For every increase of 5 dB in loudness, how does the permissible exposure time change?

The relationship between sound level and permissible exposure time follows a logarithmic scale due to the nature of human hearing and the impacts of noise exposure on hearing health. Specifically, every increase of 5 dB in sound intensity results in a halving of the permissible exposure time.

The rationale for this is grounded in the understanding that as sound pressure increases (measured in decibels), the risk of hearing damage also increases. Therefore, to maintain the same level of safety in terms of noise exposure, the amount of time one can be exposed to the sound must be reduced. If you were exposed to 85 dB for a specific duration, increasing to 90 dB requires cutting the permissible exposure time in half to mitigate the risk of hearing loss.

This principle is widely accepted in occupational safety guidelines regarding noise exposure, and it underscores the necessity of taking precautions as sound levels increase. Thus, the correct answer illustrates the essential guideline for protecting auditory health in environments where sound levels can escalate.