Measuring how dangerous sound levels are is based upon how loud the sound is and how long you are exposed to it. Decibels, which measure volume, are logarithmic, which means an increase of 3 decibels doubles the volume. At any decibel level there is a ‘safe amount’ of time you can be exposed to sound before it can cause permanent damage; with every increase of 3 decibels the safe amount of time you have halves. See our handy decibel chart with decibel levels of general sounds and corresponding safe times.