## noise Pollution level (LNP) Calculator tool

noise Pollution level (LNP) is an evaluation of noise based on the combined influence of energy average and variable characteristics (expressed by standard deviation). The evaluation of noise is given by combining the influence of energy average and variable characteristics (expressed by standard deviation).

Many unsteady noise practices have shown that the degree of disturbance caused by fluctuation noise is greater than that caused by equal-energy steady noise, and the noise exposure change rate is related to the average intensity. It is proved by experiments that the actual pollution degree can be better reflected by adding a change amplitude of noise on the basis of equivalent progression sound level. This level of noise Pollution is a good way to evaluate air or road traffic noise. Therefore, noise Pollution level (LNP) formulas is:

LNP = Leq + Kσ

In theformula:

K -- constant number, 2.56 for traffic and aircraft noise;

σ - instantaneous sound level standard deviation during measurement.

where: Leq is equivalent sound level; σ is the standard deviation.

If noise follows Gaussian distribution, LNP=L50+d+d^2/60

where: d=L10 - L90; L10 is A sound level that occurs at or above 10% of the time or number of times in the measured time, and so on.

**noise Pollution level (LNP) **

noise Pollution level (LNP) Calculator = L _{ 50 } + L _{ 10 } -l _{ 90 } + (L _{ 10 } -

L _{ 90 }) ^{ 2 }

Here

NPL = noise Pollution level

L_{10} = More than 10% A sound level time

L_{50} = More than 50% A sound level time

L_{90} = more than 90% A sound level time