Hearing-loss risk threshold should drop from 85 to 75 dB for full protection

Evidence

Still, typical noise-induced hearing loss develops over the course of time. The loss can remain unnoticed until speech intelligibility begins to suffer. For long-term noise exposures, implying years or decades of exposure, the daily risk threshold has often been quoted to be 85 dB SPL (A-weighted, 8 hours a day), with the criterion of impaired hearing being a hearing threshold shift of 25 dB in middle–high frequencies. This kind of threshold shift already may decrease speech intelligibility. If healthy hearing is to be assured even after years of exposure to noise, the A-weighted risk threshold should be decreased to 80 dB, or even 75 dB. This is because the risk of hearing loss is somewhat individual, and, for example, music listening may suffer even with smaller hearing impairments. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 2687

Categorization

• XREF: Connects to noise research in One Square Inch of Silence and the conflict between regulatory floors and actual protection.
• SHARE: For audiologists and workplace-safety specialists: the 85 dB workplace standard may be too lenient by 10 dB.