Exposure to noise above which of the following db level causes permanent hearing loss?

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2018

Medical & Surgical Nursing

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2018

Explanation

90 dB.
Prolonged or repeated exposure to noise levels at or above 90 decibels (dB) can cause permanent, irreversible hearing damage, known as noise-induced hearing loss (NIHL).
Occupational Safety and Health Administration (OSHA) regulations mandate hearing conservation programs in workplaces where the average noise exposure over an 8-hour period is 85 dB or more.
Specifically, OSHA's permissible exposure limit is 90 dBA for an 8-hour workday. Exposure to levels above this without protection significantly increases the risk of permanent hearing loss over time.

Option A: A noise level of 60 dB is equivalent to a normal conversation and is not considered hazardous to hearing.
Option C: While exposure to 100 dB is definitely harmful and can cause damage much faster than exposure to 90 dB (within 2 hours), the initial threshold for risk over a standard workday is lower.
Option D: A noise level of 160 dB, such as a firearm blast, causes immediate, severe, and permanent damage known as acoustic trauma. The question implies a threshold for damage from prolonged or repeated exposure, not instantaneous trauma.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Noise-Induced Hearing Loss (NIHL) as background academic context rather than a clinical decision trigger.
Nurses play a crucial role in patient education regarding hearing protection. This includes advising on the dangers of loud music through headphones, occupational noise, and recreational noise (e.g., concerts, power tools).
In occupational health settings, nurses are involved in implementing and managing hearing conservation programs, which include noise monitoring, providing personal protective equipment (earplugs, earmuffs), and conducting audiometric testing.
What if the exposure was to 85 dB? At 85 dB, while the risk is lower than at 90 dB, it is still significant. This is the 'action level' set by OSHA, meaning employers must initiate a hearing conservation program, including monitoring and making hearing protection available, for an 8-hour time-weighted average exposure.

How to Approach the Question

First, identify the key terms in the question: 'noise', 'dB level', and 'permanent hearing loss'. This indicates the question is about the safety threshold for sound.
Recall or look for standard occupational health guidelines regarding noise exposure. The 8-hour workday is a common reference for chronic exposure risk.
Evaluate the options. 60 dB is too low (normal conversation). 160 dB is extremely high and associated with immediate trauma, not the threshold for prolonged exposure.
Differentiate between 90 dB and 100 dB. Both are harmful, but 90 dB is the widely recognized standard threshold for an 8-hour permissible exposure limit before significant risk of permanent damage begins.
Select the option that represents this initial threshold for long-term risk, which is >90 dB.

Concept Tested & Keywords

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