by Daniel Fink, MD, Chair, The Quiet Coalition
Consumer Reports continues to cover issues of noise and health, which is a good thing. The only problem with this Consumer Reports article is that falls into a common trap and cites the occupational recommended exposure level of 85 A-weighted decibels for application to the public. This is a misuse of the occupational exposure recommendation that is sadly all too common.
Noise is different from other occupational exposures, e.g., ionizing radiation or toxic solvents, because exposure continues outside the workplace, all day long, all year long, for an entire lifetime.
In 1974, the Environmental Protection Agency adjusted the National Institute for Occupational Safety and Health recommended exposure level for the additional exposure time–24 hours a day instead of 8 hours a day at work, 365 days a year instead of 240 days in the factory, to calculate that the safe noise exposure level to prevent hearing loss was a time-weighted average of only 70 decibels.
The EPA did not adjust for lifetime exposure, probably because in 1974 the life expectancy of a man was only 67 years. But with people living on average to near 80, the additional years of noise exposure may account for the very high prevalence of hearing loss in older people.
The NIOSH Science Blog post on February 8, 2016, covered this topic, and I wrote about it in the American Journal of Public Health in 2017. In a requested blog post, I explained additional reasons why the real safe noise exposure level to prevent hearing loss has to be lower than 70 decibels.
I recently had this insight: the World Health Organization recommends only one hour of 85 A-weighted decibel noise exposure daily because after only one hour it is impossible for the listener to achieve the only evidence-based safe noise level to prevent hearing loss, which is the EPA’s 70 dB daily noise dose. An occupational noise calculator shows this calculation. So, 85 decibels isn’t safe for workers’ hearing, and it certainly isn’t safe for the public.
Our ears are like our knees–we only have two of them–but unlike knees, our ears can’t be replaced. So protect what you have and remember: it is sounds too loud, it IS too loud!