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At what noise exposure levels can permanent hearing loss occur?
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noise pollution
Learn about the impact of underwater noise on marine animals, notably harbour porpoises.
Permanent hearing loss, known as noise-induced hearing loss, occurs when excessive sound levels and durations of exposure cause irreversible damage to the sensitive hair cells of the inner ear.12
Regarding specific exposure levels:
- General Thresholds: Hearing loss typically does not occur at sound pressure levels (SPLs) below 80 dBA. It is recommended that eight-hour exposure levels be kept below 85 dBA.1
- Repeated Exposure: Most individuals who are repeatedly exposed to noise levels exceeding 105 dBA will experience some degree of permanent hearing loss. Repeated exposure to sounds in excess of 80 to 90 decibels can cause a gradual deterioration of hearing.13
- Single Exposure: A single exposure to an extremely intense sound, such as an explosion, can result in severe and permanent hearing loss.3
Because hearing loss often begins at higher frequencies (4,000 to 6,000 hertz), the damage may go unnoticed until it progresses to lower frequencies essential for speech. Protecting one's hearing is a vital health practice, as these physiological changes are often irreversible.32