Noise Pollution Formula Sheet

Characteristics of Sound and Noise Formula Sheet

1. Frequency

f = 1 / T

Where:
T = Time Period

2. Wavelength

λ = C / f

Where:
C = Velocity of Sound Wave

3. RMS Pressure

P_rms = √[(1/T) ∫₀^T P²(t) dt]

Where:
P(t) = Pressure at any time t

4. Sound Intensity

I = W / a = P² / (ρC)

Where:
W = Power of sound in watt
a = Unit area perpendicular to the direction of wave motion
ρ = Density of air or medium (kg/m³)

5. Sound Level

L = log₁₀ (Q / Q₀)

6. Sound Pressure Level

L_p = 20 log₁₀ (P_rms / 20 μPa) dB

7. Sound Intensity Level

L_I = 10 log₁₀ (I / 10^-12) dB

8. Averaging Sound Pressure Levels

L̄_p = 20 log₁₀ [ (1/N) Σ 10^Lp/20 ]

9. Equivalent Noise Level

L_eq = 10 log Σ (10^Li/10 × t_i)

10. Noise Reduction

Noise Reduction (dB) = 10 log₁₀ (20H² / λR)

Where:
R = Distance between barrier and receiving point

Note: All formulas are commonly used in Environmental Engineering and Noise Pollution analysis.

Author

Mohan Dangi
Civil Engineer | Environmental Engineering Content Creator

Disclaimer

This formula sheet is prepared for educational and informational purposes only. Although every effort has been made to ensure accuracy, the author is not responsible for any errors, omissions, or consequences arising from the use of these formulas and calculations.

Users are advised to verify calculations with relevant standards, textbooks, IS codes, or professional engineering practices before applying them in academic, research, or field projects.