From a biological (medical) point of view, noise is sound that is harmful due to its excessive intensity. The effect of noise is subjective (annoying, disturbing concentration and mental well-being) and objective (measurable hearing damage). The noise may have the character of non-periodic sound. Periodic noise (excessive sound of a tonal nature) typically causes damage where the cochlea processes the relevant frequencies. The decibel (dB) unit is most commonly used to measure noise intensity, similar to sound.
