NOISE POLLUTION MODELLING IN DHAKA CITY: A GIS APPROACH

NOISE POLLUTION MODELLING IN DHAKA CITY: A GIS APPROACH

Chapter One

NOISE POLLUTION MODELLING IN DHAKA CITY: Environment is where we live and development is what we do. These words sounds so simple, but the voyage of these two related aspects hasn’t been so simple and nor it will be if men fail to realize the value & importance of environment and the ways of sustainability as well. At present, the world-issues related to environment is growing importance day by day Man’s perception and awareness about environment has gradually been heightened in recent years as he is facing many problems with the environmental changes.

The speed and nature of environmental change (particularly man-induced change) in recent years have brought about a series of environmental problems of global magnitude-including population expansion, energy resources and utilization, the provision of food supplies, exploitation of raw materials, and environmental pollution .So drastic and quick have been the changes that Dasmann has perceived that “the human race is like an ape with a hand-grenade. Nobody can say when he will pull the pin.” (Quoted by park, C.C. 1978).

All natural eco-systems were balanced and unaffected by man until the dawn of the civilization. But the speed and nature of man-induced environmental changes have brought an increasing disharmony between him and the nature at present. Living beings are dependent upon nature for their requirements. Hence the purity and balance of environment is essential. Some of the problems such as- depletion of resources, soil erosion, pollution, deforestation and extinction of wild animals due to increased human population have reached global level.

Man has played a very important part in shaping his environment. He has been responsible for degrading the quality of his environment ever since he appeared on this earth.

1.1 Statement of the problem

In the present age of industrialization and urbanization, noise has become not just an adjust, but permanent part of man’s life. Noise pollution is one of the most harmful pollution. It is an unwanted, unpleasant or disagreeable sound that causes discomfort. Noise is any undesired sound and by extension, noise is any unwanted disturbance within a useful frequency band, for example undesired electrical waves in a transmission or device. Noise is an erratic, intermittent or statistically random oscillation. Since these definitions of noise are not mutually exclusive it is usually necessary to depend upon context for the distinction (Alberti, P .W. 1987).

Noise thus has physical, physiological, and psychological connotations, all of which differ from one another. Physically it is complex sound having little or no periodicity. However, it can be measured and its characteristics analyzed. Physiologically, acoustically and electronically, noise is defined as a signal that bears no information and whose intensity varies randomly in time. Psychologically noise is any sound, irrespective of its waveform, which is unpleasant or unwanted (Alberti, P.W. 1987).

Noise, like any sound is defined in terms of its duration, frequency spectrum (measured in H_z) and intensity measured in sound pressure level (S.P.L) and expressed in decibels (dB). It may be continuous, intermittent, impulsive or explosive. It may be steady- state or fluent.

Harmful sound becomes more pervasive and more intense in urban settings where transport and industrial sources have particularly high nuisance values. Dr. Alan Bell (WHO) has recently pointed out that noise is much more severe than an occupational hazard. It is a public nuisance and danger to mental and physical health. But in the modern age noise is no more an occasional adjusts; it has become permanent part of human life. This harmful sound known as noise becomes more pervasive and more intense in urban settings where transport and industrial sources have particularly high nuisance value. So in present days city dwellers are compelled to face many kinds of harmful effects induced by noise.

In every city of the world, the early morning tranquility is shattered by the shrill pressure horns of vehicles like trucks, buses, scooters, motor cycles, and the drivers always pressing the horn out of habit than necessity. As the city gradually awakens all kinds of noise pollutants take to the air, traffic pick up. Factories in residential areas start operations. Radios and transistors blare out the AIR milieu. Motor workshops in the midst of localities start dent beating and hammering.

As the day rises, the noise level in the different parts, of the city increases in and around work places and homes. The peak noise levels are reached in the twilight hours as traffic reaches a peak. Political processions add more with it. In offices also there is noise pollution due to clicking of typewriters, bells, ringing telephones, clattering office machines and conversations. They produce tantrums, headaches, fatigue and even nausea. On road we have noise pollution due to growling automobiles, squealing tires, screeching brakes, screaming sirens, blaring telephones and radios, blasting horns, whining jets and pounding jackhammers. Add to these metabolic sounds, loud mouths, and noisy gaits make our environment noisier.

In industrial zones noises associated with manufacturing. Noises are created with many kinds of construction works. Aircraft, due to their increase in size and enormous increase in numbers, have become one of the most troublesome sources of noise pollution. The scream of jet engines is not conductive to tranquility and repose. In some locations, conversations stop every few seconds, television viewing and listening becomes impossible, and sleep and relaxation are interrupted. This condition is multiplied many times throughout the country and the world.

Acute exposure to intense noise may temporarily impair heaving; while repeated occupational exposures to high levels can cause permanent deafness. Increased noise levels are also associated with cardio-vascular, endocrine, respiratory, neurological and psychological changes. Some of which are indicators of increased stress.

Noise pollution is assuming increasing dimensions with increase in the number of vehicles and urbanization in many parts of the world as well as in Bangladesh. In Bangladesh, Dhaka is the most vulnerable place for noise pollution. Because, in Dhaka there is a large number of vehicles, industries, markets, offices, and population with their many kinds of noise making activities.

1.2   Aims & Objectives

Dhaka is becoming a vulnerable place of noise pollution since last two decades. Noise is apparently increasing its dimension with the increases of the number of vehicles, industries and urbanization. Now this has become a permanent part of man’s life. Violent noise can cause many kinds of damages to the human health. As a vulnerable area in terms of noise pollution of Dhaka City, Ganabhaban & adjacent area has been taken as the study area to understand the status and magnitude of noise pollution in an important area. More over parts of this area is full of trees & plants which can have a correlation with mitigating the effects of noise.

The overall study objective was to produce a noise model in Dhaka City using GIS approach, particularly having the study area as Ganabhaban & adjacent region. This would serve as a strategic planning and noise reduction tool.

With a view to achieving this overall objective it is concluded that eventually a noise pollution modelling should:

1. Examine and identify the present level of noise pollution of the different points and important places of the study area providing information of noise pollution level status.
2. Determine the quantity of vulnerable institutions in the different influence zones of noise pollution of the study area.
3. Determine the role of vegetation cover as mitigating agent of noise pollution.
4. Generate isoline maps of noise level of the study area in such a way which would be able to determine the influence zones of pollution and to determine the role of vegetation cover as mitigating agent of noise pollution.

Along with these major objectives, there is an auxiliary objective also, that is to realize the people’s perception about noise pollution.

1.3   Survey of the literature

During the last two or three decades literatures have been accumulated on noise pollution in the context of some developed and conscious countries of the world. In Bangladesh the problem of noise pollution became a considerable issue only very recently. So here in this country there is a lack of literature related to noise pollution.

However, noise is gaining importance as a cause of environmental pollution in major cities of the world Dhaka is no exception. Related to the source of noise pollution, a study was conducted by Zaidi (1989). He found that 55% of noise came from motor vehicles, 20% from construction work and workshop garage and 14% from metal industries.

He also found that among motor vehicles, auto-rickshaw ranked first (52%) as a contributor to noise production. In order to save on fuel cost, auto-rickshaw drivers use higher proportion of lubricant to petrol, thus producing the menace of carbon-loaded fumes. Zaidi also found that noise produced by auto-rickshaw ranged between 100-140 dB. Noises that are harmful for health and well being have also encroached on the community. However this kind of problem created by auto-rickshaw has been controlled to some extent by introducing CNG driven auto-rickshaw.

Tripathy (1999) provides a fairly comprehensive treatment of the subject-noise pollution. He mainly focused on the prevailing atmosphere in Indian mines. Yet his descriptions are highly valuable for general readers as well as researchers as those deals with fundamentals of noise, mechanism of hearing, effects of noise on human body and mind, noise measurement and noise survey. He also focused on primary needs of the researchers whose subject area is “Noise Pollution”. To discuss the problem “noise”, he started with some fundamental subjects such as characteristics of sound, pitch, frequency, wavelength, amplitude, loudness, sound pressure, intensity, sound units, definition of noise and noise pollution etc.

Tripathy (1999) mentioned many kinds of sources of noise pollution with special reference of source of noise in mines. In this context he gave some important tables of the sources of noise pollution with their sound level value. He also mentioned some important noise measuring instruments and their measurement technique, principal and maintenance. Tripathy (1999) discussed the noise survey methods in mines with intense care. Most importantly he mentioned some relevant noise control techniques. He also mentioned noise standards of a few countries.

Srivastava, Y.N. (1995) discussed noise pollution along with other pollution of cities as they are noisy places. Noise pollution imbibes itself a serious threat to the quality of mans environment. In this regard, he has mentioned   physical discomforts and damages caused by noise. He has cited some physical responses at different levels of noise. To describe the health hazards of noise pollution he has noted that noise not only interferes with communications but also affects our peace of mind, health and behavior.  Srivastava (1995) has also mentioned the main sources of noise pollution. The most important part of his paper is noise pollution control. He has showed some relevant measure to minimize noise.

Alam, M.S. (1989) has also noted some important measures to control noise, such as emphasizing on producing of low sound creating engine for all kinds of transport. In this regard he has given the example of the technology of U.S. army and navy, as they successfully produced and used low sound creating engines. He also mentioned the usefulness of proper engine covers to control noise and ear plug to protect noise. Alam (I989)) has given a good description about the fundamental subjects of noise and harmful effects of noise pollution. He has also cited what should be the role of government to control noise.

Kudos, V. P. (1990) has given a nice statement of the problem ”Noise pollution”. He described some fundamental issues related to noise pollution and has given a noise figure which shows the various sources of noise pollution and their effect. Thay are also given two other important tables by which we can get information about threshold of hearing for young healthy ears as a function of frequency response characteristics.

The tables are bearing information about acceptable noise limits for working areas, estimated community response to noise, Swiss proposal about noise levels, number of fatal accident due to noise in India and noise levels in different cities of the world. He has given some suggestions to control   noise pollution.   Kudos (1990) cited important information about the effects of noise pollution over human health.

Alberti, P.W. (1987) mainly emphasized on health hazards of noise pollution. First of all, he has given some important definitions of noise in different points of view and also mentioned historical consideration of noise pollution. He showed the sound stimulation. Alberti, (1987) has given a very large and elaborate description of the effects of noise pollution on human health. He has given a vast statement of all kinds of auditory and non-auditory effects of noise pollution.

To describe auditory effects of noise pollution, he cited NIHL, NITTS, NIPTS, Tinnitus, acoustic injury, hair cell injury etc. To give a statement about non-auditory effects he included; illnesses, arousal in adults, sleep difficulties, mental problems induced by noise and many oilier problems. In his paper he mentioned some important things like; infra sound, ultra sound, vibration etc. He has cited some methods of personal protection from noise pollution.

Mer, Y.N. and Bissau, S. (1987) emphasized the effects of noise pollution on human health in their statement. They mentioned auditory and non-auditory effects of noise pollution. They have given some suggestions about remedial measures of noise pollution. Kumar, R (1987) has mentioned the effect of noise pollution on human health in comparison with rural quiet life. He cited that noise pollution poses quit a different problem for urban settings.

Shaha, SK (2000) has given a nice and brief statement of noise pollution problem. He included some important and relevant definition of noise pollution in his essay. He noted some synthesized effects of noise pollution. Paul, N.K. (I999) described the relation between urban health and noise pollution. He quoted that in a recent study it has been observed that as a result of noise pollution the amount of milk production from cows has been decreased. And it is also observed that noise pollution has ill effects over physical growth of some animal. Islam, B (2000) has given a statement of the severity of noise pollution in urban areas and has given some suggestions too.

His essay can be rather considered as a brief general description of noise pollution. Akhter, K.S (1998) mentioned the impact of noise pollution over hearing ability. She quoted a finding of a study which was organized in Britain, that killing instinct can be stimulated by noise pollution and in Britain 5 percent of the homicide per year are occurred due to this reason. Gupta, P (1964) has noted the effects of low frequency sound on human health.

A research work related to the noise pollution of Dhaka City has been accomplished by Chakraborty, M.R. (1999). In his report he has given the sound level data of a few cities. Hasan emphasized in his study on hearing impairment of auto-rickshaw drivers due to noise pollution.

DOE (1997) organized a study to find the status of noise pollution of Dhaka City. They have collected sound level data from 20 important points. In table, they have presented the data quite nicely. They have also provided the highest and the lowest average data in that table. They are also conducted a questionnaire survey and provided the relevant data.

Shahnaj, K. (1999) has given her statement about noise pollution as a health hazard. In her discussion she mentioned how noise pollution of Dhaka City affects the city dwellers and in this regard she emphasized on child health. She has quoted some sound level data provided by DOE (1997).

Haider, M.I. (1997) studied the environment of Tangail city. As a part his work he has mentioned the condition of noise pollution of Tangail city. Disaster report of Bangladesh (1998) has given a general description about noise pollution.

Agarwall, S.K. (1991) worked on automobile noise pollution. He mentioned how automobiles act as a source of noise pollution. Andrews, W.A. (1972) has given some ideas for thought and research about noise pollution.

Haq, Mohammad Ahsanul (2000) conducted a study on noise pollution of Dhaka City. He investigated the vulnerability of noise pollution in Ramna Thana as the study area. He generated a noise level contour map which could successfully show the vulnerability in the study area. It was one of the pioneer initiatives of making a noise map using GIS approach. He also examined the ill effects of noise pollution on a number of victims.

Iqbal, Kazi Farhed (2007) investigated the different aspects of noise pollution in Dhaka City. In his study, he emphasized on Dhaka University area mainly. He has successfully presented much information in this context.

Mahadi, Md. (2005) produced a paper on noise pollution in Dhaka City. In his paper he mainly interpreted the study conducted by World Health Organization (in 2002, at 45 points) on noise pollution of Dhaka City. He has also focused on some basic issues in this regard.

According to a study provided by Bangabandhu Seikh Mujib Medical University, hearing ability of Dhaka city dwellers has been reduced in the last 10 years. About 5% to 7% of the patients admitted to University hospital is suffering from noise induced hearing loss (Tanvir Ahmed, et al, 2004). Another study (2007) especially on “Noise induced hearing Loss (NIHL)” in Sahbagh area has been conducted by the Department of Environmental Science of Jahangirnagar University, reported that about 10.3% of the people in this area are suffering from noise induced hearing loss (Rajesh Roy, 2007).

And there are evidences of behavioral or psycho-physiological changes among street hawkers in the area. Rahman, Md. Arifur, et al (2008) discussed about noise mapping. They presented the aspects of noise mapping nicely. They conducted the study in Shahbag area.

Some of the above mentioned literatures related to noise pollution of Dhaka city provide useful information in this regard. But those works do not provide enough information about the vulnerability of the different influence zones of noise pollution of Dhaka. Those works didn’t aim at producing a model of noise pollution in Dhaka City at all and at the same time didn’t investigated whether vegetation cover have any mitigating effect on noise pollution any way. This indicates the relevance to research interventions in this context and related issues.

1.4   Relevancy of the work

Noble prizewinner German microbiologist Robert Koch said, “A day will come when man will have to fight merciless noise as the worst enemy of health” .He added more “Noise like smog agent of death” (cited in the report of DOE,’97).

Noise is very harmful for environment at the same time for human health. According to Dr.S.K. Shaha the most dangerous effects of noise pollution on human can be mentioned as follows:

1. It affects human health, comfort and efficiency. It causes hypertension, makes the skin pale, and leads to excessive secretion of adrenaline hormone into blood stream that is responsible for high blood pressure.
2. It causes muscles to contact leading to nervous breakdown, tension and even insanity.
3. It increases rate of heartbeat, digestive spasms and dilation of pupil of eye.
4. It affects health efficiency and behavior. It may cause damage to heart, brain, kidneys, liver and psychological and pathological disorder such   as;   hypertension, insomnia and emotional stress.
5. Prolonged exposure to high-pitched noise causes hearing loss.

Dr. Alan Bell (WHO) has recently pointed out that noise is much more severe than an occupational hazard. It is a public nuisance and a danger to physical health (Shaha, S.K. 2000). So a serious view of the increasing noise pollution must be taken to assess the correct situation and to take appropriate measures to protect people from hazard of noise.

But in Bangladesh very little attention is paid to control noise and a poor number of research works has been done related to this field. So there is a huge research gap in this particular subject. Dhaka is the most vulnerable place for noise pollution in Bangladesh, because of having a large number of industries, vehicles and inhabitants with their many kinds of tools that can produce noise. For this reason Dhaka should be focused first in case of the discussion of noise pollution.

Most of the literatures related to noise pollution in Bangladesh, tried to focus the present state of noise pollution in Dhaka City and some other cities. And some other literatures in this context tried to determine the effects of noise pollution over human health. However, those are not enough to realize the whole situation of a bigger city like Dhaka. More and more investigations and intensive studies at micro level are required to draw a generalized picture at macro level.

A modelling can be able to add valuable part in this context. Moreover, a modelling of noise pollution using GIS approach would be realistic enough to explore the exact situation and this kind of approach is easily understandable and would be a handy tool for policy makers. A series of modelling at micro levels would be effectively capable of producing a desired generalized picture of the noise pollution of the entire Dhaka City.

Ganabhaban and adjacent region has been chosen as the study area of this research because, it is one of the most important parts of Dhaka City. Important residences, organizations, offices, hospitals, educational institutions, park, etc. are situated here in this area. Moreover, important roads regarding national connectivity are also passes through this area. Specially, honorable Prime Minister’s residence (Ganabhan) made this area more important. Because of these effective reasons many kinds of activities are being practiced here in this area and many people come here to participate in many types of activities like; administrative tasks, business, jobs, medical support, education, conference, trade expo, travelling etc.

Therefore, a large number of vehicles are seen on the roads for transportation purpose. This situation leads the area to be one of the most vulnerable areas of the city in terms of noise pollution. So, in the view point of the importance and vulnerability of the area it deserves an intensive study. The study results would produce a clearer picture of noise pollution status of this area and would be helpful for the policy makers to deal with the situation as well.

1.5 Methodology

This particular study mainly depended on primary sources of data. Primary data were collected through different processes. The processes were as mentioned below-

Sound level data collection.

The sound level data were collected from different points and vulnerable institutions, which were selected according to the importance and vulnerability. Data were collected from different points as well as 25 meter apart from those points (most of the time) to determine variation of the influence of noise and to achieve representative mean value. The data collection process conducted in three-week days along with a holy day in every week over a month. Data collection process continued from 9 a.m. to 8 p.m. in three shifts in each day. To determine the average sound value of the noise pollution, readings were taken repeatedly after certain interval.

The data in every location were taken at three specific times of the day and they are:

•  9am to 11am
•  12pm to 4pm
•  5pm to 8pm
•  The data were taken in two different days situations:
•  Working days data
•  Holidays data

Weighting: A-weighted sound levels were measured during the study. The “A weighting”     characteristic is simulated as “Human Ear Listening” response.

A location map and a sound level meter were always carried during the data collection. A digital sound level meter was used to record the sound level. The sound level data for different location for different specified time of a day were collected. The roadside sound level data were taken by standing on the roadside. Any kind of noise barriers, bad weather, were avoided for measuring the actual sound level produced by the vehicles and other sources. Several numbers of readings of sound levels were taken by the sound level meter. All the data were recorded in computer for mapping and analysis.

Noise Measuring Instrument

A portable and digital sound level meter (model-Lutron-SL-4010) has been used to collect the data. The sound level meter is built in the internal “External calibration VR” on the front panel.

Measuring Procedure

1. Sliding the function switch to “1” makes the meter to power on position.
2. Determination of proper measuring range is done by selecting the “Range switch”.

It is done by following the indication of upper & lower range indicator in the left corner of the LCD monitor, which shows the dB range selection is upper or lower setting and indicates the user to slide the “Range switch” to other range for measuring.

3. Holding the instrument in hand and point the microphone at noise source in a horizontal position makes the meter capable of displaying the actual sound level of the source in the LCD monitor on dB unit.
4. During the measurement, the switch on “Hold” position will freeze the displayed value and the switch on “1” position will display the continuous measurement.
5. Strong wind (over 10cm/sec) striking the microphone can cause misreading for measurement in windy locations; a windscreen should be used in front of microphone.

Duration of measurement

The data collection process conducted in three-week days along with a holy day in every week over a month. Data collection process continued from 9 a.m. to 8 p.m. in three shifts in each day. To determine the average sound value of the noise pollution, readings were taken repeatedly after certain interval.

Data Standardization

Several sound level data were taken at each location points and after that, they were averaged to get the final value for sound level. The data was averaged because the sound level of a place varies due to different types of sources such as traffic signal, honking, crowd etc.

Data analysis and presentation

For data analysis and presentation various GIS (Arc view 3.2a and Arc GIS 9.2) software were used. Isoline and surface were generated on the basis of noise level data, which has been collected from the different points and important places of Ganabhaban & adjacent area. Isoline contours were produced at the interval of 3dB. Different colors were used in certain maps to indicate different noise levels. The isoline clearly depicts the spatial variation of noise. The co-ordinate system projection was BTM. For tabular data analysis and presentation MS-Excel software were used.

Questionnaire Data collection

A questionnaire survey was conducted to understand the peoples concern about noise pollution and their physical and mental reaction to noise pollution. The questions were structured in a very straightforward way to get both descriptive and measurable information. Purposive random sampling is followed in performing the questionnaire survey.

1.6   Organization of the study

The various topics in the study correspond approximately with their chronological treatment. Chapter-1, the introductory chapter has been framed to provide statement of the problem, aims and objectives, including a short literature review on noise pollution. This chapter also deals with study methods projecting objectives to be worked with, methodological aspects of data collection, handling and analysis. In addition, various adopted procedures in generation of data are also mentioned.

Environment, environmental pollution and noise pollution related fundamental issues are discussed in chapter-2. This gives a generalized idea of noise pollution its sources and classification. Sound measuring instrument, mechanism of hearing and most importantly effects of noise pollution on human health is also mentioned in this chapter.

Location, socio-economic condition, establishments, institutions, transportation system and residential areas of the study area is discussed in chapter-3. A brief discussion on different species of vegetation covers of the study area has also been mentioned here.

Chapter-4 presents analysis of data, examining the nature and effects of noise pollution in the study area. All kinds of primary data are analyzed and presented here. This chapter gives the information about the state of noise pollution in the study area both in working day and holiday. Ten isoline maps based on noise levels (of different aspects) are produced in this chapter to generate an overall model of noise pollution.

Two other maps showing the different levels of noise (of different days) in bar diagrams are also presented to clarify the condition of fluctuations. The role of vegetation as mitigating agent of noise pollution has been discussed and analyzed in this chapter. State of noise pollution in hospitals and schools is also included. In addition, people’s opinion about different aspects of noise pollution is presented here.

Chapter-5 provides a sum-up of the study including research findings, problems and future research.

Chapter-3

Ganabhaban and adjacent region is the study area of this research, it is one of the most important parts of Dhaka City. Important residences, organizations, offices, hospitals, educational institutions, park, etc. are situated here in this area. Adjacent major roads are playing important part in national connectivity. Specially, honorable Prime Minister’s residence (Ganabhan) made this area more important. As a result, many kinds of activities are being practiced here in this area and many people come here to participate in many types of activities like; administrative tasks, business, jobs, medical support, education, conference, trade expo, travelling etc.

Consequently, a large number of vehicles are seen on the roads for transportation purpose. This situation leads the area to be one of the most vulnerable areas of the city in terms of noise pollution. So, in the view point of the importance and vulnerability of the area it deserves an intensive study and the results would produce a clearer picture of noise pollution situation of this area and would be handy for the policy makers to deal with the situation as well.

3.1 Location

Ganabhaban & adjacent area situated in the ward number 40 of Dhaka City Corporation. The study area is mainly part of Agargaon & Sher-e-Banglanagar area that is mid-northern part of Dhaka City. The location can be clearly viewed from the study area map(Map-1: The Study Area).

3.2 Socio-economic Condition

Most of the people are engaged with tertiary economic activities. Government service holder, private service holder, doctors, teachers, military personnel, many types of businessman, nurses & medical personnel, hawkers and rickshaw-pullers do their activities here.

3.3 The Establishments and Institutions

The establishments and institutions are mentioned below-

Ganabhaban (Honorable PM’s residence)

Ganabhaban is the official residence of the Honorable Prime Minister of Bangladesh. It was constructed as a part of National Assembly Complex. The decision to construct National Assembly Complex at Dhaka was originally taken in 1959 (Banglapedia).

Louis I Kahn, one of the greatest architects of the time, was initially selected for designing the National Assembly complex. He was not commissioned out-right but was asked to present preliminary ideas for the complex and in March 1962 he was formally commissioned for the job. A sprawling area of 208 acres of land to the north of present Manik Mia Avenue was acquired in 1961 for the project of the second capital and the master plan was ready in 1962. The construction started in 1964 with an initial estimated cost of about $15 million (Banglapedia).

The construction of the complex along with all services and facilities was completed in 1982 at a revised cost of $32 million. The complex includes the National Assembly Building, hostels for members of parliament, ministers and secretaries, hospitality halls and community buildings all linked by roads and walkways and surrounded by attractive gardens and lakes.

The changes in the original master plan mainly involved location of Supreme Court, a Grand Mosque and the President’s Palace. Efforts were made to make the palace as inconspicuous as possible and these were moved away from the axis of the assembly building. The president’s palace (to-day’s Ganabhaban, the official residence of the Prime Minister), was one of the first structures to be built. The design of the Assembly building was completed in 1964. Construction work started immediately. The main structure was under construction at the time of the liberation war in 1971, when all work stopped. In 1974 the government of Bangladesh took the creditable decision of completing the building without any change.

Bangabandhu International Conference Centre (BICC)

Bangladesh’s only international convention center, the Bangabandhu International Conference Center (BICC) has always surpassed everyone’s expectations by bringing the highest number of interactions while conducting notable events, conferences, seminars, corporate shows, product launches and meetings.

The Conference Center provides specialized services and is known for its outstanding infrastructure and its team of experts who are always committed towards ensuring the smooth running of every event. Well equipped with the latest high-tech facilities and conveniences, the BICC also provides a splendid hall for exposition purposes of national and international significance. There is provision of parking facilities for both visitors and organizers as well as other exhibitor related services and conveniences.

The Election Commission

The Election Commission is an independent constitutional body in the exercise of its functions and subject only to the Constitution and other law. The Commission may authorize its Chairman or any of its members or any of its officers to exercise and perform all or any of its powers and functions under the law. Article 126 of the Constitution and Articles 4 and 5 of the Representation of the People Order, 1972 provide that it shall be the duty of all executive authorities to assist the Election Commission in the discharge of its functions. The Commission has the power to require any person or authority to perform such functions or render such assistance for the purpose of electron as it may direct.

Ministry of Defence (MoD)

Ministry of Defence (MoD) situated in Ganabhaban Complex, just to north-east of Ganabhaban.

Hospitals

Shahid Shohrawardi Hospital, one of the largest governmental hospitals and medical colleges of Dhaka is situated on Mirpur road.

National Institute of Cardiovascular Diseases & Hospital (NICVDH), Sher-e-Bangla Nagar, Dhaka, is also a large governmental hospital.

Educational Institutions

Sher-e-Bangla Agricultural University

Sher-e-Bangla Agricultural University is the most ancient agricultural university in Bangladesh, situated in Sher-e-Bangla Nagar. It was established as BAI on December 11, 1938 by Sher-e-Bangla A.K. Fazlul Huq, the Chief Minister of undivided Bengal. At that time the name of this institution was “The Bengal Agricultural Institute”. Later it becomes “East Pakistan Agricultural Institute” and on the emergence of Bangladesh as independent country in 1971, the name of this institute was spontaneously changed to Bangladesh agricultural Institute (BAI).

Since its inception the BAI had functioning as “faculty of Agriculture” under Dhaka University, the BAI-affiliated College till it’s up gradation to Sher-e-Bangla Agricultural University in 2001. On 22 June 2009, a bill was placed in the parliament to assign the President as chancellor replacing the Prime Minister.

Ganabhaban Govt. School

Ganabhaban Govt. School is a secondary school which is situated to the north of Ganabhaban Complex.

3.4 Roads and Transport System

Adjacent major roads of the study area are Mirpur road, Rokea sharani and Bijay sharani (partially).Crescent lake is also an important road of this area. Major roads are connected by narrower roads like front side road of International Trade Field. Adjacent major roads play important part in national connectivity. Consequently, a large number of vehicles are seen on the roads for transportation purpose. This situation leads the area to be one of the most vulnerable areas of the city in terms of noise pollution.

3.5 Residences and Quarters

The most important residence is Ganabhaban, which has been mentioned earlier. There is a considerable number of Government quarters are situated here, among them there are superior type of quarters for respectable persons, E-type quarters for high officials and other type of quarters can be mentioned.

3.6 Park

Chandrima Uddyan is one of the nicest parks of Dhaka City, which situated in the study area. The park is full of green trees; most of them are exotic type. Trees of different types have the ability to mitigate the ill effects of pollution. Relevantly it can be said that trees act as a barrier in the path of sound/noise waves and consequently reduces the ill effects. In this view point this part of the study area considered with much importance. Trees of this park are discussed separately in this report.

The whole Chandrima Uddyan is made magnificent by animating the adjacent Crescent Lake with light and fountains and development of adjacent panoramic views. It takes a different look when the mirrored and transparent floor of the hanging bridge on the lake radiates gentle radiance during nighttime.

The last end the garden has a two-storey structure constructed on the 24,000 cft area. A room for prayers is housed on the first floor while library, archive, museum and seminar hall are on the ground floor. The grave of former President Ziaur Rahman is situated at the centre of the park.

3.7 Vegetation Cover of the Study Area

There are different types of trees and plants in the study area. Exotic types of trees are dominant in number but there are also local varieties. Different types of trees of the study area are discussed below-

Polyalthia longifolia (Devdaru / var-pendula)

It is a lofty evergreen tree, native to India, commonly planted due to its effectiveness in alleviating noise pollution. It exhibits symmetrical pyramidal growth with willowy weeping pendulous branches and long narrow lanceolate leaves with undulate margins. The tree is known to grow over 30 ft in height.

One might mistake it as a tree with effectively without branches, but in fact an Ashoka allowed to grow naturally (without trimming the branches out for decorative reasons) grows into a normal large tree with plenty of shade. The two look identical in every way, trunk and leaves and bark and flowers, and it is perfectly obvious the straight ramrod versions are specially created much as the trimmed trees along lake Geneva are in another shape.

Samanea saman (Rain tree)

Rain tree (Samanea saman) is easily recognized by its characteristic umbrella-shaped canopy. When grown in the open, the tree usually reaches 15–25 m (50–80 ft) in height with a canopy diameter wider than the tree is tall. Rain tree is most important in the Pacific as a shade tree on small farms, along roads, in parks and pastures.

The wood has limited use for carved bowls in local markets; it could be developed more widely as a commercial timber, comparing favorably to black walnut. A multitude of minor uses is documented for rain tree, most of them of purely local significance, but all could be explored for wider applicability. Rain tree naturalizes freely almost everywhere it has been introduced and is considered an invasive pest in Vanuatu and Fiji.

Mesua Nagassarium (Nageswar)

It is common in wet zone at Sri Lanka up to 1500 meters. It has simple, narrow, oblong, dark green leaves 7–15 cm long, with a whitish underside; the emerging young leaves are red to yellowish pink and drooping. The flowers are 4–7.5 cm diameter, with four white petals and a center of numerous yellow stamens.

Albizia Chinensis (Chakua Koroi/ Albizia)

Albizia chinensis is an unarmed, deciduous or evergreen tree with a flat, spreading crown, up to 30(-43) m tall and trunk up to 70(-140) cm in diameter. Bark is dark gray, rather smooth, densely hooped, thin; and live bark is 5 mm thick & pinkish-red. Branchlets are slightly angular in the distal parts. Leaves are bipinnate; stipules and auriculate.

 Peltophorum pterocarpum (Radhachura / Yellow Flamboyant)

It is a deciduous tree growing to 15–25 m (rarely up to 50 m) tall, with a trunk diameter of up to 1 m. The leaves are bipinnate, 30-60 cm long, with 16-20 pinnae, each pinna with 20-40 oval leaflets 8-25 mm long and 4-10 mm broad. The flowers are yellow, 2.5-4 cm diameter, produced in large compound racemes up to 20 cm long. Peltophorum pterocarpum is widely grown in tropical regions as an ornamental tree, particularly in India, Bangladesh, Nigeria, Pakistan, and Florida and Hawaii in the United States. The wood has a wide variety of uses, and the foliage is used as a fodder crop.

Figure-6: Peltophorum pterocarpum (Radhachura / Yellow Flamboyant)

Delonix regia (Krishna chura/ Red Flamboyant)

It is a deciduous tree growing to 15–25 m (rarely up to 50 m) tall, with a trunk diameter of up to 1 m. The leaves are bipinnate, 30-60 cm long, with 16-20 pinnae, each pinna with 20-40 oval leaflets 8-25 mm long and 4-10 mm broad. The flowers are red, 2.5-4 cm diameter, produced in large compound racemes up to 20 cm long. It is widely grown in tropical regions as an ornamental tree, particularly in India, Bangladesh, Nigeria and Pakistan.

Tectona grandis (Sagon/ Teak)

A large to very large deciduous tree having height up to 35 meters; bark having brown or grey color and shallow longitudinal furrows; Leaves simple, opposite, broadly elliptical or obovate, acute or acuminate, coriaceous, possessing minute glandular dots; Flowers white, many, small, having pleasant smell, in large erect terminal branched tomentose cymose bladder like calyx; seeds usually 1-3, ovate, marble white. Sagon is a well known for its high grade timber. Wood is used for ship building, railways, piles in harbour, bridge-building, construction work, furniture and cabinet work.

Carallia brachiata (Matan/Carallia)

Tree usually grows along freshwater streams with obovate, opposite leaves to 16 x 8.5 cm, has scattered dark glands present on the lower leaf surface. Stipules 10 –15 (-25) cm long. It has flowers with 7 green to cream petals. Fruit of this tree is a berry 7-10 mm wide, orange to black, 1-seeded.

Callistemon linearis (Bottle brush)

This evergreen shrub or small tree gets its species name citrinus from the lemony smelling oil glands present in the olive green, lance-shaped leaves. Springs to summer flowers are terminal, axillary, and crimson colored. Plant in neutral to acid, moderately fertile soil in full sun. This plant is tough and makes and excellent hedge. C. linearis has narrower leaves.

Acacia auriculiformis (Acacia)

This plant is raised as an ornamental plant, as a shade tree and it is also raised on plantations for fuel-wood throughout south-east Asia, Oceana and in Sudan. Its wood is good for making paper, furniture and tools. It contains tannin useful in animal hide tanning. In India, its wood and charcoal are widely used for fuel. Gum from the tree is sold commercially, but it is said not to be as useful as gum arabic. The tree is used to make an analgesic by indigenous Australians. Extracts of Acacia auriculiformis heartwood inhibit fungi that attack wood.

Gliricidia sepium (Gliricidia)

Gliricidia sepium is a medium-sized tree and can grow to from 10 to 12 meters high. The bark is smooth and its color can range from a whitish gray to deep red-brown. It has composite leaves that can be 30 cm long. Each leaf is composed of leaflets that are about 2 to 7 cm long and 1 to 3 cm wide. The flowers are located on the end of branches that has no leaves. These flowers have a bright pink to lilac color that is tinged with white. A pale yellow spot is usually at the flower’s base. The tree’s fruit is a pod which is about 10 to 15 cm in length. It is green when unripe and becomes yellow-brown when it reaches maturity.

Casuarina littoria (Jhau)

It is an ornamental exotic plant and has been brought here from Australia. It is tall tree with narrow leaves.

Artocarpus heterophyllus (jackfruit)

The jackfruit is a species of tree in the mulberry family (Moraceae), which is native to parts of Southern and Southeast Asia. It is the national fruit of Bangladesh. It is well suited to tropical lowlands. Its fruit is the largest tree borne fruit in the world, reaching 80 pounds (36 kg) in weight and up to 36 inches (90 cm) long and 20 inches (50 cm) in diameter.

Mangifera indica (Mango)

Mangifera indica is a species of Mango in the Anacardiaceae family. It is found in the wild in Southern Asia and cultivated varieties have been introduced to other warm regions of the world. The species appears to have been domesticated about 4,000 years ago. The species was first moved around 400-500 BC from northeastern India to east Asia; next, in the 15th century to the Philippines; and then, in the 16th century to Africa and Brazil by the Portuguese. The species was described for science by Linnaeus in 1753.

Cocos nucifera (Coconut)

The coconut (Cocos nucifera) is an important member of the family Arecaceae (palm family). It is the only accepted species in the genus Cocos, and is a large palm, growing up to 30 m tall, with pinnate leaves 4–6 m long, and pinnae 60–90 cm long; old leaves break away cleanly, leaving the trunk smooth. The term coconut can refer to the entire coconut palm, the seed, or the fruit, which is not a botanical nut. The spelling cocoanut is an old-fashioned form of the word. The coconut palm is grown throughout the tropics for decoration, as well as for its many culinary and non-culinary uses; virtually every part of the coconut palm can be utilized by humans in some manner.

 Aegle marmelos (Bel tree)

The bel tree of the family Rutaceae, found wild or cultivated throughout India. The trees bear strong spines; alternate, compound leaves, each with three leaflets; and panicles of sweet-scented white flowers. The tree is valued for its fruit, which is oblong to pyriform in shape and 50–250 mm (2–10 inches) in diameter. The fruit has a gray or yellow rind and a sweet, thick, orange-colored pulp. The unripe fruit, sliced and sun dried, is traditionally used as a remedy for dysentery.

#.The tree species are determined with the cooperation of Mr. A N M Rubaiat, Asst.

Professor, Dept. of Botany, Islamic University, Mr. Mohammad Hossain Ali, Officer, Ministry

of Defence and Mr. Shahjahan Ali, Scientific Officer, SPARSO.

Chapter 4

Introduction

This section presents the overall state of noise pollution and its influences & effects over the study area. An effort has also been made here to analyze and present the role of vegetation covers as mitigating agent of noise pollution. The data of this chapter were collected from primary sources. Sound level data were collected by sound level meter to determine the state of noise pollution of the study area.

Secondly, a questionnaire survey was conducted to understand the people’s perception about noise pollution. All kinds of data are analyzed and presented in this chapter.

4.1 The State of Noise Pollution in the Study Area

Ganabhaban and adjacent region is the study area of this research, it is one of the most important parts of Dhaka City. Important residences, organizations, offices, hospitals, educational institutions, park, etc. are situated here in this area. Adjacent major roads are playing important part in national connectivity. Specially, honorable Prime Minister’s residence (Ganabhan) made this area more important.

As a result, many kinds of activities are being practiced here in this area and many people come here to participate in many types of activities like; administrative tasks, business, jobs, medical support, education, conference, trade expo, travelling etc. Consequently, a large number of vehicles are seen on the roads for transportation purpose. This situation leads the area to be one of the most vulnerable areas of the city in terms of noise pollution. State of noise pollution of the study area is discussed below from different views.

Table-3: Highest & Lowest Average Value of Noise Level in Working Day

Source: Sound Level Survey conducted by Mohammad Ahsanul Haq (in 2010).

 

Table-4: Highest & Lowest Average Value of Noise Level of Three Shifts in Working Day

Source: Sound Level Survey conducted by Mohammad Ahsanul Haq (in 2010).

4.1.1 The State of Noise Pollution in Working Days

Two pairs of isoline maps have been produced to present the noise level status of the study area in working days. The first pair of isoline maps is produced on the basis of “average highest value” of noise level of the different points of the study area in working days (Map-2 and Map 3). The second pair of isoline maps is produced on the basis of “average lowest value” of noise level of the different points of the study area in working days (Map-4 and Map 5).

Most Noisy Points\ Places According to Maps and Tables:

Sound level data were collected by a portable digital sound level meter from 9a.m. to 8 p.m. To determine the average value of the noise pollution, readings were taken repeatedly after certain interval. In this study, day time considered from 6am to 9 p.m. according to Environmental Conservation Act- 1995 and Rules-1997(Rule-12, Schedule-4).

Viewing the first pair of isoline maps based on average highest value of noise level (Map-2 and Map-3) and the second pair of isoline maps based on average lowest value of noise level (Map-4 and Map-5) along with Table-3, it can be realized that the most noisy places of the study area are (highest and lowest average values are mentioned in the bracket as acronym, hav=highest average value & lav=lowest average value).-

Bijay Sharani-Road Crossing (hav 86dB & lav 74dB), Front of PM’s Residence/Ganabhaban (hav 84.5dB & lav 71.6dB), Mirpur Road (hav 83.6dB & lav 72.3 dB), Rokea Sharani (hav 83dB & lav 71.3dB), Front side of Shohrawardi Hospital (hav 83 dB & lav 71.6dB), Front side of Bangabandhu International Conference Centre-BICC (hav 82dB & lav 68dB), Front side E.C. (hav 81dB & lav 68.6dB), Front side of NICVD (National Institute of Cardio-Vascular Diseases) Hospital (hav 79dB & lav 72.6dB), Crescent Lake Road (hav 80.6dB &lav 69dB),Front Side Road of International Trade Fair Field (hav 78.6dB & lav 64dB), and Agargaon Police Box (hav 78dB & lav 63.6dB).

These are the most important places or points of the study area. Huge numbers of people come, visits and do their activities here for various reasons and because of this frequentation a large number of motor vehicles pass through the adjacent roads. Major roads of this area are important part of national connectivity; this causes more traffic flow in addition. As a result of heavy traffic flow, these points remain noisy and the related influence zones remain vulnerable.

The influence zones of these points cover important institutions, offices, special centres, hospitals and residences. Especially Honorable PM’s residence is partially affected by the influence of most noisy points like nodal point of the front side of the Ganabhaban (hav 84.5dB & 71.6dB) and Mirpur Road (hav 83.6 dB and lav 72.3dB). This situation makes the residence vulnerable in the context of noise pollution. According to Environmental conservation Act-1995 (ECA’95) and Environmental conservation Rules 1997 (ECR’97), Standard for special establishments (up to a radius of 100 meters) is 45dB for day time (6am to 9pm), but the actual level is much higher than that of standard level.

Two large hospitals (Shohrawardi Hospital and NICVDH) are also affected by the influence of high noise level. This situation makes the patients most vulnerable and it would cause serious problems for the patients who are suffering from heart and brain diseases. According to ECA’95 and ECR’97 the standard level of sound for hospitals (up to radius of 100 meters) is 45dB. But in front of Shohrawardi Hospital the level is hav 82dB and lav 71.6 (within 100 m. radius) and in front of NICVH the level is hav 79 dB & lav 72.6dB (within 100m. radius), which are far above the standard level. Even the lowest average values (lav) are much above the standard.

Important institutions like Election Commission (EC) and Bangabandhu International Conference Centre (BICC) along with Agargaon police Box are also inside the influence of heavy noise pollution. This situation makes the institution vulnerable for the relevant persons. According to ECA’95 and ECR ’97 the standard for special institution is 45dB (day) (as considered silent zone). At these points actual levels are much higher than the standard level. As a matter of fact lowest values are even higher than the standard value.

Moderately Noisy Points/Places According to Maps and Tables

According to the same maps and table the moderately noisy areas of the study area are (highest and lowest average values are mentioned in brackets as acronym, hav=highest average value and lav=lowest average value).-

Front side of Ganabhaban Govt. School (hav 76dB & lav 63dB), Front of MOD (hav 74.6dB & 62.6dB), Eastern part of International Trade Fair Field (hav 73dB & 59dB), Middle part of International Trade Fair Field (hav 72.3dB & 58.3dB), Western part of International Trade Fair Field (hav71dB & lav 57dB), MOD Mosque (hav 71dB & lav 54dB), Govt. Quarters of Ganabhaban area (hav 70.6dB & 54dB), and Sher-e-Bangla Agriculture University (hav 68dB & 57dB).

In the moderately affected Zone, flow of motor vehicle fluctuates along with many kinds of human activities. Mainly opening and closing time of offices & institutions causes the fluctuation. Fluctuation of traffic flow is also affected by the traffic jams of the major roads because during the traffic jam, vehicles try to pass through the narrow link roads to avoid the jam. In this zone roads are narrow and zigzag type, which mainly keep the connectivity with the major roads. In this roads number of vehicles are less than major roads and they cannot be driven at higher speed. Consequently noise pollution remains at moderate level.

Two educational institutions are affected by the moderate noise pollution. They are Sher-e-Bangla Agriculture University and Ganabhaban Govt. School. Ganabhaban School is affected more by the noise pollution as it is more adjacent to a road and in addition the road is an internal turning point. So vehicles gathered here and honk horn in the time of turning.

Standard level for educational institution is 45dB at day (ECA’95 and ECR’97). But the actual level (at Ganabhaban School – hav 76dB & lav 63dB and at Sher-e-Bangla Agriculture University hav 68 dB and lav 57dB) is much higher than that of standard limit even in the moderately affected area. Lowest average values are also not satisfactory. This situation increases the vulnerability of the students and noise can disturb the attentiveness of the learning of the students.

Ministry of Defence (MoD) is also affected by the moderate noise pollution. In front of MoD highest average noise is 74.6dB and lowest average value is 62.6, where as the standard level is 60dB (for mixed zones- ECA’95 & ECR’97). Even the lowest value is higher than the standard in this place.

The standard for quarters or residential area is 50dB at day (ECA’95 & ECR’97). But the actual highest average value is 70.6dB and lowest average value is 54dB in Govt. Quarters of Ganabhaban area. So both the values are higher than the standard.

International Trade Fair Field is a field without any vegetation cover. In this place noise pollution is moderate. Actually it is affected by the noise pollution of the front side road of its.

Relatively Quiet Places According to Maps and Tables:

The same maps and table also shows that the less noisy or relatively quiet points or places are (highest and lowest average values are mentioned in the bracket as acronym, hav=highest average value & lav=lowest average value).-

Eastern part of Chandrima Uddyan (hav 60.5dB & lav 53dB), Middle part of Chandrima Uddyan (hav 58.6dB & lav 51.6dB), and Western part of Chandrima Uddyan (hav 57.5dB & lav 50.6dB).The three parts of Chandrima Uddyan remain relatively quiet. The vegetation cover act as a barrier to noise waves, so the effect of noise reduces significantly.

Time of Highest and Lowest Level of Noise in Working Days:

It is observed in the field investigation that noise level remains higher at morning (9am to 11am) and evening (5pm to 8pm). It can also be realized by viewing the Table – 4 carefully.

Noise level remains low at noon (12pm to 4pm). Noise level reaches at pick in evening (5pm to 8pm). These facts can be viewed from the Table – 4 with close attention.

Noise level increases at morning as it is the beginning of office hours. At morning huge number of people goes to office by many kinds of vehicles and noise is created by these large numbers of vehicles. At the evening & twilight hours, noise level reaches at the pick as traffic flow reaches a pick at that time. It is the closing time of offices and schools, more over a large number of people come out for marketing and other purposes in this time. For this reason a huge number of vehicles are seen on the roads for transportation purpose, which makes this time most noisy. The evening portion of the Table-4 shows the reality.

Noon time is free from the opening and closing session, so the traffic flow at this time remains relatively lower than that of morning and evening. As a result, level of noise also remains relatively lower than that of morning and evening.

Comparison between highest and lowest average values:

Map-6 shows the comparison between highest and lowest average values of the points\places of the study area in working days. This map provides a comparative idea and it will be helpful to know, how the noise levels are fluctuating in certain points. Hence, this map shows that the fluctuations of noise level are not so significant and this fact indicates that the overall level of noise pollution is not satisfactory as the lowest levels are not even very lower than the highest levels.

4.1.2 The State of Noise Pollution in Holy Days

Holidays are comparatively less noisy than the working days, as all kinds of institutions remain closed. Therefore amount of traffic also remains moderate.

Two pairs of isoline map have been produced to present the noise level status of the study area in holy days. The first pair of isoline maps is produced on the basis of “average highest value” of noise level of the different points of the study area in holy days (Map-7 and Map-8). The second pair of isoline maps is produced on the basis of “average lowest value” of noise level of the different points of the study area in holy days (Map-9 and Map-10).

These maps and Table-5 show the state of noise pollution in holy day. Here it is clear that the situation is not satisfactory in holidays too.

The places\points which are influenced by the high noise level in working days, most of them are also influenced by the high noise level in holydays too. As the major roads, adjacent to the study area play a vital role in national & local connectivity. Even in holydays the traffic flow remain moderately high in those roads. At present, many of the city dwellers and day laborers do jobs & business in holydays and they have to travel by buses and other vehicles. Many people come to this area to visit park, to attend conference or fair. Many people pass through the roads for marketing purpose. So the roads contain a considerable amount of traffic flow in holydays too.

Table-5: Highest & Lowest Average Value of Noise Level in Holy Day

Source: Sound Level Survey conducted by Mohammad Ahsanul Haq (in 2010).

Table-6: Highest & Lowest Average Value of Noise Level of Three Shifts in Holy Day

Source: Sound Level Survey conducted by Mohammad Ahsanul Haq (in 2010).

As a result of the before mentioned facts, in holydays, at Mirpur road the highest average value is 80.6dB and the lowest average value is 72dB, in front of PM’s residence (which is actually a nodal point of Mirpur road) the highest average value is 81dB and the lowest average value is 72dB, at Bijay Sharani-Road Crossing the highest average value is 81dB and the lowest average value is 71dB, at Rokea Sharani the highest average value is 81dB and the lowest average value is 68dB, at Crescent Lake Road highest average value is 77.7dB and the lowest average value is 69dB.

Many people come to this area to attend conference and meetings in BICC in holydays even. Moreover, most of the time, many types of fairs and events are organized here in this important centre. So the noise level remains high even in holydays here. In holydays, the highest average value is 79.6dB and the lowest average value is 69.5dB at BICC. This is not at all satisfactory.

Unfortunately, diseases & accidents do not follow the rules of holyday, so the serious patients have to come to the hospitals in ambulances with honking siren. Fortunate of them got released. Moreover, the hospitals are also adjacent to a major road like Mirpur road (which remains always busy). Consequently, the noise level remains serious even in holydays. The highest average value at the front of Shohrawardi Hospital is 79dB and the lowest average value is 71dB, and at the front of NICVDH the highest average value is 78.3dB and the lowest average value is 69.8dB. The levels are much more above the standard level.

The internal parts of the study area like Govt. Quarters, Sher-e-Bangla Agri. Univ., Int’l Trade Fair Field and narrow roads remain relatively less noisy in holy days. The highest average level of noise stays under 65dB in these areas in holy days.

Chandrima Uddyan remains relatively quiet in the holydays also. Here, on and average, the level of sound stays below 55dB.

Table-6 shows that, most of the cases noise level remains high at evening (5pm to 8pm). At holyday evening; many people goes out for marketing, communicating relatives & friends, amusement and other purposes. These facts cause heavy traffic flow in the road and consequently, noise. At noon, the study area remains comparatively low. People take rest in side home at noon, offices remain closed also and some people go to mosque to attend the Juma salat. For these facts, noon is comparatively moderate or less noisy.

Table-7: Average Value of Working Day & Holy Day and their Differences

Source: Sound Level Survey conducted by Mohammad Ahsanul Haq (in 2010).

Difference between average noise levels of working days and holydays can be realized by viewing the Table-7. On the major roads and points\places beside the major roads, the difference is not significant as traffic flow remains almost high in the holy days too (causes discussed earlier in the last Para of 58 page). But on the internal narrow roads and internal parts of the area (which are away from major roads), the difference is significant on the contrary. Because, these parts remain comparatively free from heavy traffic flow on holy days and as a result, noise level also remain relatively low.

Map-11 shows the comparison between highest and lowest average values of the points of the study area in holydays. This map provides a comparative idea and it will be helpful to know, how the noise levels are fluctuating in certain points in holy days.

 4.1.3 The State of Noise Pollution Considering both days Situations

(Based on the average noise level value of both days situations)

One pair of isoline map has been produced to present the noise level status of the study area considering both days’ situations. The pair of isoline maps is produced on the basis of average noise level value (considering both days’ situations) of the different points of the study area (Map-12 and Map-13).

These maps and Table-8 show the state of noise pollution of the study area considering both days situation.

According to the above mentioned maps and table, the most noisy places of the study area are (average values are mentioned in the bracket).-

Bijay Sharani-Road Crossing (78dB), Front of PM’s Residence/Ganabhaban (77.5dB), Mirpur Road (77 dB), Rokea Sharani (76dB), Front side of Shohrawardi Hospital (76dB), Front side of Bangabandhu International Conference Centre-BICC (75dB), Front side E.C. (74.5dB), Front side of NICVD Hospital (75dB), Crescent Lake Road (74dB), and Agargaon Police Box (69dB).

The causes of high noise level in this places\points have been mentioned earlier in the “4.1.1 The State of Noise Pollution in Working Days” part of this thesis.

According to the same maps and table the moderately noisy areas of the study area are (average values are mentioned in brackets).-

Front Side Road of International Trade Fair Field (67dB), Front side of Ganabhaban Govt. School (67dB), Front of MOD (67dB), Eastern part of International Trade Fair Field (62dB), Middle part of International Trade Fair Field (61dB), Western part of International Trade Fair Field (59.5dB), MOD Mosque (61.5dB), Govt. Quarters of Ganabhaban area (60dB), and Sher-e-Bangla Agriculture University (60dB).

The same maps and table also shows that the less noisy or relatively quiet points or places are (average values are mentioned in the bracket).-

Eastern part of Chandrima Uddyan (55.5dB), Middle part of Chandrima Uddyan (54dB), and Western part of Chandrima Uddyan (54dB).The three parts of Chandrima Uddyan remain relatively quiet. The vegetation cover act as a barrier to noise waves, so the effect of noise reduces significantly.

Table-8: Average Noise Level Value (Considering Both Days Situations)

Source: Sound Level Survey conducted by Mohammad Ahsanul Haq (in 2010).

 4.2 Role of Vegetation Covers in Mitigating the Noise Level

It can be realized from all the above mentioned maps and tables of this chapter-4 that vegetation covers have a significant role in mitigating the magnitude of the noise level.

The average levels of sound in the three parts of the Chandrima Uddyan are mentioned below-

At the Eastern part of Chandrima Uddyan the average value is 55.5dB, at the Middle part of Chandrima Uddyan the average value is 54dB, and at the Western part of Chandrima Uddyan the average value is 54dB.

This situation of this park can be compared with Int’l Trade Fair Field. Two places are situated side by side and divided by a brick wall. But the main visible difference is that, Chandrima Uddyan is covered with vegetation and on the other hand, Int’l Trade Fair Field is a bare field without any vegetation cover.

To compare the noise level status of these fields, noise level data has been collected from 3 points of each of the fields, keeping almost same distance from the adjacent roads (around 25 meters from the roads).

The noise level of Chandrima Uddyan is influence by three adjacent roads and they are Crescent lake road (Average noise level is 74dB), Rokeya Sharani (Average noise level is 76dB) and Bijay Sharani-road crossing (Average noise level is 78dB). The average value of these three roads is 76dB. The average noise level value of the three points inside the Chandrima Uddyan is 54.5dB. The difference between the average of noise values of the three roads (76dB) and the average of three points inside Chandrima Uddyan (54.5) is 21.5dB (76dB-54.5dB=21.5dB).

The noise level of Int’l Trade Fair Field is influenced by the adjacent front side road. The average noise level of the “Front Side Road of Int’l Trade Fair Field” is 67dB and the average noise level of the three points of the trade fair field is 60.8dB. The difference between these two average value is only 6.2dB (67dB-60.8dB=6.2dB). The distance from the adjacent road (around 25 meter) is responsible for this reduction.

Actually vegetation cover act as a barrier in the path of noise waves, it also shows a character of absorbing noise. Through the model it can be shown that the noise level is reducing by the vegetation cover. But discovering “how vegetation cover is doing such act” is another research job for botanists.

It can be concluded that plantation of trees (especially beside roads and along the boundaries of the residences) would be a very much effective way of mitigating noise.

 

A brief discussion about different species of trees of the study area is included in chapter-3.

4.3 Noise Pollution in Educational Institutions & Hospitals

Hospitals and Educational Institutions are the most vulnerable places. Because noise can cause more harm to the patients and school going children. For this reason, in Environment Conservation Act-1995 and Rules-1997 these places categorized as silent zone where the standard sound limit is 45 dB (daytime).

Educational Institutions remain open at working days. Both hospitals and educational institutions are mainly much affected by the noise pollution in five working days. So in this case, only working days situations are considered.

Viewing the first pair of isoline maps based on average highest value of noise level (Map-2 and Map-3) in working days and the second pair of isoline maps based on average lowest value of noise level (Map-4 and Map-5) in working days along with Table-3, it can be realized that the hospitals & educational institutions are much affected by the noise pollution in working days.

In the study area, noise level data were collected from the front of two large hospitals (within 100 m. radius), they are- Shohrawardi Hospital and NICVDH. Both the hospitals are affected by the influence of high noise level. This situation makes the patients most vulnerable and it would cause serious problems for the patients who are suffering from heart and brain diseases. According to ECA’95 and ECR’97 the standard level of sound for hospitals (up to radius of 100 meters) is 45dB. But in front of Shohrawardi Hospital the highest average value is 82dB and the lowest average value is 71.6dB (within 100 m. radius) and in front of NICVH the highest average value is 79 dB & the lowest average value is 72.6dB (within 100m. radius), which are far above the standard level. Even the lowest average values are much above the standard.

Two educational institutions are affected by the moderate noise pollution. They are Sher-e-Bangla Agriculture University and Ganabhaban Govt. School. Ganabhaban School is affected more by the noise pollution as it is more adjacent to a road and in addition the road is an internal turning point. So vehicles gathered here and honk horn in the time of turning. Standard level for educational institution is 45dB at day (ECA’95 and ECR’97). But the actual situation is much serious.

At Ganabhaban School – the highest average value is 76dB & the lowest average value is 63dB and at Sher-e-Bangla Agriculture University the highest average value is 68 dB and the lowest average value is 57dB, in both the cases the actual levels are much higher than that of standard limit. Lowest average values are also not satisfactory. This situation increases the vulnerability of the students and noise can disturb the attentiveness of the learning of the students.

Diagram-2: Noise Pollution in Hospitals & Educational Institutions (in working day)

Table-9: Standards of Sound*

Note:

1. The time from 6 am. To 9pm is counted as daytime.
2. The time from 9 pm to 6 am is counted as night time.
3. Area up to a radius of 100 meters around hospitals or educational institutions or special institutions/establishments identified/to be identified by the Government is designated as Silent Zones where use of horns of vehicles or other audio signals, and loudspeakers are prohibited.

*According to Environmental conservation Act-1995 (ECA’95) and Environmental conservation Rules 1997 (ECR’97),-Rule 12, Schedule-4. 

Chapter 5

 5.1 Findings of the study

This thesis has been produced mainly on the basis of primary data source and the investigations carried out right on the spot. No research work titled as “Noise Pollution Modelling in Dhaka City: A GIS Approach” has been done before and no such type of investigation has been occurred at Ganabhaban & adjacent area prior to this effort. The following findings, therefore, should serve as the first hand knowledge about the status and vulnerability of noise pollution, particularly for the study area in Dhaka city.

Completion of the “Noise Pollution Modelling” of the study area has made it possible to explore the under mentioned findings-

۞ Noise Pollution is severe in Ganabhaban and adjacent area; average sound level is  very high. Especially in those places which are adjacent to major roads. The highest average noise level recorded at a nodal point is 86 dB (at Bijay Sharani-Road Crossing in working days).

۞ Noise level remains higher at morning  (9am to 11am) and evening  (5pm to 8pm).

۞Noise level reaches at pick in evening (5pm to 8pm).

۞ Noise level remains lower from 12 pm to 4 pm at noon.

۞ Places and their influence zones are demarcated as well as the quantity of vulnerable institutions in the different influence zones of noise pollution of the study area are determined. Relatively quiet places are also demarcated by the same manner.

۞ The vegetation covers can significantly mitigate the effect of noise pollution. So plantation can be utilized as a remedy to reduce the problem of noise.

۞ Most badly affected classes of professionals due to noise pollution are; traffic police, drivers, roadside shopkeepers and businessmen for their prolonged expose to the   intensive noise.

5.2 Remedial Measures & Recommendations

Noise or “Unwanted sound” is a common form of atmospheric pollution in the modern cities of to-day including in the city of Dhaka, the Capital of Bangladesh. Noise causes several undesirable effects, which include damage to hearing, loss of sleeping, feeling of fatigue etc. All these may reduce human efficiency at this present day of economic crisis. As such this alarming problem of today detrimental to our normal existence in this good earth – the home of man, deserves highest attention in quest of proper and effective solutions or remedial measures.

The tiresome, painstaking research work has been accomplished with utmost sincerity and care for achieving this purpose. After a careful study of the problem through direct investigation, observation, books, journals, seminar papers, magazines, dailies and weeklies; the following remedies may be adopted-

Control of Noise by Plantation of Trees

According to the results of this research, it can be predicted that vegetation covers can reduce more or less 15dB noise. Actually vegetation cover act as a barrier in the path of noise waves, it also shows a character of absorbing noise. So it can be recommended that plantation of trees especially beside roads and along the boundary walls of residences would be a very much effective way of mitigating noise.

Control of Traffic Noise

Roadway noise is the most widespread environmental component of noise pollution worldwide. There are a variety of effective strategies for mitigating adverse sound levels including:

• Use of noise barriers
• Limitation of vehicle speeds
• Alteration of roadway surface texture
• Limitation of heavy duty vehicles
• Use of traffic controls that smooth vehicle flow to reduce braking and
  acceleration
• Innovative tire design and other methods
• Noise level specification must be adopted into new designing of both machinery and transport system.
• Improved machine for sound protection should be adopted.

Control of Noise by 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 of Aircraft noise

Aircraft noise can be reduced to some extent by

• Designing of quieter jet engines, which activity was pursued vigorously in the 1970s and 80s. This strategy has had limited but noticeable improvement on urban sound levels.
• Operational controls, such as altering flight paths and time of day runway use have    demonstrated significant benefits for residential populations near airport

Industrial noise for worker exposure can be reduced to some extent if the under mentioned points are considered carefully

• Sound created practice has emphasized redesign of industrial equipment.
• Shock mounting assemblies and physical barriers in the workplace can reduce noise.

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 minimization 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. 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.

Control over vibrations: The vibrations of materials may be controlled using proper foundations, rubber padding etc. to reduce the noise levels caused by vibrations

Reducing the noise levels from domestic sectors

To control noise in a private place especially within a single room is however easy to control. As much as 95% of the sound may be soaked up in rugs, draperies and special acoustical tiles that absorb sound and convert it to heat. To cope with such situation, western architecture has in corporate measure to reduce noise levels below the maximal permissible. In Bangladesh anti-noise measures at the domestic level are a myth.

The interior decorators of today may take proper acoustical planning and the liberal use of heavy draperies, carpeting and sound absorbing tiles. Personal protection devices such as car plugs and muffs play a major role in protecting the individual and their use may be made of compulsory in the areas where required. The domestic noise coming from radio, tape recorders, television sets, mixers, washing machines, cooking operations can be minimized by their selective and judicious operation. Speaking at low voices enough for communication reduces the excess noise levels.

Control of Noise by Growing Awareness

A change of outlook towards noise pollution is very much required for the control of noise
pollution. The drivers, Traffic polices and all other citizens must be made aware of his role in eliminating noise from roads, and other sources of origin.

Only our combined contribution can help to make our daily lives a more quiet and pleasant one.

Control of Noise by Legislative Measures

At the national level, proper legislation and its strict enforcement should be ensured. Exemplary penalty should be introduced for any kind of violation. Import of hydraulic horns should be prohibited and penalty of use should be made considerably harder.

Prohibition on usage of loud speakers: The usage of loudspeakers in the habitant zones except for important meetings / functions should be prohibited. Now-a-days, the urban administration of the metro cities in India is becoming stringent on usage of loudspeakers.

1. Individual protection for noise pollution
2. Wearing earplugs in noisy places can protect an individual.
3. Conversation and rest areas in the home should be kept away from the sources of noise (Open windows and doors).
4. Home should be Sound-treated: Usage of heavy curtains on the windows, acoustical tile on the ceiling and walls, rugs on the floors is required and caulking and sealing of all air leaks can reduce the noise coming in from outside.
5. The volume of stereos should be turned down, especially those with headsets.
6. Stereos, radios, and televisions should be turned down.
7. Pets should be kept quiet.
8. Horns should not be honked except in an emergency.
9. Auto and truck engines, air conditioners, and appliances should be kept in good repair.
10. Purchasing of the least noisy air conditioner or vacuum cleaner is needed.
11. A demand for quieter appliances should be created.
12. Neighbor’s right to quiet should be respected.

5.3 Research Problems

Following problems are found during the research study;

1. Necessary instruments like sound level meters are very costly and not easily obtainable here in Bangladesh.
2. Noise pollution level is not at all static all the time; it is rather fluctuating from time to time. So prolonged and careful observation is very much required for accurate data acquisition. Short time observation may be misleading. Comparative study of the different aspects of problem may not be possible in short time observation.
3. Noise level data collection is money and time consuming.
4. Sometime bad weather causes much problem in noise level data collection process.

5.4 Conclusion.

The noise pollution is a major health hazard of today in urban areas of Bangladesh. It is undoubtedly highest in the capital city – Dhaka, of which Ganabhaban and adjacent area, the research area is essentially one of the most important affected areas.

When policy makers, administrators of different countries have made tremendous progress in controlling pollution within the tolerable limits, at the same time in Bangladesh instead of combating the noise pollution, millions of people are left exposed to noise. As a result, fatal diseases from deafness to heart attack due to uncontrolled noise pollution are occurring.

A significant change of outlook of the administrators, legislators, elite’s of the society, high officials etc. towards noise pollution are very much essential for the proper control of noise pollution.

The role of government is very important towards the control of noise pollution. The Government may take measure like import of required machineries for sound control, research materials, and silencers.

The government may take initiative in making proper legislations and regulating measures for this purpose. At present, there is very little propaganda against noise pollution. Commoners are not aware of the severe consequences of noise pollution. Electronic and print media can make an effort to aware the people about the problem. Plants and vegetation covers help significantly to control the noise; it should be adopted widely here in Bangladesh.

Noise level specification must be entered into designing of both machinery and transport system by the government planners. N.G.O. and other concerned institutions.

In short, everybody should take part in controlling this problem. Our combined
contribution can help to make our daily lives a more quiet, peaceful and pleasant in this earth-the happy home of mankind.