Finally, some sound advice about noise

by Daniel Fink, MD, Chair, The Quiet Coalition

Photo credit: Centre for Ageing Better

Hearing Health Foundation recently published a webpage titled: “What Are Safe Decibels?” It is gratifying to see accurate information about safe noise exposure levels presented, rather than mindless citation of the industrial-strength 85 dBA* recommended noise exposure limit from the National Institute for Occupational Safety and Health, often described as being safe for the public even without A-weighting.

Occupational exposure limits are eight hours per day, 50 weeks per year for 40 years. Members of the public are not exposed to continuous 85 dBA noise for eight hours every day, but are exposed to noise 24/7, from birth to death.

Why does mention of the only evidence-based safe noise exposure level of 70 decibels (dB) matter, rather than 85 dB or dBA? It appears to be part of human nature to want more. This is probably the result of a complex set of genes coding for behaviors that allowed humans and our primate and invertebrate ancestors to survive. We want more money, more food or another drink. If the speed limit is 65 mph, we go 70 or 75 mph.

Most people don’t know that the decibel scale is logarithmic, so if they are told that 85 dB is safe, they think, “What’s the matter with a little more noise? 85 dB is only 20% more.” Unfortunately, that’s not true. Eighty-five decibel noise has more than 30 times harmful sound energy as 70 dB sound.

Impulse noise has a disproportionate effect on hearing for workers, and since everyone’s ears are anatomically and physiologically the same, that is undoubtedly true for members of the public, too. The actual safe noise exposure level to prevent auditory damage may be much lower, 55 dBA for a single noise event and a daily average of only 55-60 dB.

Thanks to our friends at Hearing Health Foundation for posting accurate information about safe noise exposure levels for the public. Please help HHF and The Quiet Coalition spread the word about safe noise exposure levels, and join us in our efforts to make the world a quieter and healthier place for all.

*A-weighting adjusts unweighted sound measurements to approximate the frequencies heard in human speech.