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Research Outline
Prepared for Mathieu F. | Delivered July 3, 2020
Noise-Induced Damage to Ears
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Goals
To provide factors that cause noise-induced damage to ears to help prevent hearing damage to workers.
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Early Findings
Noise-Induced Hearing Loss
According to the National Institute on Deafness and Other Communication Disorders (NIDCD), noises that are at/above
85 decibels
can lead to hearing loss.
According to the CDC, loud noises are harmful to the inner ear (cochlea). "A one-time exposure to extreme
loud sound
or listening to loud sounds for a long time can cause hearing loss".
Hair cells in the cochlea enable the brain to detect sounds. "Up to
30% to 50%
of hair cells can be damaged or destroyed" before any change in hearing can be measured. Hearing loss is noticed after many of these hair cells have been destroyed.
Factors That Influence Hearing Loss
According to the American Speech-Language-Hearing Association (ASHA), the risk of noise-induced hearing loss is influenced by three factors:
Noise level
The duration that one hears the noise
The closeness/proximity to the noise
Noise Level is measured by sound-level meters. Noise levels are recorded in
decibels
or dBA.
Sounds at
70 dBA
or lower are safe to be listened to for any duration of time.
Sounds at
85 dBA
can cause ear damage when listened to for more than 8 hours.
According to ASHA, "if the sound goes up to
88 dBA,
it is safe to listen to those same sounds for 4 hours. And if the sound goes up to
91 dBA
", safe listening time is 2 hours.
Sounds at
120 dBA
or higher are not safe to be listened to for any period of time. These include fireworks (
150 decibels
), firearms (
140 decibels
), jackhammer (
130 dBA
), and a jet plane takeoff (
120 dBA
).
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