noise pollution in dhaka city

Noise Pollution In Dhaka City.Muhammad Mahadi

Environmental Science Discipline

Introduction: Much discussion occurs in the media over the many serious environmental

problems that Bangladesh faces. Recently, polythene bags in particular have drawn much

attention so much so that the Government of Bangladesh banned the use of polythene shopping

bags. Air pollution is also often discussed, though measures to reduce it have been limited todate.

But what about noise pollution? While it is sometimes mentioned, it has not received serious

attention. To some Dhaka residents, it may be considered more of a necessary aggravation than a

serious problem that can be addressed.

Noise pollution is not only an aggravation, but also a serious health risk. The WHO has

established maximum allowable levels of noise, above which people are harmed; it is widely

known that in many parts of Dhaka city, those levels are regularly exceeded. Regular exposure to

high levels of noise damages hearing. Noise pollution can also increase stress and blood

pressure, cause troubles sleeping and concentrating, and lead to bad tempers and fights. Noise

pollution can also be reduced, through passage and enforcement of laws, and increasing of public

awareness about the problem and ways to reduce it.

Noise pollution continues to pose a major health threat for Bangladesh, especially in cities and

particularly in Dhaka city. People of Dhaka city mostly suffer from the bad effects of noise

pollution. Approximately 12 million people now live in the capital city where traffic congestion

is a regular phenomenon almost in every road, lane and by-lane. This traffic congestion is the

root cause of noise pollution as most of the motor vehicles especially buses, mini-buses and

trucks have hydraulic horns and the drivers are trained to honk continuously till they get their

ways clear. Other reasons for honking that creates noise pollution include reckless driving,

overtaking and drivers’ lack of knowledge on the impact of noise pollution. Moreover, use of

brick-crushing machines in the locality and abuse of loudspeakers are other causes of noise

pollution. In my discussion here I discuss about the noise pollution of Dhaka city.

What is noise : In simple terms, noise is unwanted sound. Sound is a form of energy which is

emitted by a vibrating body and on reaching the ear causes the sensation of hearing through

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nerves. Sounds produced by all vibrating bodies are not audible. The frequency limits of

audibility are from 20 HZ to 20,000 HZ.

A noise problem generally consists of three inter-related elements- the source, the receiver and

the transmission path. This transmission path is usually the atmosphere through which the sound

is propagated, but can include the structural materials of any building containing the receiver

(See Fig. 1)

Fig. 1 Inter-relationship between the elements of noise

Noise may be continuous or intermittent. Noise may be of high frequency or of low frequency

which is undesired for a normal hearing. For example, the typical cry of a child produces sound,

which is mostly unfavorable to normal hearing. Since it is unwanted sound, we call it noise.

The discrimination and differentiation between sound and noise also depends upon the habit and

interest of the person/species receiving it, the ambient conditions and impact of the sound

generated during that particular duration of time. There could be instances that, excellently

rendered musical concert for example, may be felt as noise and exceptional music as well during

the course of the concert !

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Sounds of frequencies less than 20 HZ are called infrasonics and greater than 20,0000 HZ are

called ultrasonics. Since noise is also a sound, the terms noise and sound are synonymously used

and are followed in this module.

How Sound Computed : The intensity of sound is measured in sound pressure levels (SPL)

and common unit of measurement is decibel, dB. The community (ambient) noise levels are

measured in the A - weighted SPL, abbreviated dB(A). This scale resembles the audible response

of human ear. Sounds of frequencies from 800 to 3000 HZ are covered by the A - weighted

scale. If the sound pressure level, L1 in dB is measured at r1 meters, then the sound pressure

level, L2 in dB at r2 meters is given by,

L2 = L1 - 20 log10 (r2/r1) ...... (1)

If the sound levels are measured in terms of pressure, then, sound pressure level, LP is given by,

LP = 20 Log10 (P/Po) dB(A) ...... (2)

The Lp is measured against a standard reference pressure, Po = 2 x 10-5 N/m2 which is

equivalent to zero decibels. The sound pressure is the pressure exerted at a point due to a sound

producing source (see. Fig. 2)

Fig. 2 Definition of sound pressure

Day-night equivalent noise levels (Ldn): The day night equivalent noise levels of a community

can be expressed as -

Ldn , dB(A) = 10 x log10 [15/24 (10Ld/10) + 9/24 (10(Ln + 10)/10)] ............... (3)

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where, Ld = day-equivalent noise levels (from 6AM - 9 PM), dB (A)

Ln = night equivalent noise levels (from 9 PM - 6 AM), dB (A)

The day hours in respect to assessment of noise levels, is fixed from 6 AM - 9 PM (i.e., 15 hrs)

and night hours from 9 PM - 6 AM (i.e., 9 hrs). A sound level of 10 dB is added to Ln due to the

low ambient sound levels during night for assessing the Ldn values.

Addition of sound levels: The effective sound levels form two or more sources cannot be

simply added algebraically. For example, the effective sound level from two air conditioners 60

dB(A) each, say is not 60 + 60 = 120 dB (A) but 60 + 3 = 63 dB(A). (See table 1). Similarly, the

effective sound level of 57 dB, 63 dB, 63 dB, 66 dB and 69 dB is 72 dB. The computation is

illustrated below.

Table 1 Addition of sound levels, L1 and L2 (L1 > L2)L1 - L2, dB Add to L1

0 or 1 3 dB

2 or 3 2 dB

4 - 8 1 dB

9 or more 0 dB

Source : Franken A. Peter, Community Noise Pollution, Industrial Pollution, Van Noistrand Reinhold Company, New York, 1974 ed.

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Frequency analysis : The frequency analysis allow to separate the main components of the

signals by dividing the frequency range of interest into smaller frequency bands using a set of

filters. We may distinguish between noises that consist of regularly repeated or periodic sounds

and those that consist of aperiodic sounds. The simplest periodic sound is a pure tone i.e., a

pressure disturbance that fluctuates sinusoidally at a particular frequency. The lower the

frequency, the longer is the wave length (wavelength = velocity of sound/frequency).

The noise produced by most sources of community noise, such as automobiles or aircraft

engines, are examples of aperiodic sounds. Such sounds cannot be subdivided into sets of

harmonically related pure tones but can be described in terms of components extending over

finite frequency bands. Such frequency analysis are often done in bands of octaves or 1/3

octaves.

An octave band is a frequency band with upper and lower cutoff frequencies having a ratio of 2.

The cut off frequencies of 707 HZ and 1414 HZ define an octave band, whose band centre

frequency is 1000 HZ and would be referred to as the 1000 HZ octave band.

Frequency analysers can be divided into two groups viz. constant band width analyser and

constant percentage bandwidth analyser. In the constant bandwidth analyser the filter bandwidth

is kept constant throughout the frequency range while in the constant percentage bandwidth

analyser, the bandwidth is proportional to the centre frequencies. The constant percentage

bandwidth analyser is widely used. The nine preferred centre frequencies for noise level

measurement are 31.5, 63, 125, 250, 500, 1000, 2000, 4000 and 8000 HZ.

As already mentioned, dB(A) values give emphasis to sounds in the range of about 800 to 3000

HZ. Since the sound generating frequencies are not fully covered under dB(A), for detailed

evaluation and engineering design, the multiple-number descriptions provided by frequency

analysis are often required.

Noise measurement instruments : Noise measurement is an important diagnostic tool in

noise control technology. The objective of noise measurement is to make accurate measurement

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which give us a purposeful act of comparing noises under different conditions for assessment of

adverse impacts of noise and adopting suitable control techniques for noise reduction. The

various equipment used for noise level measurement are summarised at Table 2. The principle

and the components of noise measuring instruments is summarised below.

A sound level meter consists basically of a microphone and an electronic circuit including an

attenuator, amplifier, weighting networks or filters and a display unit. The microphone converts

the sound signal to an equivalent electrical signal. The signal is passed through a weighting

network which provides a conversion and gives the sound pressure level in dB. The instructions

laid down by the noise level meter manufacturers shall be followed while using the instruments.

The time constants used for the sound level meter standards are (3)

S (Slow) = 1 second

F (Fast) = 125 milli seconds.

Relatively steady sounds are easily measured using the "fast" response and unsteady sounds

using "slow" response. When measuring long-term noise exposure, the noise level is not always

steady and may vary considerably, in an irregular way over the measurement period. This

uncertainty can be solved by measuring the continuous equivalent level, which is defined as, the

constant sound pressure level which would have produced the same total energy as the actual

level over the given time. It is denoted as Leq. The display of Leq facility is also available in

certain models of sound level meters. This is the desired parameter for assessment of ambient

noise levels.

Table 2 Equipment used in the measurement of noise levels.S.No. Equipment Specification/Area of usage

1. Sound level meter Type-0 : Laboratory reference standardType-1: Lab use and field use in specified controlledenvironmentType-2: General field use (Commonly used)Type-3: Noise survey

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2. Impulse meters For measurement of impulse noise levels e.g. hammer blows, punch press strokes etc.

3. Frequency analysers For detailed design and engineering purpose using a set of filters.

4. Graphic recorders Attached to sound level meter. Plots the SPL as a function of time on a moving paper chart.

5. Calibrators For checking the accuracy of sound level meters.

Source : Industrial Safety and Pollution Control Handbook, Associate (Data) Publishers Pvt.,Secunderabad, 1991 ed.

Sources of noise :

The sources of noise may vary according to daily activities. They sources may be domestic

(movement of utensils, cutting and peeling of fruits/vegetables etc.) natural (shores, birds/animal

shouts, wind movement, sea tide movement, water falls etc.), commercial (vendor shouts,

automobiles, aeroplanes, marriages, laboratory, machinery etc.) industrial (generator sets,

boilers, plant operations, trolley movement, transport vehicles, pumps, motors etc.). The noise

levels of some of the sources are summarised at table 3.

Typical surveys pertaining to causes of noise pollution, reveal the various sources of noise

pollution and frequency variation of their occurrences. Road traffic is identified as the major

source of noise pollution while at home or outdoors or at work.

Table 3 Typical noise levels of some point sources.

Source Noise level dB(A) Source Noise level, dB(A)

Air compressors 95-104 Quiet garden 30

110 KVA diesel generator

95 Ticking clock 30

Lathe Machine 87 Computer rooms 55-60

Milling machine 112 Type institute 60

Oxy-acetylene cutting 96 Printing press 80

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Pulveriser 92 Sports car 80-95

Riveting 95 Trains 96

Power operated portable saw

108 Trucks 90-100

Steam turbine (12,500 kW)

91 Car horns 90-105

Pneumatic Chiseling 118 Jet takeoff 120

Source : Muralikrishna, K V S G, Air Pollution and Control, Kaushal & Co., Kakinada, AP, 1995 ed.

Aircraft Noise : The noise of aircraft is described in terms of Perceived Noise Levels

(PNL), a scale of noisiness, expressed in pNdB. There is no simple relationship between the

dB(A) value and pNdB value for all noises. However, a useful statement is that, the pNdB value

for a noise is approximately 13 units greater than the dB(A) value for the noise.

A further refinement resulting from the study of aircraft noise is the Effective Noise Level, a

scale of noisiness of a time-varying event, expressed in EPNdB. It is used to describe the noise

of a single aircraft activity. In order to describe the noise exposure associated with an airport, the

EPNdB values are supplemented with such information as the number of flights of each aircraft

type, the flight paths that the aircraft use and the time of day at which the operations occur. The

resulting picture is often presented in such terms as Noise Exposure Forecast (NEF) contours,

which are intended to represent the long-term average noise exposure in communities around

airports.

Noise Pollution In Bangladesh: man-made noise harmful to health or welfare.

Transportation vehicles are the worst offenders, with aircraft, railroad stock, trucks, buses,

automobiles, and motorcycles all producing excessive noise. Noise intensity is measured in

decibel (dB) units. Subject to 45 dB of noise, the average person cannot sleep. At 120 dB the ear

registers pain; hearing damage begins at a much lower level, about 85 dB.

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In Bangladesh noise pollution (also termed as sound pollution) is a major health hazard. In fact,

due to noise pollution millions of people in Bangladesh are exposed to a number of health risks -

from deafness to heart attack. On 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. Experts say, 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. 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.

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 sound

can make a man deaf temporarily and 100 dB sound 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. Noise pollution also causes peevish temperament,

affects lungs, hampers the intellect of the children and makes them apathetic towards their

studies.

According to a survey of the Department of Environment (DOE), noise causes mental and

physical illness among the people. It causes high blood pressure, tachycardia, headache,

indigestion, peptic ulcer, and also affects sound sleep. Anyone may become deaf for the time

being if 100 dB or more noise pollution occurs for half an hour or more in any place. Working in

an atmosphere of loud noise for a long period can cause complete deafness to any person. Any

sort of noise pollution seriously affects expecting mothers. It has been observed that pregnant

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mothers living near big airports give birth to more crippled, deformed and immature children

than those living in other places.

According to the DOE the perfect sound condition for Bangladesh is 45 dB for the daytime and

35 dB for the night in peaceful areas, 50 dB for the daytime and 40 dB for the night in residential

areas, 60 dB for the daytime and 50 dB for the night in mixed areas (residential, commercial and

industrial localities), 70 dB for the daytime and 60 dB for the night in commercial areas and 75

dB for the daytime and 70 dB for the night in industrial areas.

Another survey of DOE shows that noise pollution has increased in different parts of Dhaka City.

The survey indicates that at Shaheen School the noise level is 83 dB during daytime and 74 dB at

night. At Motijheel Government High School the noise level is 83 dB during daytime and 79 dB

at night, at Dhanmondi Government Boys School 80 dB during daytime and 75 dB at night, at

Azimpur Girls' College 80 dB during daytime and 74 dB at night, at Tejgaon Girls' College 75

dB during daytime and 67 dB at night, at Bangabandhu Sheikh Mujib Medical University 82 dB

during day and 74 dB at night, at Dhaka Medical College Hospital 80 dB during the day and 69

dB at night, at Mitford Hospital 76 dB during the day and 73 dB at night and at Shishu Hospital

72 dB during the day and 69 dB at night.

City-dwellers Suffer From Noise Pollution : Although the problems of air and water

pollution have received much publicity through the print media, there seems to be a lack of

awareness in the case of noise pollution. Notably, environmental activists as well as journalists

have not been vocal enough about the adverse effect of noise pollution, which is no longer just a

minor health hazard. Despite being widespread, its long-term ill effects are somehow not obvious

to the casual observer and even trained environmentalists apparently have failed to take stock of

the situation. At present, its pernicious effects can be felt even in district towns, not to mention

big cities.

For lack of zoning laws governing growth activities in specific areas like residential,

commercial, industrial, recreational, etc., we find an intermingling of disparate entities in a given

area. For example, a predominantly residential area may have mills and factories, commercial

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centres, educational institutions etc. Hospitals, recreational areas such as parks, and libraries are

found located within areas of heavy vehicular traffic, causing serious noise pollution as the

rattling sound from two-stroke engines of auto-rickshaws and uncontrolled honking of horns by

cars, trucks and buses continue all day long.

In many cases, our lack of civic sense compounds the problem. Organisers of different functions

including marriage ceremonies and other social or political events install loudspeakers to play

music or to deliver speeches, even in the late hours of night.

They do not spare a thought that the noise they create could be a source of extreme mental agony

for people living around, particularly patients, students studying for exams or those trying to rest

after a hard day's work.

The intensity of sound is measured in logarithmic units known as decibels. Sounds measuring 80

decibels can cause hearing defects. Steady exposure to sounds exceeding 90 decibels, a level that

is frequently reached in many common urban areas during construction work involving drilling

and welding, takeoff and landing of jet planes, traffic jams, etc., can cause permanent damage to

the ear. In addition to loss of hearing, noise can produce other deleterious effects on human

health and work performance.

Developed countries are much more conscious about the adverse effects of noise pollution. In

Japan, stretches of noise insulation boards have been installed along the road from the Narita

Airport to the Tokyo City Centre in order to protect residential areas from the onslaught of noise

rising from movement of heavy motor traffic.

In many cities, operation of drills and other noisy equipment after daylight hours is legally

prohibited. Another strategy of urban planning is to locate busy city centres and heavy industries

outside city limits.

As far as we are concerned, it is not that we lack legal provisions regarding noise control in our

country. Dhaka Metropolitan Police have issued codes governing the use of loudspeakers during

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public meetings and other functions. But enforcement of these rules is another matter.

Our legal instruments available cannot be used for noise control due to the indifference on the

part of the affected quarters. Lately, the situation has reached such proportions that some are

saying that we, as a nation, are not yet fit for urban living.

In view of the growing menace of noise pollution, the onus of convincing the people about the

hazards of noise pollution and building up an effective movement to stop it lies on the doctors,

scientists, environmentalists, and journalists.

Noise pollution And Dhaka City : Level of noise in Dhaka city is now a major concern

for the general people because it has exceeded the tolerance level. According to a recent study

conducted by WHO at 45 locations of Dhaka city, most of the traffic points and many of the

industrial, residential, commercial, silent and mixed areas are suffering noises exceeding the

standard limits of Bangladesh. WHO found noise levels of 70 dB in Dhaka Medical College, 75

dB in Shakhari Patti, 90 dB in English Road, 87.8 dB in Rajuk avenue and 85 dB in Tejgaon,

though the standard limit for those area are 50, 55, 60, 70 and 75 dB respectively. WHO has also

identified several areas as severe red, moderate red, mild red and green zones in terms of noise

pollution in Dhaka city (Figure 03)

These are mainly due to vehicular horns and movement, loudspeakers from processions and

meetings, high volume of audio players from roadside small business enterprises and others (see

Figure 04, and 05.).

.

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Figure - 3. Noise Pollution of Dhaka City

Figure 04. Construction activities Figure 05. Political meeting at Jatrabari using loudspeakers

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Noise Pollution In Dhaka City : A study was conducted in 1999 in the same areas, which

had also showed almost similar findings. The noise scenarios of Dhaka city, in fact, show an

extreme threat to human health, especially for elderly people and children. Moreover, the traffic

personnel, rickshaw pullers, open vehicle drivers, road side workers, small scale business

enterprise workers etc are exposed for long-term noise pollution which might cause severe

mental and physical health problems. Details of the noise level of different zones of Dhaka city

are shown in Table 04 to 08 ,those table also discuss the exceeding limits of sound. However, an

average sound level was determined in all the above findings.

Table 04 : Noise Level in Silent Zone of Dhaka City

Name of Areas 1999(dB)

2002(dB)

I.C.D.D.R.B Hospital 76.5 65.0

Dhaka Medical College Hospital 70.0 70.0

Kakrail Mosque 70.0 70.0

Bangabandhu Sheikh Mujibur Rahman Medical University

68.9 69.0

Shaheen School 67.6 58.0

Titumir College 66.8 66.8

Temple and Church 65.5 85.3

I.P.H. Mosque 60.0 55.0

Dhakeswari Mandir at Bakshi Bazar 53.0 53.0

NIPSOM 50.0 57.0

Standard Limit forBangladesh

50 50

Source: WHO, 2002

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Table 05 : Noise Level in Residential Areas of Dhaka City.Name of Areas 1999

(dB)2002(dB)

Mirpur 79.4 63.0

Shakaripatti 75.5 75.6

Dhaka Cantonment 74.4 73.0

Dhanmondi 67.0 65.0

Banani 61.4 61.4

Mohammadpur 61.0 61.0

Gulshan 56.6 55.0

Standard Limit for Bangladesh 55 55

Source: WHO, 2002

Table 06: Noise level in Mixed Areas of Dhaka city .Name of Areas 1999

(dB)2002(dB)

Mouchak Round 92.6 80.0

English Road 90.0 90.0

Dhaka Judge’s Court 83.7 83.7

Chawk Bazar 77.8 79.0

Shakaripatti 77.5 75.5


Source: WHO, 2002

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Table 07 : Noise level in Commercial Areas of Dhaka City .


2002(dB)

Framgate 90.0 81.0

Rajuk Avenue 87.8 87.8

New market 86.4 86.3

Gulshan 86.3 82.0

Motijheel 82.0 83.0


Source: WHO, 2002

Table 08 : Noise level in Industrial Areas of Dhaka City.


2002(dB)

Inside of Nabisco,Tejgaon

89.0 85.0

Tejgaon 87.0 84.0

Hazaribagh 80.8 80.0


Source: WHO, 2002

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Those Noise Pollution Occurs Due To :

Vehicular horns: Due to traffic jams on the roads of Dhaka city, most of the vehicles use their

horn constantly, which is extremely harmful to human health, especially for children. The World

Health Organization (WHO) opines that 60 decibels of sound can make a person deaf (The Daily

Bangladesh Observer, 9 April, 2004). The noise level of Dhaka is more or the city have sound

level more than the noise quality standard.

The WHO study already identified eight areas in Dhaka city as severe red zones and ten areas as

moderate red zone for noise pollution of which Mahakhali, Gabtoli, and Sayedabad bus terminals

are on the top for extreme noise pollution. Moreover, due to lack of awareness and inefficiency

in driving, many drivers use the horn unnecessarily that increases sound level in the proximity.

The practical situation is very severe in the mornings near any primary of secondary school. The

drivers constantly blow their horns, which directly expose the students to higher level of sound.

Many vehicles with very old engines ply on the city street that sometimes create more noise than

the horns. However, proper enforcement of the following policies, acts and guidelines may able

to address the noise hazards in the city.

Environment Policy 1992

Environment Conservation Act 1995

Environment Conservation Rules 1997

EIA guidelines for industries to control the noise pollution of the city

Besides the above mentioned policies, acts and rules, recently the government has taken some

action to control noise level in the city. Some of these initiatives are as follows.

1. Formulation of Noise Control Rules, 2004.

2. Banning vehicular hydraulic horns.

3. Monitoring mechanism at the main traffic points to determine whether the vehicles

follow the orders or not.

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4. Removal of 4000 nos. of hydraulic horns by the DMP from the vehicles plying on the

city street (Hasan, 2003).

5. Tejgaon truck terminal would be relocated to a nearby place belonging to the

Bangladesh Railway, which might save large parts of Tejgaon and Kawranbazar from

severe traffic congestion and hence noise pollution.

6. The decision to relocate the Gabtoli, S a i d a b a d , Armani t o l a and

Mohammadpur truck terminals has also been taken which would reduce the noise

level in those areas.

7. The decision has been made to relocate most of the bus stops, demolish passenger

sheds and build new ones at suitable places.

Industrial Operation: A large number of industries are located in three specific areas, though

some are sited in a scattered manner in different parts of the city. Tejgaon and Hazaribagh are the

major industrial areas of the city, which are identified as red zone for noise pollution. In fact, all

these industrial sites are located very close to the major roads of the city. So throughout the day,

transport noise and the noise of industries usually occur together. In Tejgaon industrial area, the

sound level was found 87 dB in 1999 and 84 dB in 2002, which shows that the sound level

exceeded the standards by more than 10 dB in just 3 years. In Hajaribagh, the noise level was

measured to be 80.8 dB in 1999 and 80 dB in 2002; both had exceeded the standards. It has been

reported that about 16,000 people work in the Hazaribagh tannery industries with continuous

exposure to chemicals and noise (Khan, 2003). Besides the workers, many nearby residents,

professionals, school children, and medical patients are also highly exposed to this combined

noise effect of industry and transport vehicles. However, the industries of the city may be

compelled to comply with the above policies and guidelines with a view to reducing the noise

level. Enforcement and monitoring on industrial operation is also needed on an emergency basis.

Construction and Repair Activities : The rapid urbanization, economic development and utility

management of the city include construction and reconstruction of residential buildings,

commercial buildings, roads and highways. All these development activities require brick

grinding machines, forklifts, metal equipments, generators etc. that create huge amounts of noise

during their operation. These activities have tremendously increased in last few years in the city.

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Besides these, there are a large number of metal workshops on the roadsides, which use metal

instruments for cutting and shaping, as necessary. The continuous hammering activities have

extreme effect on everyday life and can cause mental disorder in the people living in close

proximity of the sound. Such noise should be controlled by enforcing the above rules and

policies.

Use of Loudspeakers and Microphones: The most uncomfortable situation for city dwellers arise

when the use of loudspeakers in the shops and markets and microphones for political processions,

meetings, picnic parties, lottery ticket selling etc goes beyond human tolerance.

Such nuisance and unnecessary use of microphones and loudspeakers are observed mainly in the daytime

all over the city, which seriously bother the city dwellers. Students can hardly concentrate in their studies

due to the regular blare of microphones in some areas of Dhaka city. Most of the commercial and

administrative areas including Motijheel, Farmgate, and Rajuk Avenue have exceeded the standard limit

(WHO, 1999 & 2002). Motijheel and Farmgate were identified as red zones in terms of noise pollution

due to the loudspeakers used for selling lottery tickets, for political, social, religious and organizational

meetings and processions. Such tremendous levels of noises disturb the people in those areas and may

also cause mental and physical illness. The health section of the Environment Policy of 1992 strictly

states the need for developing healthy environment for urban areas to ensure healthy workplace for

workers (BELA, 1996). Upcoming noise rules may be used to address this situation.

Vehicular movements on uneven/bumpy road surface : Much of the city road surface

including major roads, link roads, and lanes and by-lanes are not smooth or clean enough for

efficient transportation. Moreover, most of the city roads are frequently dug up for construction

activities by the different utility services, and in many cases, the reconstruction job of the road is

not properly completed. As a result, the road surfaces become uneven, patchy and bumpy, which

in turn causes continuous friction with running vehicles. Following are the necessary actions

required to overcome the situation:

• Effective coordination between relevant organizations

• Completion of assigned construction or reconstruction of roads activities

• Frequent digging up of roads

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Road surface should be smooth and even otherwise it causes noise and accidents too. Continuous

bumping on uneven road surface also reduces longevity of the vehicles.

Effects Of Noise Pollution :

Effects on the Ear

Deafness

Temporary Deafness: This Persists for about 24 hours after exposure to loud

noise.

Permanent Deafness: Repeated or continous exposure to noise of around 100 dB

results in permanent hearing loss.

Even single exposure to noise of 160 dB can lead to rupture of ear drum and

permanent deafness.

In cases of long term exposure to moderatly loud noise, the onset and progress of noise

induced deafness is very gradual and by the time the individual is already somewhat deaf,

he/she many not be aware of the deafness until the deafness starts affecting the person's

ability to hear normal conversation, telephone rings and doorbells etc.

Auditory Fatigue

Noise of 90 dB causes buzzing and whistling in the ears.

Effects on other systems

Decreased Work Efficiency

With increasing noise, efficiency of work decreases because of disturbed concentration,

annoyance and early onset of fatigue.

Increased Intracranial Pressure

(Fluid Pressure of the Cerebro Spinal Fluid, the fluid present inside the cavites of brain

and between brain and skull)

This leads to Headache, Nausea and Giddiness.

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Increased Blood Pressure

Noise can very effectively raise the Blood Pressure of even a normal person.

Increased Heart Rate, Respiration rate and Sweating.

Diminished Night Vision, Colour Perception and visual disturbances.

Noise Control at Source : The noise pollution can be controlled at the source of generation itself by employing techniques like-

Reducing the noise levels from domestic sectors: The domestic noise coming

from radio, tape recorders, television sets, mixers, washing machines, cooking

operations can be minimised by their selective and judicious operation. By usage

of carpets or any absorbing material, the noise generated from felling of items in

house can be minimised.

Maintenance of automobiles: Regular servicing and tuning of vehicles will

reduce the noise levels. Fixing of silencers to automobiles, two wheelers etc., will

reduce the noise levels.

Control over vibrations: The vibrations of materials may be controlled using

proper foundations, rubber padding etc. to reduce the noise levels caused by

vibrations.

Low voice speaking: Speaking at low voices enough for communication reduces

the excess noise levels.

Prohibition on usage of loud speakers: By not permitting the usage of

loudspeakers in the habitant zones except for important meetings / functions.

Now-a-days, the urban Administration of the metro cities in India, is becoming

stringent on usage of loudspeakers.

Selection of machinery: Optimum selection of machinery tools or equipment

reduces excess noise levels. For example selection of chairs, or selection of

certain machinery/equipment which generate less noise (Sound) due to its

superior technology etc. is also an important factor in noise minimisation strategy.

Maintenance of machines: Proper lubrication and maintenance of machines,

vehicles etc. will reduce noise levels. For example, it is a common experience

that, many parts of a vehicle will become loose while on a rugged path of journey.

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If these loose parts are not properly fitted, they will generate noise and cause

annoyance to the driver/passenger. Similarly is the case of machines. Proper

handling and regular maintenance is essential not only for noise control but also

to improve the life of machine.

Conclusion : Noise pollution is a serious and neglected issue in Dhaka, and throughout

Bangladesh. It is time for NGOs, the media, and the Government of Bangladesh to work together

to reduce the problem, and increase the quality of life in this country. As many of the sources of

noise pollution are unnecessary and could be reduced fairly easily and at little cost, there is no

excuse for further delaying on action. Given the magnitude of the problem, and of the human

suffering that results, we can no longer afford to neglect the issue of noise pollution. For the

health, sanity, and well-being of the population, and for the future of our children, it is time that

we all take this problem seriously, and begin implementing solutions. Whether as individuals,

NGO staff, or members of the media, we can and must take specific steps to reduce the problem

of noise pollution.

Noise Pollution In Dhaka City.Made By-=-

Muhammad MahadiEnvironmental Science Discipline

Khulna UniversityKhulna.

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References :

i. Assessment and Control of Noise Pollution in Mining Industry,

Proceedings of National Seminar held by Institution of Engineers at

Madras, 1989.

ii. Environmental Noise Pollution and its Control, Proceedings of Specialist

Course, Institution of Engineers, Roorkee, India 1992.

iii. Industrial Safety and Pollution Control Handbook, Associate (Data)

Publishers Pvt., Secunderabad, 1991 ed.

iv. Muralikrishna, K V S G, Air Pollution and Control, Kaushal & Co.,

Kakinada, AP, 1995 ed.

v. Rao, P.R., Noise Pollution and Control, Encyclopedia of Environmental

Pollution and Control, Vol.-2, Environmedia Publications, India, 1995 ed.

vi. Jeva, R. et al, Noise Impact Assessment - an approach, Energy

Environment Monitor, Vol.: 12, September 96.

vii. Mathur, J.S.B., Noise Control : Legislation, Planning and Design,

Industrial Effluent Treatment, Vol.:2, Applied Science Publishers Ltd.,

London, 1981 ed.

viii. Mathur J.S.B., Noise Control : Methods of Reduction, Industrial Effluent

Treatment, Vol. : 12, Applied Science Publishers Ltd., London, 1981 ed.

ix. Franken A. Peter, Community Noise Pollution, Industrial Pollution, Van

Noistrand Reinhold Company, New York, 1974 ed.

x. Puplic republic of bangladesh ,Depertment of environment and forest web

site paper.

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noise pollution in dhaka city

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