Urban noise pollution is making us deaf and killing us slowly, writes Aznim Ruhana Md Yusup
I LIVE in an apartment next to a major highway, and the sound of traffic is something that I deal with daily. It is bearable when the doors and windows are shut, but the motorcycle races on weekends are something else.
With the exception of rain, roadworks and presumably police roadblocks - though I've not witnessed any - the races happen regularly from midnight to 4am. Trespassing on the early morning calm, the racers ride unafraid and unabashed in a contest that has been going on for decades.
It is, of course, illegal, and yes, I am annoyed by it. I suppose my annoyance is further exacerbated given how powerless I am in this situation. But what's new to me is that this annoyance may also contribute to an early death.
In a study titled A Vision Of the Environmental And Occupational Noise Pollution In Malaysia published in the Noise And Health journal in 2014, Foo Keng Yuen from Universiti Sains Malaysia wrote: "(the) potential implications of noise exposure are numerous, pervasive, persistent, cumulative and augmented synergistically and antagonistically, with corresponding real (economic) and intangible (well-being) losses.
"An explicit link between environmental noise with the activation of sympathetic and endocrine systems has been witnessed, resulting in the changes of blood pressure, hypertension, peripheral vasoconstriction and cardiovascular disease."
DISCOMFORTING STRESS
The World Health Organisation has deduced the health effects of noise pollution into a pyramid (see infographic). And while feelings of discomfort affect a lot of people, it isn't too severe from a health perspective. But this can worsen over time.
"If you're constantly exposed to noise, what you would experience first of all is discomfort," says Dr Shailendra Sivalingam, an Ear, Nose and Throat specialist from Sunway Medical Centre.
"It progresses up to rising stress hormones and then your blood pressure goes up. As a result, with elevated cholesterol level, there's risk of heart disease. And because you're exposed to this constant noise even at night, you don't get to sleep very well, you don't get rested, and the body doesn't recover. The cycle repeats itself until it breaks to mortality."
It's a slow, indirect process, and easily overlooked. Urban noise pollution from traffic or construction is such that we have normalised it, gotten used to it and accepted it as part of life in a modern world.
Some of us may only realise noise in its absence, which speaks of how adaptable the human mind and body is, but that doesn't negate from the actual strain that we're putting ourselves through.
"You don't consider it as something bad because you've been exposed to it all your life," says Dr Shailendra. "But it's because you've been exposed to it your whole life, that it does affect you. But you don't realise the importance of it until it reaches that point where the effect is permanent and you can't recover."
GET AWAY NOW
A more direct effect of noise pollution is hearing loss, which can be temporary and permanent. Temporary hearing loss occurs when you're exposed to loud sounds for a limited amount of time, like during a concert or at a racing circuit, after which you find yourself unable to hear very well.
Permanent hearing loss is pretty much the same thing, except that you don't recover from it. It happens when you're constantly exposed to that loud sound, or it could also be a one-shot literal deafening experience, such as a firecracker that goes off next to your ear.
Dr Shailendra explains that the hearing organ in our ears is the cochlea. It's a liquid-filled chamber that contains hair cells that vibrate and move in a certain way, depending on the frequency of the sound wave that enters the organ. The vibration triggers an electrical discharge and enters the auditory nerve, sending a signal that is transmitted to the brain.
"These hair cells do not replace themselves," he says. "You have a finite number of cells. If they're damaged you lose the function of those cells. That means if there is a particular frequency at which the sound is very, very loud and the cells in that area are damaged, you will not get to hear that frequency again, because the cells don't replace themselves."
He adds: "The hair cells are living cells, they're metabolically active and have a source of energy within them that allows them to function. When you subject them to excessively loud noise, it means that you're working them too hard and they go into what is called metabolic exhaustion. They have exhausted all of their energy supplies."
Taking yourself away from the noise will give the cells time to replenish and get them to function normally again. But failure to do this can result in permanent hearing loss, warns Dr Shailendra.
The loudness of sound is measured in decibels. According to the aforementioned study, WHO's recommended noise level is 55 dBA (adjusted decibels) for daytime and 45 dBA for night time. Malaysia's planning guideline puts it at 65 dBA for day and 60 dBA at night.
Meanwhile, normal speech is between 50-60 dBA, and traffic noise is about 80-100 dBA. Noise above 70 dBA is considered loud and potentially harmful. But any impact to our hearing correlates to our proximity to the noise's source and the span of exposure.
Dr Shailendra also advises caution in our attempt to mask the unwanted noise. We may appease ourselves by listening to loud music on our earphones to drown out sound pollution, but this habit can also lead to hearing loss if taken to the extreme.
SILENCE WILL FALL
"Noise solution is considered a luxury. People only realise they have a noise problem when everything else is fulfilled," says Anuar Omar, managing director of Istiq Noise Control. "In less developed nations, people focus on needs such as food and transportation. Only when they get comfortable do they realise how noisy it is."
Anuar's company specialises in products that reduce noise pollution, mostly in industrial settings. But occasionally they would get a call from disgruntled homeowners.
"We have a case of a bungalow owner in USJ that is close to an LRT line. Every time the train passes, the noise level goes up to 80 dB. And you hear it constantly throughout the day. The owner is looking to install a noise barrier, but the cost can be prohibitive, so we suggest that he talk to Prasarana Malaysia Berhad about it."
You can sometimes see sound barriers installed along highways; high grey walls made of metal or masonry. Meanwhile, some sections of the LRT and MRT tracks have a kind of roofless tunnel, which also works to reduce noise.
The effectiveness of a sound barrier depends on its height. The higher it is, the lower the noise levels will be. But because it's in an open area, the sound cannot be reduced completely. The wall also can't be too high because you need to account for wind load and the risk of it toppling over. But it still has its detractors.
"We installed a barrier wall in a housing area in Seri Kembangan," says Istiq engineer Mohd Fariz Mohd Nor. "We calculated the ideal height for it but one resident objected because it disrupted his view. But that's the design, if you don't have it then it will be noisy."
TRADE OFF
According to Anuar, the cost of a noise barrier comes to between RM800-RM1,000 per square metre. There's a scientific formula to installing it, something like a 3x3 metre wall can reduce noise by about 20 dB. But some customers need convincing that they're not deliberately adding length or height to the wall just to charge more.
Istiq also makes doors, windows, floors and ceilings that are specially constructed for a quieter environment. These tend to be heavy — a timber acoustic door may have layers of steel inside it — because the higher the density the better the material is at blocking outside noise.
The construction also account for air gaps, because if air can get through, then so can sound. "For example, a brick wall is better than solid wood because it has a higher density," says Anuar.
"Things like sponges or foam on the wall and heavy carpeting only work to reduce internal sound. The echoes in untreated halls or mosques are due to sound waves being reflected instead of absorbed or diffused."
But if moving or renovating the home is unfeasible, stopgap measures include using thick, heavy curtains or putting rubber seals where there are air gaps. But modern life is about trade-offs, some noises you just can't live with or without.