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Lden Calculation

The Lden indicator (for Level day-evening-night) represents the weighted average noise level during the day. The formula for the calculation of the Lden:

\[ Lden = 10 \log_{10} \left( \frac{1}{24} \left( 12 \times 10^{\frac{LAeq(6h-18h)}{10}} + 4 \times 10^{\frac{LAeq(18h-22h)+5}{10}} + 8 \times 10^{\frac{LAeq(22h-6h)+10}{10}} \right) \right) \]

  • LAeq in dBA, the equivalent sound pressure level on a period T
As showed above, the LAeq is majored to 5dB in the evening and 10dB in the night, to take into account the increased sensitivity of individuals to noise pollution during these two periods..