Car claxons. Dogs barking. Children screaming. Loud thumping music. Motorbikes roaring. Fire trucks and police cars. Drilling and hammering from constructions... If you live in a city, you’re familiar to these and many other sounds on a daily basis.
Sounds that, depending on their intensity, can be catalogued as noises, and which may have negative effects on our physical and mental health.
Vision and hearing are the two most abused senses in modern life. But unlike eyes - which have eyelids-, our ears have no natural protection to block over-stimulation, so it is up to us to protect them.
Although the World Health Organization established 55 decibels as the threshold to determine noise, the actual perception of what ‘noise’ is varies greatly from one individual to another, depending on factors such as personal sensitivity, cultural idiosyncrasy, and the mood of each person.
However, in general, those who make the noises are less sensitive to them than those who hear them.
There is enough scientific evidence that sustained exposure to noise is detrimental to our health.
In 2020, during the lockdowns due to the COVID-19 pandemic, many cities around the world suspended all ground and air traffic, shut down bars and cafes, and restricted all human activities.
As a result, the levels of noise pollution in cities dropped 70% in average, and residents of normally bustling cities heard for the first time sounds such as birds tweeting or the rustle of leaves.
The experience opened the eyes of many to the extreme level of noise pollution in cities, and its harmful effect in our lives.
Noise is invisible, and as such we adapt to it, get used to it, or even ignore it. But the invisibility of noise doesn’t mean it’s harmless.
Beyond mere annoyance, the constant exposure to noise can have harmful effects on our health.
The truth is noise can kill. And we’re not talking about sonic weapons.
You may have probably noticed the signs of “Please be quiet” and “Unnecessary Noise Prohibited’ in and around Hospitals and Clinics. And this is no mere whimsy.
Medical studies show that the noises that typically fill our cities can accelerate death in otherwise healthy people, and worsen pre-existing conditions.
According to the World Health Organization, noise pollution affects over 100 million people across Europe alone, and it’s one of the main causes for premature death.
Some of the health problems associated to sustained noise pollution include:
-Delayed cognitive development in children.
-Difficulty to concentrate.
-Insomnia.
-Anxiety and depression.
-Annoyance, stress, and mood shifts.
-Gastric problems (irritable bowel syndrome, gastritis, ulcers)
-Alterations in the immune system.
-Elevation of cortisol production (the ‘stress’ hormone).
-Elevated adrenaline levels (the ‘panic’ hormone).
-Increased heart rate.
-Hypertension.
-Vasoconstriction.
-Elevated blood pressure.
-Myocardial infarction.
In addition, harmful noises usually go accompanied by vibration or blows generated by sound waves, causing additional distress and physical discomfort.
Exposure to sustained noise can stimulate violent behavior, trigger headaches, disturb our emotional balance, cause nervous strain and extreme fatigue.
But noise doesn’t only affect adults.
Studies demonstrate that noise pollution also affect children’s heart rate, adrenaline and cortisol levels, as well as installing in them a sense of restlessness and anxiety.
Also, children in schools close to highways and loud traffic exhibit lower cognitive development than children who study in quiet classrooms.
Workers exposed to noisy environments suffer from stress, mental strain, lack of concentration, and distraction, which can in turn lead to accidents and low productivity.
Even nature suffers due to noise.
Just as it happens in humans, sounds of high intensity induce fear in animals, presenting the same physical effects we do: increased heart rate, a spike in the levels of adrenaline, anxiety, etc.
Noise pollution can impair the communication of the species, perturb their reproduction, affect their breeding and feeding patterns, and force them to abandon their habitat. Studies point at noise as one of the factors why some species may have become extinct, or drastically reduced its numbers.
Likewise, noise pollution also impacts pets and farm animals, affecting egg and milk production and stunting animal growth.
Even plants in a noisy environment present reduced growth and nutrient intake, and are more prone to disease and premature death.
But, what is noise?
Sound is measured in decibels (dB). The scale is algorithmic, so it’s proportion is not lineal. For instance, the difference between a ‘sound A’ of 50 dB, ‘sound B’ of 60 dB, is not ‘merely’ 10 dB - it means that ‘sound B’ is 10 times more intense than ‘sound A’, and 100 times more intense than another sound of 40 dB.
Although decibel readings are relative and do not render exact quantities, they do provide a powerful measure of the intensity of a sound.
The hearing range of a person is normally between 60 to 120 dB, and the World Health Organization categorizes as ‘harmful noise’ any sound beyond 70 dB.
Noise levels above 80 dB produce damaging effects to the ear, and exposure to noises above 100 dB can cause irreparable damage and permanent hearing loss.
However, intensity (volume) is not the only factor to consider.
The frequency of a sound - sometimes described as ‘sharp’ for high frequencies, and ‘bass’ for low frequencies -, also contribute to make sound either tolerable or disagreeable.
For instance, a beep may be low in volume but if its frequency is high, it may still cause discomfort (think of a mosquito buzzing in your ear.)
In general, high frequency sounds are more harmful to the ear than low frequency sounds.
In large cities, traffic noise generates up to 75% of the noise. Governments have taken measures to limit and control some of the major city noise pollutants, such as ground and air traffic, construction work, etc.
However, we are still exposed to an unending string of noises, even in our homes, specially for those who live in apartments. And while there are regulations to ensure appropriate levels of insulation among residential units, these are not always respected.
In addition, the narrow city streets covered with hard pavement and lined by tall concrete buildings act like resonance boxes, amplifying every sound.
But even in open nature sound expands indiscriminately. Depending on their location, a dog’s barks or the roar of a motorcycle can be heard miles away.
The fact is - sound travels, is often magnified through its advance, and invades areas distant from its originating point.
For instance, even at a distance of 800 mts, the register of a conventional leaf blower (80 - 112 dB) is still well above the 55 dB limit suggested by the World Health Organization as safe.
Noise can even travel faster under water. Instruments off the coast of North America can detect seismic air guns -used to locate oil and gas deposits in the ocean deep - as far away as the Brazilian coast.
Thus, it’s important to control noise at its origin.
Due to our constant exposition to city noises, we’ve become less aware of how loud and disturbing they can be - specially in regards to the noise we make.
Not long ago, I read the news of a man who’d received multiple complaints from his neighbors due to his dog’s barking. Decided to quell the dispute, he measured the decibels of his dog’s barks to prove them wrong - and was astonished at its loudness.
Dog barking ranges from 70 to 113 decibels - that is, louder than a motorcycle and in the range of what qualifies as “harmful noise”.
Other common culprits of noise pollution in cities include vacuum cleaners, cars and trucks, motorcycles, street sweepers, lawn mowers, leaf blowers, stadiums, and school yards, to name only a few.
However, according to a poll carried out by the Greater Boston Noise Report, 79% of responders believed that the noise they made with their leaf blowers was either not noticed, or that it didn’t matter.
It is noticed and it does matter, was the reply of the neighbors.
In addition to the harmful effects of noise over our health, one of the most worrying consequences is early hearing loss.
According to the center for Disease Control and Prevention, hearing loss is the third most common chronic health condition in the United States, over diabetes and cancer.
Tinnitus - the persisting ringing in your ear- is the first indication that something’s not quite right with your hearing.
Tinnitus is caused by the death of the nerve filaments that capture and transport the sound waves to our brain. A number of them die naturally every year due to the aging process, and like all nerves, they are not replaced.
However, repeated exposure to harmful noise levels can accelerate this process, leading us to premature hearing loss.
Other indications that we may present some level of damage in our hearing are the feeling of “void” after a loud concert, hearing ‘permanent rain’, vertigo, and constant dizziness, among others.
Some lessen the importance of hearing, deeming it a secondary sense, not as important as vision. But without adequate hearing we become prey to accidents and costly misunderstandings.
For instance, not hearing when a vehicle comes behind us, or misunderstanding important instructions or information. Bad hearing hinders our efficient communication, and can also impact our balance and stability, making us prone to accidents.
For all these, and because we all make some amount of noise during our normal daily activities, controlling noise pollution should be a personal and a communal responsibility.
Some recommendations to control noise pollution are:
* Be mindful of the noise you make, specially if you live in close quarters with others.
* Keep a moderate volume when using earbuds and earphones (the latter being slightly safer to your hearing.)
* Avoid making excessive or unnecessary noise - this way you will not become used to it, you’ll protect your hearing, and you’ll avoid disturbing others.
* When using machines (leaf blowers, lawn mowers, vacuum cleaners, etc.) favor those that make the least noise, or better still: use zero-emission options (rakes, brooms, etc.)
* Install insulation panels and secondary glazing on windows exposed to high levels of noise.
* Move pets and plants away from noisy environments.
* When in an environment of harmful noise levels ( at a Rock concert, while using a lawn mower, etc.), use earplugs or earmuffs to protect your ears.
* Do not leave your pets unattended and, in the case of dogs, teach them not to bark unnecessarily.
* Keep your machines properly adjusted and maintained; faulty machines will create higher levels of noise.
* Give yourself ‘silence breaks’ - this will refresh your ears, give your nerves a pause, and will help you notice harmful levels of noise.
Did You Know that...?
April 12th is the International Day of Noise Pollution Awareness.
To Learn More
Visit the page of Noisy World for more information about the effects of noise in our health and what’s being done about it.
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