What Level Of Decibel Is Harmful?
Published: July 12, 2023
Updated: July 13, 2023
At one point or another, you might have wondered “what decibel level is harmful to my ears”. We hear so many sounds on a daily basis, and all at various volume levels, so it’s only natural to wonder at what point we may be damaging our hearing.
As with a number of other “harmful” things, it’s not as clear-cut as we would like it to be. There are a number of influencing factors that we need to factor in, such as how long we are exposed to the noise, whether we are using safety equipment and the fact that everyone’s hearing, and sensitivity to sounds, is unique.
What decibel is harmful?
Theoretically speaking, any noise level that is above 85dB is considered harmful to one’s hearing. Sounds at, or above, this level can have lasting, permanent effects on your hearing, and will most likely lead to a reduction in your hearing ability. This won’t be immediate, but you will not need to be exposed to these sounds for very long periods for the effects to take hold.
As this isn’t an exact science, there is no determining how long you can be bombarded with sound at 85dB or higher, so it’s considered best practice to remove yourself as quickly as possible from the noisy area, or put on safety equipment as quickly as possible.
Furthermore, any sound at 120dB will have an immediate impact on your hearing, and in some cases, can be severe enough to rupture your eardrum as soon as it hits your ears. Sounds at these intense levels can also damage the tiny hairs, stereocilia, in your ears. These hairs in your cochlea react to the vibrations from incoming sound waves, and are responsible for sending electrical signals to your brain to process the sound.
Unfortunately, hair cells cannot regenerate, regrow, or heal, and so if they are damaged, they can never return to full function, diminishing your hearing ability. Also, if these hair cells are sufficiently damaged, they can die, which would lead to permanent hearing loss. You needn’t worry too much – examples of 120dB sound include live indoor music concerts and jet engines. Still, it’s important to understand that there are a wide variety of factors that you should consider as well.
What is above 85dB?
There are a number of everyday sounds that meet, or edge over, the 85dB level which can impact your hearing. Examples include heavy traffic, a motorcycle, and even a noisy restaurant. Before you rush off to grab your nearest pair of noise-canceling headphones, there are some other factors to consider as to why this isn’t an inherently bad thing.
Two of the most important aspects to remember when it comes to this potentially dangerous dB level, include the amount of time spent in these environments, distance, and natural noise suppression.
The dose makes the poison
In the words of Swiss physician, Paracelsus: “the dosage makes the poison”. While this was solely about toxicology, the basic principle translates to our example here; the decibel level (depending) is not always the issue but the time spent exposed to it is. Sitting in a noisy restaurant for an hour or two, or a motorcycle whizzing past you is not going to really cause any harm to your hearing – otherwise, restaurants would be out of business. However, depending on a person’s individual sensitivity to certain frequencies and dB levels, prolonged exposure to 85dB sounds would result in damage to your hearing.
Distance from noise source
Distance also plays a significant role in the potentially harmful effects of noise. The further you are from the source of the noise, the less harmful it can be to your hearing health. Hearing an 85 dB sound right next to the ear is going to be far more harmful than hearing the same sound from 100 feet away. This is mostly due to the reduced intensity of the sound as it travels through the air, reverberating off far more obstacles, before reaching your ears.
Natural noise suppression
Another important detail to understand is that sound, or noise, doesn’t exist in a vacuum – literally and metaphorically, in this case. We scarcely experience sound without it being dampened by something. In most cases, the air that sounds travels through is enough to dampen the harmful effects of these examples, but there are a variety of other elements as well.
If we take a restaurant scene for example; the sound is not only dampened, or suppressed, by the air but also by all the furniture, walls, ceilings, and so on, that sound bounces off before it hits your ears. If a restaurant is outside, things like the trees, leaves, and even the wide open space are enough to quell the harmful effects of these loud noises – to a certain extent.
Safe Noise Levels
Sounds under 85 dB are generally considered safe. Let’s take a look at a few common decibel examples that fall below the threshold.
- 10 dB: normal breathing
- 20 dB: leaves rustling, mosquito buzzing
- 30 dB: whispering
- 40 dB: quiet office or residential area, light rain
- 50 dB: moderate rainfall, refrigerator
- 60 dB: normal conversation, electric toothbrush
- 70 dB: washing machine, dishwasher
- 80 dB: noisy restaurant, vacuum cleaner, garbage disposal
- 85 dB: Blender, heavy traffic
Harmful Noise Levels
Sounds exceeding 85 dB can be dangerous to your hearing health, depending on distance and intensity. Here are some examples:
- 90 dB: lawnmower, shouting conversation
- 95 dB: electric drill
- 100 dB: night club, train, snowmobile
- 110 dB: power saw, jackhammer, motorcycle
- 120 dB: ambulance siren, chainsaw, rock concert
- 130 dB: stock car race, jet engine
- 135 dB: loud squeaky toy (next to ear)
- 140 dB: airplane takeoff
- 145 dB: fireworks
- 150 dB: shotgun blast
As we said earlier, it’s not an exact science as to how long you can be exposed to certain dB levels without risk but there are guidelines that have been put together to minimize potential risk. Factors such as distance and intensity can also affect these figures, but these are generally what is permissible by the National Institute for Occupational Safety and Health (NIOSH). You can find the times below:
- 85 dB: 8 hours
- 88 dB: 4 hours
- 91 dB: 2 hours
- 94 dB: 1 hour
- 97 dB: 30 minutes
- 100 dB: 15 minutes
- 103 dB: 7.5 minutes
- 106 dB: 3.75 minutes
As you can see, each interval of 3 dB results in half the time needed for hearing loss to occur. Sounds above 110 dB can cause hearing damage almost immediately.