Noise is a significant source of hearing loss, but you can protect your hearing. An important first step is to understand how noise causes hearing loss.
Loud Noise Can Cause Hearing Loss Quickly or Over Time
Hearing loss can result from a single loud sound (like firecrackers) near your ear. Or, more often, hearing loss can result over time from damage caused by repeated exposures to loud sounds. The louder the sound, the shorter the amount of time it takes for hearing loss to occur. The longer the exposure, the greater the risk for hearing loss (especially when hearing protection is not used or there is not enough time for the ears to rest between exposures).
Here are some sources of loud noise that you may be exposed to. If you are repeatedly exposed to them over time, they can cause hearing loss.
Common Sources of Noise and Decibel Levels
Sound is measured in decibels (dB). A whisper is about 30 dB, normal conversation is about 60 dB, and a motorcycle engine running is about 95 dB. Noise above 70 dB over a prolonged period of time may start to damage your hearing. Loud noise above 120 dB can cause immediate harm to your ears.
The table below shows dB levels and how noise from everyday sources can affect your hearing.
Sounds May Be Louder Than What You Hear
How loud something sounds to you is not the same as the actual intensity of that sound. Sound intensity is the amount of sound energy in a confined space. It is measured in decibels (dB). The decibel scale is logarithmic, which means that loudness is not directly proportional to sound intensity. Instead, the intensity of a sound grows very fast. This means that a sound at 20 dB is 10 times more intense than a sound at 10 dB. Also, the intensity of a sound at 100 dB is one billion times more powerful compared to a sound at 10 dB.
Two sounds that have equal intensity are not necessarily equally loud. Loudness refers to how you perceive audible sounds. A sound that seems loud in a quiet room might not be noticeable when you are on a street corner with heavy traffic, even though the sound intensity is the same. In general, to measure loudness, a sound must be increased by 10 dB to be perceived as twice as loud. For example, ten violins would sound only twice as loud as one violin.
The risk of damaging your hearing from noise increases with the sound intensity, not the loudness of the sound. If you need to raise your voice to be heard at an arm’s length, the noise level in the environment is likely above 85 dB in sound intensity and could damage your hearing over time.
Source: CDC.GOV
