Prolonged exposure to high pitched noise may damage the eardrum and result in permanent loss of hearing. The most alarming effect of noise pollution on the humans is impairment of hearing. The outdoor sources of noise pollution include the traffic on the roads, aircrafts, industriesand social events in which loudspeakers are used at full volume. The indoor sources of noise pollution include household gadgets like television, music systems and mixer grinders. There are various indoor and outdoor sources of noise. Supersonic airplanes create a shockwave called sonic boom which, on hitting the ground, damages the window panes and building structures. The high intensity of noise also affects non-living things like buildings. When animals are subjected to intense sound levels, the noise does damage to their hearing mechanism and stress response. Noise has adverse effects on animals too. Though these estimates vary from person to person, but generally people start feeling pain and discomfort at the noise level of 100 decibels. Human ear is known to be sensitive to an extremely widerange of intensity from 0 to 180 decibels. Sound is measured by many complex systems, but the best known unit of measurement is decibel, a unit named after Sir Alfred Bell. Noise is known to have unpleasant effects on humans and cause discomfort to the ears. However, any sound that is not desired by the recipient is called noise. Without sound, no verbal communication between human beings is possible.