# Sound exposure

(Redirected from Sound exposure level)
Sound measurements
Characteristic
Symbol
Sound pressure  p · SPL
Particle velocity  v · SVL
Particle displacement  ξ
Sound intensity  I · SIL
Sound power  P · SWL
Sound energy  W
Sound energy density  w
Sound exposure  E · SEL
Sound energy flux  Q
Acoustic impedance  Z
Speed of sound  c
Audio frequency  AF

Sound exposure is the time average of squared sound pressure.

## Mathematical definition

Sound exposure during time T, denoted E and measured in Pa2·s, is given by:

$E = \frac{1}{T}\int_0^T p(t)^2\, \mathrm{d}t$

where:

• T is the time, measured in s;
• p is the sound pressure, measured in Pa.

## Sound exposure level

For other uses, see Sound level.

Sound exposure level (SEL) or acoustic exposure level is a logarithmic measure of sound exposure in comparison to a reference value.
Sound exposure level, denoted LE and measured in dB, is given by:

$L_E = 10 \log_{10}\left(\frac{E}{E_0}\right)~\text{dB}$

where:

• E is the sound exposure, measured in Pa2·s;
• E0 is the reference sound exposure, measured in Pa2·s.

The reference sound exposure is 400 μPa2·s for sound in air and 1 μPa2·s for sound in water.