By Daniel Fink, MD, Chair, The Quiet Coalition
Jan 31, 2018.
It’s very frustrating to see headphones advertised as safe for children when they use the 85 decibel noise exposure standard without specifying a time limit. It shouldn’t be surprising, though, as even the National Institute on Deafness and Other Communication Disorders states, “[l]ong or repeated exposure to sound at or above 85 decibels can cause hearing loss.”
But 85 decibels is not a safe noise level without a time exposure limit. I wrote about this in the American Journal of Public Health in January 2017. This 85 A-weighted decibels (dBA) exposure standard is an occupational standard: The National Institute for Occupational Safety and Health recommends that workers get no more than 85 A-weighted decibels noise exposure, calculated for an average working life of 8 hours a day, 240 days a year, for 40 years. Even that exposure level doesn’t prevent all exposed workers from hearing loss. A-weighting reflects the frequencies heard by the human ear and A-weighting almost always lowers the sound measurement by 5-7 decibels. The decibel scale is a logarithmic scale, which means that 3 decibels more indicates a doubling of sound energy, and it is sound energy that destroys the cochlear hair cells, the basic sensory organ for hearing.
For children who may start using headphones as early as three years old, 40-years exposure to 85 decibels delivered directly to their ears via headphones means that they may be profoundly hearing impaired in their mid 40s. That’s not a good thing.
I suppose headphones with the occupational noise exposure level, A-weighted or not, as a volume limit are better than headphones without any volume limit. But parents and grandparents would be wise to avoid getting their little darlings these unsafe headphones, or any headphones, unless they want to buy them hearing aids when they get older.