Noise and Hearing
Noise and Hearing
When an individual is over-exposed to excessive sound levels, sensitive structures of the inner ear can be damaged. This can result in permanent noise-induced hearing loss (NIHL). These structures can be injured by exposure to a brief but intense sound, such as an explosion, or from regular exposure to excessive sound levels over time. NIHL can be prevented through the control of sound levels or proper use of hearing protection devices (HPDs), such as earplugs or earmuffs.Sounds louder than 80 decibels are considered potentially dangerous. Both the amount of noise and the length of time of exposure determine the amount of damage. Hair cells of the inner ear and the hearing nerve can be damaged by an intense brief impulse, like an explosion, or by continuous and/or repeated exposure to noise. Examples of noise levels considered dangerous by experts are a lawnmower, a rock concert, firearms, firecrackers, headset listening systems, motorcycles, tractors, household appliances (garbage disposals, blenders, food processors/choppers, etc.) and noisy toys. All can deliver sound over 90 decibels and some up to 140 decibels.
Examples of sound levels:
30 dB - whisper
60 dB - conversational speech
80 dB - busy street, alarm clock
90 dB - lawnmower
100 dB - chain saw, snowmobile, pneumatic drill
110 dB - rock music
EVIDENCE OF OVER-EXPOSURE:
- Tinnitus or head noise
- High frequency hearing loss
- Hypersensitivity and Loss of sensitivity