Noise Pollution:
Noise is unwanted, unpleasant & annoying sound. Even music or speech disproportionately amplified at a close distance from listeners produces a painful effect. Being unwanted
something soothing and melodious music dose not produce the desirable effect on busy examinees or tired patients. Thus the noise is usually judged from the aspects of desirability and loudness.
Encyclopedia Americana defines it as, “unwanted sound which is pleasant to some ears, may be extremely unpleasant to others, depending on a no. of psychological factors.”
Steady noise: is a noise with negligible small fluctuations of level within the period of observation.
Non-steady noise: is a noise whose level shifts significantly during the period of observation.
Intermittent noise: is a noise whose level suddenly drops to the level of background noise several times during the period of observation.
small shopkeepers etc. Some regulation regarding use of horns, particularly banning hydraulic horns and raising public awareness against the habit of honking can help in solving this situation to a large extent.
Causes of noise pollution:
One form of pollution that is characteristic of industrial societies is noise. The intensity of sound is measured in logarithmic units known as decibels (db); a change from a level of 10 decibels to one of 20 decibels actually represents a 100-fold increase in the sound level. At a level of 80 decibels, sound is annoying; but steady exposure to noise in excess of 90 decibels—a level that is frequently exceeded by many common urban sounds, such as jackhammers, jet planes, and excessively loud music—can cause permanent loss of hearing. In addition to causing loss of hearing, there is some evidence that noise can produce other deleterious effects on human health and on work performance.
A study was recently
conducted in the cities of Dhaka, Chittagong and Khulna by the Department of
Environment (DoE), sponsored by the World Health Organization, to measure the
extent of sound pollution, types of noise, sources of noise and exposure to
noise. Some 45 localities in Dhaka city were surveyed using the sound level
meter, which covered 18 generic sensitive areas that comprise silent areas
like educational institutions, hospital, mosques, and temples. Out of 45 the
areas 29 showed noise level above the permissible limits accepted by DoE. The
remaining 16 areas showed noise level fluctuating in and around the
permissible limits accepted by DoE. In
Chittagong,
out of the 45 areas 28 showed noise level above the permissible limits
accepted by DoE. The remaining 17 areas showed noise level fluctuating in and
around the permissible limits accepted by DoE. In Khulna, some 34 areas were
surveyed, of which 18 showed noise level exceeding the permissible limit.
Noise
pollution in Dhaka:
Out of 45 areas surveyed in
Dhaka city, 29 showed noise level above the permissible limits accepted by DoE.
According to the severity of the noise pollution, they are classified as sever
red-zone, a moderate red-zone, and mild red-zone. The remaining 16 showed
noise level fluctuating in and around the permissible limits accepted by DoE.
(Bangladesh State of Environment Report 2000)
The level of noise
pollution in 10 representative areas in Dhaka city has been specified as
follows:
|
|
|
| Level of |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Source: (Bangladesh State of
Environment Report 2000)
Table: Measured
Noise Levels in Some Sensitive Areas of Dhaka
|
| |
| ||
| ||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
Source: GOB 1999: GOB 1997 Bangladesh Compendium of Environment Statistics
Accepted noise limits (in decibels) and current noise situation in Dhaka
Table. Noise Quality Standards, by Zone and Time of Day
|
| |
|
| |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Source: Unnayan Shamannay,
People’s Report on Bangladesh Environment 2001
For every 10 dB increase in
sound level, the apparent loudness of sound doubles. So the loudness is 2-3
times more than the government approved accepted level. Just imagine the noise
condition in Dhaka!
Noise
pollution in Chittagong city:
45 locations covering silent,
residential, commercial, industrial and mixed areas in Ctg. city were surveyed
to determine the noise level limit. Out of the 45 areas, 28 showed noise level
exceeding permissible limits and 17 showed noise level fluctuating in and around
the permissible level (Bangladesh State of Environment Report 2000).
Noise
pollution in Khulna
City:
18 out of 34 areas surveyed
in Khulna city showed noise level exceeding the permissible
limit. The highest observed decibel in
Khulna city was found to be 95.6 dB in Shiromoni BSCIC
Industrial Area where the permissible noise limit is 75.6 dB. The findings
revealed the existing noise pollution in
Khulna city. (Bangladesh
State of Environment Report 2000)
Sources of
Noise Pollution:
The incidence of noise
pollution in Bangladesh is becoming a problem of far-reaching consequences. In
the absence of a traffic rule curbing the use of horns, the noise problem has
become acute in many parts of the cities and towns. Motor cars, trucks, buses,
mini buses, aero-planes, motor cycles, trains, construction works and noises
from industrial plants are sources of noise pollution.
1. Industrial Sources:
Industries produces giant noise from vibration, reciprocation, movements,
friction, turbulence of air and gas. Responsible industries are jute mills,
power houses, cement factories, fertilizer factories, Saw mills, pulp and paper
mills, sugar factories etc.
2. Loud speakers:
Loud speakers are used on
many occasions continuously for hours together with their loudest capacity. Now
a day’s kawalis, musical nights, political meetings, mikings, religious
functions, jatra etc. are held and use loud speakers have become indispensable.
3. Auto-mobiles:
Auto mobiles contribute
towards noise pollution because no regulation is observed in blowing of horns
and use of defective silencer pipes. Traffic noise may rise from engine and
transmission, exhaust noise and break squeal, horns, hard sound due to hand
break, continuous flow vehicles with sound intensity of 77-80 dB.
The high-pitched, shrilly sound composed of all sorts horns flowing from the all
sorts of vehicles, compounded with the shouts from the bus-helpers to attract
passengers, don't seem to have any affect on his concentration.
4. Train:
The steam engine used by railway which produces a lot of noise.
5. Aircrafts:
The higher the speed of an
aircraft the greater is the noise pollution. The noise of planes can break
window panes, crack plaster and shake buildings.
6. Construction works:
Civil engineering works like road construction, drillers, stone crusher,
concrete mixing machine, tractor etc. create noise pollution of 75-93 dB.
7. Radio & microphone:
These can cause noise pollution if they are switched on with high volume.
8. Instruments:
Equipments like vacuum cleaner, grinder, electric knife, mixer, siren, mike,
musical instruments, rock music etc. make serious sound pollution.
9. Bomb blast:
There is caused by bombing in war by aircrafts or by terrorist, military
activities, nuclear tests etc. make harmful noise.
10. Indoor activities:
Indoor activities like bathing, washing, accidental breaking of glass, calling
bells, TV, air conditioner, door closing, toilet flash etc. make noise.
11. Government role:
Another problem why noise pollution has grown
unabated over the years is the absolute absence of legal intervention by the
concerned government authority. Recently the government is working on a detail
policy concerning noise pollution, informs Huq. "We, on the part of BAPA,
organized a round table discussion where experts, environment activists,
representative of civil society, media people, spoke on the issue. Our aim was
to accumulate the suggestions and hand over the resolution to the government in
the hope that they would incorporate some of them and makes the environment
policy all-embracing."
Impacts of
noise pollution:
According to the experts, if
child below three years of age hears 100 db of sound of horns from a close
range, he might lose his auditory power. It is not only hydraulic horn that does
harm to the children, the other deterrents on the way to child health are the
high sound of ratio, television, cassette players, microphones, vehicles, sound
of mills and factories and any other loud noise. When the sound cross the normal
audible limits, it becomes polluted as every human being has a normal capacity
to tolerate certain level of sound. According to the survey of the Department of
Environment, sound causes mental and physical illness among people. It causes
heart-beat, headache, indigestion, peptic ulcer and also affects sound sleep.
Anyone may become deaf for the time being if 100 db or more sound pollution
occurs for half an hour or more in any place. Working in an atmospheric of loud
sound for a long period can cause complete deafness to any person. Any sort of
sound pollution seriously affects the expecting mothers. It has been observed
that pregnant mother living near big airports give birth to more crippled,
deformed and immature children than those living in other place. According to
research report, high noise levels can seriously affect the foetus in a woman’s
womb. Congenial defects can be caused in an unborn child by intense and
sustained noise.
According to the WHO
generally 60 dB of sound can make a man deaf temporarily and 100 dB of sound can
cause complete deafness. According to the DOE sound causes mental and physical
illness among people. The effects of noise pollution can mentioned like that---
Deafness can be caused due to continuous noise exposure. Temporary deafness
occurs at 4000-6000 Hz. Cells of the inner ear are damaged and hearing
deteriorates each time we are exposed to prolonged intense sound. The most
horrible thing in noise-induced hearing loss is that it is permanent and
incurable.
Immediate or not, noise pollution has grave effects both on our physical and
mental health. "Continued exposure to noise damages one's hearing. The louder
the noise the less time it takes to cause loss of hearing. Permanent loss of
hearing occurs at 100 dB.
The
effect of noise pollution is proportionate to the duration of exposure to noise
pollution. One burst of noise, as from a passing truck, may alter endocrine, and
effect neurological and cardiovascular functions in many individuals. Prolonged
or frequent exposure to noise tends to make the physiological disturbances
chronic. Besides, noise-induced stress creates severe tension and contributes to
mental illness.
Interference with speech communication
Annoyance
Loss
in working efficiency
Visual disturbance, Low Blood circulation and Heart beat
Insomnia, Neurosis and Anxiety
Hypertension, Headache, Peptic ulcer
Behavioral and emotional stress
Undesirable change in respiration
Children are the most vulnerable to noise pollution. In
Dhaka streets with the noise
level twice and even thrice the tolerable level is extremely harmful for the
children. Besides, the loud music children listen to on stereos, sometimes
through earphones or while watching television, or at concerts where the volume
is usually extremely loud, impair hearing and harm their ability to concentrate.
We often hear on the news
about the severe air pollution in Dhaka or about insufficient supply of potable
water across the country or about the devastating arsenic contamination of
Bangladesh's groundwater; but rarely do we hear the news of noise pollution.
Here the summery of noise pollution effect are listed---
¨
97%
of students reported that their studying is disrupted by horns.
¨
86%
of the general population considers noise pollution a big problem; only
1% said it is not a problem.
¨
Among
the general population, 78% experience aggravation, 71% experience headaches,
49% bad temper, 43% difficulty concentration and trouble sleeping, and 33%
experience hearing problems from noise pollution.
¨
45%
of drivers say they honk in traffic jams.
¨
The
general public strongly supports actions to reduce noise pollution, with the
vast majority supporting improved traffic control, banning industrial activity
and brick breaking machines in urban areas, placing limits on the decibels
allowed in different areas, and banning miking for processions, advertising, and
election campaigns.
Table: Noise-induced hearing
loss (NIHL) in different industries (%)
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Source: Kameswaran (1980)
Directives for noise pollution:
A question arises
in the mind that is this major concern for the development of the society
especially in Bangladesh?
Yes. This is a
major concern for the development of the society in Bangladesh. Because noise is
a health hazard. It induces a lot of problem in the society such as noise
causes temporary or permanent deafness,
annoyance, loss in working
efficiency, visual disturbance, low blood circulation and heart beat, insomnia,
neurosis and anxiety, hypertension, headache, peptic ulcer, behavioral and
emotional stress, undesirable change in respiration,
irritating mind, that is overall mental and ultimate physical disorder.
Children are the most vulnerable to noise pollution.
Sometimes pregnant women living near a high noise producing source give birth
disabled children who are certainly a burden for the poorer society like
Bangladesh. Thus it creates disturbance in working condition that reduces the
workability of the people. As workability of people is decreased the production
is thus declined and development is hampered. So noise is a major concern for
development of the society.
One reason why
noise pollution has never come to the forefront is perhaps, "the effect of air
pollution or polythene bag is more immediate and visible than that of noise
pollution," believes Dr. Nasser Ejazul Huq, a professor of Geology at
Jahangirnagar University, who is also associated with Bangladesh Paribesh
Andolon (BAPA). To
control the noise source, several measures can be implemented which include
proper maintenance of vehicles, limited use of horns, mikes and loud speakers.
Plantation of trees and construction of sound barriers can control the noise
path (by reflecting and defusing noise).
To face the aggravating of
the state of noise pollution it is necessary to raise awareness among the public
to curb it. The following steps can be taken for noise control:
Ø
Implementation of regulations prohibiting use of hydraulic horns, as well as
stopping import and marketing of hydraulic horns used by motor vehicles.
Ø
Development of multidisciplinary hearing conservation programmer involving
industrial hygienists, engineers, nurses, audio-metric technicians, audiologists
etc.
Ø
Reduction of noise level in the workplace by adopting engineering control
methods which include regulation of spacing between source of noise and
receiver.
Ø
Sitting up of new houses, schools, college and hospitals away from noise areas.
Ø
Sitting up of traffic police anti noise brigade by government.
Ø
Conduct social survey concerning feeling of public as regards traffic noise and
involvement of the media to support noise abatement campaign.
Ø
Locating highways away from populated areas and use of bypasses and
circumferential routs.
Ø
Introduction of underground transportation system to reduce the level of noise
by reducing the existing surface transport system.
But, in Bangladesh, little
has been done so far to reduce noise pollution. The authority concerned must
create awareness among the people so that in the long run people can eradicate
noise pollution from the country once for all. [Sifatul Quader Chowdhury]
Conclusion:
Bangladesh is vulnerable to
consequences of noise pollution. She has to take measures against such
vulnerabilities to protect the gains of the process of economic development as
well as the poor who will be affected most adversely. The Government and the
people therefore needs to be vigilant and continuously participate in global and
regional environmental dialogues and negotiations and try to ensure the
environmental safety (tolerable limit of db of sound) of the country.
Reference:
BBS (1997a)
Bangladesh
Compendium of Environmental Statistics,
Bangladesh Bureau
of Statistics, Dhaka
Bangladesh.
BBS (1997b)
Statistical Yearbook of
Bangladesh,Bangladesh
Bureau of Statistics, Ministry of Planning,
Dhaka,
Bangladesh.
Chowdhury, K.I.
(2000) State of
Environment
Report, Bangladesh,2000,
Forum of
Environmental Journalist of Bangladesh (FEJB), Dhaka, Bangladesh.
DoE (1999)
National Action Plan for
Bangladesh on
Control and Prevention of Air Pollution and its Likely Transboundary Effects,
Baseline Studies, Department of Environment and Ministry of Environment
and Forest. DoE (2000) Personal Communication.
Unnayan
Shamannay, People’s Report on
Bangladesh Environment 2001,
Volume II, Database
(The University Press Limited, Dhaka, 2001).
.
.
.
