Noise Pollution Calculator Formula

Understand the math behind the noise pollution calculator. Each variable explained with a worked example.

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Formulas Used

Combined Noise Level

combined_level = combined_db

Level at Distance

at_dist = at_distance

vs WHO Limit (65 dB)

vs_who = at_distance - 65

Safe Exposure at This Level

max_safe_hours = 8 / pow(2, (at_distance - 85) / 3)

Variables

VariableDescriptionDefault
source1_dbPrimary Noise Source(dB)70
source2_dbSecondary Noise Source(dB)60
exposure_hoursDaily Exposure Hours(hours)8
distance_ftDistance from Source(feet)50
combined_dbDerived value= 10 * log(pow(10, source1_db / 10) + pow(10, source2_db / 10)) / log(10)calculated
at_distanceDerived value= combined_db - 20 * log(distance_ft / 3) / log(10)calculated

How It Works

How to Calculate Noise Pollution

Noise levels are measured in decibels (dB) on a logarithmic scale.

Combining Sources

Combined dB = 10 * log10(10^(dB1/10) + 10^(dB2/10))

Distance Attenuation

dB at distance = Source dB - 20 * log10(distance / reference)

Reference Levels

  • Whisper: 30 dB
  • Conversation: 60 dB
  • Traffic: 70-85 dB
  • Construction: 80-100 dB
  • WHO recommends daytime limit of 55-65 dB

    • Worked Example

    A 70 dB traffic noise and 60 dB HVAC system, 8 hours exposure at 50 feet.

    source1_db = 70source2_db = 60exposure_hours = 8distance_ft = 50
    1. 01Combined: 10 * log10(10^7 + 10^6) = 10 * log10(11,000,000) = 70.4 dB
    2. 02At 50 ft: 70.4 - 20 * log10(50/3) = 70.4 - 24.4 = 46.0 dB
    3. 03vs WHO: 46.0 - 65 = -19.0 dB (below limit)

    Ready to run the numbers?

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