In search of si­lence

Ur­ban noise pol­lu­tion is mak­ing us deaf and killing us slowly, writes Aznim Ruhana Md Yusup

New Straits Times - - Heal - aznim.ruhana@nst.com.my

ILIVE 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 liq­uid­filled 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

You don’t con­sider noise as some­thing bad be­cause you’ve been ex­posed to it all your life. But it’s be­cause you’ve been ex­posed to it that it af­fects you.

Dr Shailen­dra Si­valingam

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 home-

own­ers. “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.

Photo by Zul­fadhli Zulkifli.

A morn­ing snapshot of traf­fic in the Klang Val­ley. No­tice the wall be­tween the high­way and hous­ing area.

PHOTO FROM FREEPIK.COM

The ef­fect of ur­ban noise pol­lu­tion is both au­di­tory and ex­tra-au­di­tory.

PHOTO BY OWEE AH CHUN

“Noise so­lu­tion is con­sid­ered a lux­ury. Peo­ple only re­alise they have a noise prob­lem when ev­ery­thing else is ful­filled,” says Anuar Omar.

pic­ture from freepik.com

Doc­tors warn that the habit of lis­ten­ing to loud mu­sic to drown out sound pol­lu­tion may in­stead cause hear­ing loss.

Is­tiq Noise Con­trol com­pany makes doors, win­dows, floors and ceil­ings that are spe­cially con­structed for a qui­eter en­vi­ron­ment.

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