The truth about noise

It’s no secret that noise is a bad thing. It can make us feel uncomfortable and annoyed, and it can even be detrimental to our health.

But how much do we really know about noise and the problems it poses? For example, do you know the difference between sound and noise?

Existing as a pressure wave that is created from vibrations in the environment or an object, a sound can be anything that is perceived by the human ear. As an integral part of our lives, sound comes in various forms — whether it is the singing of birds or the cascading of water — and is not necessarily just one specific vibration or frequency¹.

Noise, on the other hand, is simply unwanted sound². Reactions to noise can be a complicated affair, as there is no physical distinction between sound and noise. This makes noise highly contextual, and is affected by different characteristics such as volume, frequency, and pitch, as well as how much control we have over it. 

This could explain how a fan of heavy metal might enjoy the music while someone else might find it unbearable, or why the pleasant melody of wind blowing through the trees could become bothersome when it prevents you from clearly understanding the person you are having a conversation with.

In other words, a single sound could be either noise or not noise depending on what you want to hear. This is referred to as listener intent.

What is noise?

Imagine this: You are watching TV when someone comes up and starts talking to you. Which is the noise — the sound from the TV or the person’s voice? It all depends on what you want to hear. Listener intent helps you focus your attention on your desired sound while reducing background noise³.

However, loud noise can still be overwhelming, and becomes particularly problematic when it disturbs important activities such as sleep, learning, and work. 

The World Health Organization (WHO) recommends less than 30 A-weighted decibels (dB(A)) of noise in bedrooms and less than 40dB(A) outside of bedrooms for good quality sleep. A-weighted decibels is a system of measuring sound levels with the same sensitivity to different frequencies as the average human ear⁴. For reference, a person whispering in a quiet room is approximately 25dB(A)⁵.

Noise can affect your health

Exposure to noise levels above 40dB at night can result in sleep disturbance and awakenings. Good quality sleep is important for ensuring that our brain functions well during the day. It also plays a critical role in allowing our bodies to repair and recover themselves from a tough day’s work, in order to continue performing at peak condition. Therefore, sleep disturbance could lead to adverse effects to the human body.

For example, it could impact the hormonal changes that regulate our glucose levels as we sleep, which would lead to reduced glucose tolerance and increase the risk of type 2 diabetes⁶. What’s more, people experiencing interrupted sleep may find themselves at greater risk of depression, putting a strain on their mental health⁷. At noise levels above 55dB, elevated blood pressure and ischaemic heart disease may occur⁸, which can ultimately lead to heart attacks.

If you are interested in reading more about how noise can cause sleep disturbances and how it affects your body, check out this article!

In fact, a WHO study discovered that at least one million healthy life years are lost every year in Western Europe as result of exposure to environmental noise⁹. This positions noise as the second largest environmental cause of ill health, after air pollution¹⁰. On top of that, a UK study showed that exposure to noise above the recommended levels resulted in an additional 1169 cases of dementia, 788 cases of stroke, and 542 cases of heart attack in a single year¹¹.

Loud classrooms can hamper learning

Children in schools aren’t off the hook as noise can pose a negative impact in educational settings too. For example, studies have shown that children miss 25 percent of the words spoken by their teachers as a consequence of a noisy classroom¹².

In addition, a two month reading delay can be observed in British and Dutch primary school children due to an increase in transport noise of 5dB¹³. According to a German study, children may also experience hyperactivity, inattention, and emotional problems as a consequence of elevated noise levels¹¹.

The WHO recommends a noise level of less than 35dB(A) in classrooms in order to support optimal teaching and learning conditions. This is significantly lower than in many urban locations.

So, how can we deal with the problem that is noise? 

Although earplugs and noise-cancelling headphones can help reduce your exposure to noise, you wouldn’t necessarily want to have your ears blocked all the time. Conversely, good building design plays a crucial role in addressing the noise issue without impairing your physical comfort.

For example, the use of soundproof walls and acoustic tiles, along with measures such as quiet rooms, can significantly reduce unwanted noise and contribute to quieter, peaceful, and more restful environments.

Remarkably, stone wool products can be engineered to isolate and control vibrations and noise. This means that they make excellent insulation and acoustics tiles, thanks to their noise reduction and sound absorption qualities, which can quieten even the nosiest infrastructure sounds.

Ultimately, the world is teeming with noise. Knowing how to identify it, and learning how to overcome it, can help open the doors to a better quality of life.

Source(s):

^{1. Fisher, K.M., 2016, “Towards Understanding the Compression of Sound Information”}

^{2. Berglund, Birgitta, Lindvall, Thomas, Schwela, Dietrich H & World Health Organization. Occupational and Environmental Health Team, 1999, “Guidelines for community noise”. Geneva : World Health Organization.} 

^{3. Carlile, Simon, 2016, "The “meaning” in noise—Evidence for bottom-up information masking of within channel modulation coding of speech." The Journal of the Acoustical Society of America 139, no. 4: 2044-2044.}

^{4. Australian Academy of Sciences, n.d.}

^{5. United States. General Services Administration, 2007, “Denver Federal Center Site Plan Study: Environmental Impact Statement, Volume 1”}

^{6. Tasali et al, 2007.}

^{7. Niemann and Maschke, 2004.}

^{8. European Commission, 2016.}

^{9. World Health Organization, 2011, “Burden of Disease from Environmental Noise: Quantification of Healthy Life Years Lost in Europe”}

^{10. Coghlan, Andy, 2011, “Noise kills, and blights lives in Europe”}

^{11. European Union, 2015, “THEMATIC ISSUE: Noise impacts on health Environment Science for Environment Policy”}

^{12. Acoustic society, 2018.}

^{13. Rijksinstituut voor Volksgezondheid en Milieu, p.4}