Sound is measured in decibels (dB). Each decibel is one tenth of a bel, which is a unit that measures the intensity of sound. For every six decibels, the intensity of the sound doubles. At 90 dB of uninterrupted sound, the limit of safe noise exposure is eight hours. For each six dB increase of uninterrupted sound thereafter, the limit of safe exposure is reduced by half.
It is important to know the approximate intensity of sound around you to protect your hearing.