The intensity of sound is measured in decibels (dB). 30 dB - 60 dB is for normal conversation, 90 dB- truck traffic, 100 dB - from construction site, 115 dB - sandblasting, loud rock concert, auto horn, 120 dB - 150 dB from jet engine. The undesired high level of sound is called as noise which causes pain and can injure unprotected ears.