Noise Level

A measure of Sound Pressure Level, given the symbol L. Various subscripts define the nature of the measurement, most commonly as follows:

L₁₀: Sound Level exceeded 10% of the time (peak level)

L₅₀: Sound Level exceeded 50% of the time (average or mean level)

L₉₀: Sound Level exceeded 90% of the time (ambient level); see Ambient Noise Level

L_A: Sound Level in decibels measured on the A scale; see Sound Level Meter

L_eq: Equivalent Energy Level

L_NP: Noise Pollution Level

L_dn or L_DN: day-night equivalent Noise Level; see Equivalent Energy Level

See: Loudness Level, Noise, Perceived Noise Level, Sound Level, Traffic Noise Index. Compare: Damage-Risk Criteria, Hearing Level.