Noise pollution in Bangladesh
Anwar Hossain Manju

As the population of Bangladesh increases, so do the processes of industrialisation and urbanisation. The number of vehicles is also increasing. Manufacturing plants are multiplying to meet the growing needs of the population. The result is an increased threat of noise induced hearing loss, annoyance and other adverse effects on the health and well being of the population. 

According to dependence on time, noise may be classified as steady, non-steady, fluctuating, intermittent impulsive, quasi-steady, ambient, etc. steady noise is a noise with negligible small fluctuations of level within the period of observation. Non-steady noise is a noise whose level shifts significantly during the period of observation. Fluctuating noise is a noise whose level varies continuously and to an appreciable extent during the period of observation. Intermittent noise is a noise whose level suddenly drops to the level of the background noise several times during the period of observation, the time during the level remains at a constant value. Impulsive noise is a noise consisting of one or more bursts of sound energy. 

A study was recently in the cities of Dhaka, Chittagong and Khulna by DOE, sponsored by World Health Organisation (WHO), to measure the extent of sound pollution, types of noise, sources of noise and exposure of noise. It specifies sensitive localities of the three cities of Bangladesh where public health is liable to be affected by noise pollution. Classification of the surveyed areas of the three cities on the basis of the level of noise pollution, comparison of observed noise level of the surveyed localities to the noise level permissible for those areas by the government of Bangladesh leading to identification of severe, moderate, mild red zone areas and green zone areas have been mentioned in the survey reports. 

Noise pollution in Dhaka city 

Forty-five localities in Dhaka city were surveyed using the sound level metro, which covered 18 generic sensitive areas which comprise silent areas like educational institutions, hospitals, mosques, temples, residential areas. 22 specific sensitive areas covering, commercial and industrial areas, busy traffic, bus or launch terminal, airport and 5 mixed areas consisting of residential, commercial and industrial areas. 

Out of 45 areas surveyed in Dhaka city, 29 showed noise level above the permissible limits accepted by DOE. According to the severity of the noise pollution they are sub-classified as severe red zone, a moderate red zone and mild- zone areas. The remaining 16 areas showed noise level fluctuating in and around the permissible limits accepted by DOE. 

The highest dB of 100 in Dhaka city was observed at Zia International Airport take off point of plane in contrast to permissible limit of 85 dB. The lowest 50 dB was observed at National Institute of Preventive and Social Medicine (NIPSOM) though the permissible limit was 45 dB. The green zone areas are also vulnerable to increasing to noise pollution beyond the permissible limits in decibel due to many factors, such as increased population, increase number of vehicles, unregulated miking, clamor from construction works and factories, etc. 

The level of noise pollution in 10 representative areas in Dhaka city has been specified as follows:

 The findings indicate that noise pollution exists in Dhaka city in an  epidemic form.

Noise pollution in Chittagong city  

Forty-five locations covering silent, residential, commercial industrial and mixed areas in Chittagong city were surveyed to determine the noise level limit. Out of 45 areas, 28 showed noise level exceeding permissible limits and 17 showed noise level fluctuating in and around the permissible noise level. In other words, 62 per cent of the surveyed areas in Chittagong city showed noise level higher than the acceptable limits. The noise level of 36 areas of Chittagong city showed a similar pattern of level compared to that of 36 areas of Dhaka. 

Noise pollution in Khulna city 

Thirty-four areas in the Khulna city were surveyed, of which 18 showed noise level exceeding the permissible limit. The highest observed decibel in Khulna city was found to be 95.6 decibel in Shiromoni BSCIC Industrial Area, where the permissible noise limit is 75.6 decibel. The lowest noise 58.60 decibel was observed in Khalishpur Residential Area where the permissible limit is 50 decibel . The finding establishes the existence of noise pollution in an epidemic form in Khulna city. 

The findings of the survey on noise pollution in the city of Dhaka, Chittagong and Khulna not only establish the existence of the grave situation of noise pollution in the three cities but also bear testimony to the perdition of ENT specialists of the country, which read as follows: 

After 20-25 years, 50 of percale of the population of Dhaka city would be losing their hearing capacity by 30 dB, of immediate steps are not taken to prevent, control and monitor noise hazard ill effects and annoyance produced by noise pollution. 

To face the epidemic situation of noise pollution it is necessary to raise people’s awareness to curb noise pollution by  focussing or reducing the use of noise in traffic. 

·        Implementation of regulations prohibiting use of hydraulic horns, as well as stopping import, and marketing of hydraulic horns.

·        Development of a multi-disciplinary hearing conservation programme involving industrial hygienist, engineer, nurse, audio-metric technician, audiologist and otiologist.

·        Reduction of noise level in the workplace by adopting engineering control methods, which include regulation of spacing between source of noise and receiver.

·        Setting of new housing, schools and hospitals away from noise areas.

·        Setting up of Traffic Police Anti-Noise Brigade by government.

·        Conduct social survey concerning feeling of public as regards traffic noise and involvement of media to support noise abatement campaign.

·        Locating highways away from populated areas and use of bypasses and circumferential routes.

·        Introduction of underground transport system in place of existing surface transport system.

 Source: Holiday, September 14, 2001