The New Nation - Internet Edition

Sheikh Arif Bulbon

Noise pollution in Dhaka city is increasing everyday where transportation vehicles and man-made din are the worst offenders, which is harmful to health.

Among the transportation vehicles aircraft, railroad stock, trucks, buses, automobiles and motorcycles all produce excessive noise.

Noise intensity is measured in decibel (dB) units. Subjected to 45 dB of noise, the average person cannot sleep. At 120 dB the ears register pain; hearing damage begins at a much lower level at about 85 dB.

In Bangladesh, noise pollution, also termed as sound pollution, is a major health hazard. In fact, due to noise pollution millions of people in the country are exposed to a number of health risks - from deafness to heart attack.

On the city streets noise pollution can be caused by hydraulic horns of vehicles, microphones and cassette players. The hydraulic horns used by buses, trucks and scooters in the crowded city streets are dangerous for human being. This is also how noise pollution in Dhaka City is affecting the hearing power of thousands of children everyday. The horns especially cause serious damage to children, said health experts.

"If a child below three years of age hears a horn emitting 100 dB of noise from a close range, he or she might lose his or her hearing power," said Dr Habibullah Talukder, Secretary General of Bangladesh Cancer Foundation.

A child's health may also be adversely affected by loud sounds from the radio, television, cassette players and microphones, the sound of mills and factories and loud noise, he said.

The unit of sound frequency is hertz. Human beings usually hear 15 to 20 kilohertz (KHz) frequency sound.

According to the World Health Organisation (WHO), generally 60 dB sounds can make a man deaf temporarily and 100 dB sounds can cause complete deafness.

But the noise of any busy street in Dhaka has been estimated at 60 to 80 dB, with the sound of vehicles being 95 dB, loud speakers 90 to 100 dB, mills and factories 80 to 90 dB, restaurants and cinema halls 75 to 90 dB, festivals 85 to 90 dB, scooter or motorbike 87 to 92 dB and trucks and buses 92 to 94 dB. But the desired sound measure is 25 dB in the bedroom, 40 dB in the dining or drawing room, 35-40 dB in the office, 30-40 dB in the class room, 35-40 dB in the library, 20-35 dB in hospital, 40-60 dB in a restaurant and 45 dB in the city at night.

When the sound exceeds this limit, there is noise pollution. Noise pollution beyond the limit destroys hearing and might even lead to the losing of one's mental balance, warned physicians.

Noise pollution also causes irritable temperament, affects lungs, hampers the intellect of the children and makes them apathetic towards their studies, they said.