What level and time can cause permanent hearing loss?

What level and time can cause permanent hearing loss?

• A. Over 100 dB for 30 minutes
• B. Over 85 dB for more than 8 hours/day (cumulative)
• C. 60 dB for 24 hours
• D. 70 dB for 1 hour

Answer: (B)

Prolonged exposure to loud noise damages the tiny hair cells in the cochlea, and once those cells are harmed, they do not regenerate. The risk of permanent hearing loss increases when sound levels are high and exposure time is long. A widely used guideline is that exposure above about 85 dB SPL for a full workday or longer can lead to permanent damage, especially because the damage accumulates across the day. In other words, the cumulative effect of loud sounds over many hours stresses the auditory system beyond its ability to recover, increasing the chance of lasting hearing loss. Short, very loud blasts can cause temporary changes, but permanent loss is most strongly linked to long daily exposures at moderate-to-high levels. The idea that daily exposure exceeding 8 hours at 85 dB or more poses a real risk reflects the accumulation concept and explains why this option is the best answer.

Prolonged exposure to loud noise damages the tiny hair cells in the cochlea, and once those cells are harmed, they do not regenerate. The risk of permanent hearing loss increases when sound levels are high and exposure time is long. A widely used guideline is that exposure above about 85 dB SPL for a full workday or longer can lead to permanent damage, especially because the damage accumulates across the day. In other words, the cumulative effect of loud sounds over many hours stresses the auditory system beyond its ability to recover, increasing the chance of lasting hearing loss. Short, very loud blasts can cause temporary changes, but permanent loss is most strongly linked to long daily exposures at moderate-to-high levels. The idea that daily exposure exceeding 8 hours at 85 dB or more poses a real risk reflects the accumulation concept and explains why this option is the best answer.