What Is A Safe Noise Level For The Public?
What is a safe noise level for the public? In an editorial in the January 2017 issue of the American Journal of Public Health, available online now, I answer this question.
There are three safe noise levels, depending on which adverse impact of noise is to be avoided. (The terms “noise” and “sound” are used interchangeably. Some experts state that we hear noise but measure sound.) These levels were calculated by the Environmental Protection Agency in 1974, and have withstood the test of time:
- To prevent interference with human activities, sound levels must be below 45 decibels. That is almost “library quiet.”
- To prevent non-auditory health impacts of noise, the daily average noise exposure must be less than 55 decibels. Noise increases stress hormone levels, increases the risk of high blood pressure and heart disease, and has been correlated with obesity and other health problems. These health impacts are reviewed by Hammer et al. and Basner et al.
- To prevent hearing loss, the daily average noise exposure must be less than 70 decibels. Being deaf in old age is likely not part of the normal aging process, but rather the cumulative effect of a lifetime of too much noise.
Two important topics not discussed in the editorial due to space limitations are the disability rights aspects of indoor noise and the fact that there is no such thing as temporary auditory damage:
- Even those with normal hearing have difficulty understanding speech in a noisy environment. For those with hearing loss, loud noise in restaurants and stores makes it impossible to follow a conversation, even with hearing aids. Noise worsens tinnitus and hyperacusis. A noise level under 60 decibels is required to allow those with hearing loss to understand speech.
- Recent research demonstrates that there is no such thing as temporary auditory damage. Noise causes “Hidden Hearing Loss,” not detected by standard audiometric techniques. If there is temporary muffling of sound or ringing in the ears after noise exposure, permanent damage has occurred. This synaptopathy, damage is to nerve junctions in the auditory system, may explain why older people have trouble following one conversation among many in a noisy environment.
As noted in the editorial, in the absence of an explicit federal noise standard for the public, an occupational noise exposure standard of 85 decibels appears to have become the de facto safe federal noise level. This is far too loud. A workplace standard is not a safe noise leve for the public. The decibel scale is a logarithmic one, so an 85 decibel sound has 31.6 times more energy than a 70 decibel one, not 21% more, even though it is perceived as only twice as loud.
What does this mean for health professionals and the American public? It means that based on strong scientific evidence we should now push for quiet to protect our health and that of our children and communities, just as we fought to end exposure to secondhand smoke. Noise is like secondhand tobacco smoke in that it is both a nuisance and a health hazard. Secondhand smoke causes cancer and lung problems. Noise causes hearing loss, tinnitus, and hyperacusis, is strongly correlated with non-auditory health impacts, and makes it impossible for those with auditory disorders to participate fully in society.
Opponents of noise regulation mock those who want quiet as “NIMBYs,” radical environmentalists, or sensitive souls bothered by noise that doesn’t bother others, but we are concerned about our health and quality of life. We don’t want to be deaf in old age. We don’t want to have heart disease or be obese. We don’t want to suffer excess morbidity and mortality from noise exposure. We don’t want our activities interrupted. Federal policy, as stated in the Noise Control Act of 1972 is “to promote an environment for all Americans free from noise that jeopardizes their health and welfare.” We want our right to quiet protected, especially those of us with auditory disorders. It’s just like secondhand smoke.
People used to smoke everywhere- restaurants, stores, hospitals, airplanes, at work- but we now live in an essentially smoke-free society. People can still smoke, but not where others have to smell or inhale their secondhand smoke. The same is true for noise. People should still be allowed to make all the noise they want, just not where others have to hear it.
We need to start working to educate elected officials and public health authorities that noise is a danger to health. The American Journal of Public Health editorial is “open access”, so it is available to all. More information will be posted about noise and health on The Quiet Coalition site over the next several months. Please use this information to let your local, state and federal representatives know that noise- whether from background music in restaurants and stores turned up to rock concert levels, from leaf blowers and lawn mowers, from motorcycles with illegally modified exhausts, from helicopters and airplanes, from unnecessary horn-based alerts on vehicles, in movie theaters and concert halls and sports arenas- is a health and disability rights issue. Let them know what the safe noise levels are. The goal of noise regulations, adapted from radiation exposure regulations, should be ALARA, As Low As Reasonably Achievable.
We have a right to quiet. And we have much work to do to make the world quieter, one decibel at a time.