20µPa, and a Noise degree of eighty decibels or greater for greater than eight hours an afternoon will increase anxiety and adjustments in respiratory patterns. it changed into very dangerous for human beings and different dwelling organisms. The maximum sound produced by Rocket=2 hundred Pa

Level denoted:-

 L=10log_{10}\left(\begin{array}{c}Q\ Q_{0}\end{array}\right) decibel(dB)

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 the sound level will exceed the value of 85dB 50% of the gauging time. The maximum typically used Ln values are the L10 and the L50 or L90.

Ln calculation

Leq Concept

Sound Levels can also add range with time and regularly do, Leq is the equal non-stop sound degree in decibels, equal to the total sound energy measured over a said time frame and is likewise referred to as the time-common sound degree, Ln represents the sound strain degree so as to exceed for N% of the gauging time. 85dB fee of L50 stands that sound degree will exceed the fee of 85dB 50% of the gauging time.


  • Li = Noise Level
  • ti = Time Duration

Noise Reduction

By elevating the peak of the barrier close to the noise source, it is able to 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


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