"The whole strata community owes a huge debt of gratitude to you and the OCN executive. Much appreciated."
2.4.2 Sound pressure (Pa)
Sound pressure is the amount of air pressure fluctuation a noise source creates. We "hear" or perceive sound pressure as loudness.
Even very loud sounds produce pressure fluctuations which are extremely small (1 in 10,000) compared to ambient air pressure (i.e. atmospheric pressure).