Noise pollution:
Any
undesirable sound that makes the living creature to feel discomfort is said to
be noise pollution. Normally sound does not become noise unless and until it
exceeds the threshold level of hearing. It depends upon one’s perception.
Noise emitted from all sources except noise at industrial work place is referred to as environmental noise or community noise or residential noise or domestic noise, whereas noise emitted at industrial work places is termed as occupational noise or industrial noise.
Measurement
Sound pressure is measured in logarithmic units called decibels (dB) with the help of
an instrument known as Sound Level Meter.
The
maximum threshold for humans is 80 dB.
Some definitions by different
authors:
According
to Ogunsote (1991,2010) noise pollution is defined as an unwanted or damaging
sound which interfere with people are trying to do, or that which has an
adverse effect on health and safety.
Ephraime
(2002) defined noise pollution as undesirable sound and erratic, intermittent
or statically random oscillation.
Noise
according to Microsoft Encarta (2007) is the exposure of people or animals to
levels of sounds that are annoying, stressful or damaging to the ears.
As
far as sound is concerned it is comprised of wave motion in air or any other medium,
sound travel through these mediums from the source to the recipients. the rate
of oscillations of the medium is referred as frequency of the sound. According
to WHO sound levels less than 70 dB are not damaging regardless of exposure duration.
Noise level beyond 85 dB with an exposure time of more than 8 hours is
detrimental.
Noise pollution level and its harmful
effects:
Level
in dB |
Effects |
Up to 23 |
No disturbance |
30-60 |
Stress, tension, psychological illnesses
heart attack |
60-90 |
Damage to health, disturbance in stomach
gall function, pain in muscles, disturbance in sleeping |
60-120 |
Damage to health and ontological (ear diseases) |
Above 120 |
Painful effects in long run |
Level
in dB |
Activities |
10 |
Breathing, grand canyon at night,
no birds no wind |
20 |
Quiet room, light wind in trees |
30 |
Rustling of leaves, soft music,
whisper |
40 |
Average home noise |
45 |
Refrigerator, forced air heating
systems |
50 |
Moderate rain, washing machine |
60 |
General conservation, computer
rooms |
70 |
Busy street, vacuum cleaner |
85 |
City traffic, lathe machine, lawn
movers, alarm clock |
95 |
Motorbike, riveting |
100 |
Chainsaw |
105 |
MP3 player at max volume, air
compressors |
120 |
Sirens, sports crowd, rock concert,
air plane take off |
130 |
Pneumatic tools, jack hammers |
150 |
Firecrackers |
According
to Ougnsote (1991) the major sources of noise pollution can be broadly
categorized into two external and internal sources. However, Gregory (1998)
identified three categories of noise as
Sources
associated with activities and office equipment
Sources
associated with operation of building services
Sources
of environmental sound from outside the building.
Ganiyu
and Ogunsote in (2010) categorized first two categories of Gregor
classification as internal and third one as external source
External Sources
These
include a variety of sources such as
Transportation
The
U. S. Environmental Protection Agency (USEPA) has identified transportation as
one of the most prevalent external source of noise pollution around the globe.
The increased number of automobiles resulted in increased noise pollution. They
include heavy trucks, bulldozers, buses, cars etc., Their speed and exhaust
system determine their noise. the stigma of indiscriminate use of horns is also
attached with this source
Industries
As
we know that in the present scenario there is no any work in the industries
that is carried out without the involvement of machines. They not only use a
single machine but a combination of machines their working produce enormous
noise almost every industry produce noise some of the major noise producing industries
include textile mills, steel manufacturing industries.
Construction
Use
of heaver machinery for construction and demolition purpose of roads, bridges
dams etc. accounts for the noise pollution to a great extent.
Mining operations
Here
in this case heavy machinery is also used for drilling the mines for extraction
of various minerals while performing this activity a considerable amount of
noise is generated.
Public
announcements
Use
of loud speakers to address the public on various occasions for different
purposes contribute to noise pollution. These include political rallies, street
hawkers.
Agricultural
machinery
In
this modern era the use of use of heavy machinery dominated the agricultural
activities these include tractors, water pumps, generators etc. they produce a
lot of noise and pollute the environment.
Military
equipment
Military use a number of artillery equipment such as bullets, grenades, mortar shells, rickets missiles jets etc. on explosion these contribute to noise pollution.
Thundering
This
is a natural phenomenon it produces a loud sound which become noise.
Fire crackers
The
use of fire crackers especially by children on various religious occasions add
an enormous sound in the environment.
Internal Sources
Include
noise from household and office activities.
Household
activities
A number of activities carried out in houses add noise in the environment these activities include loud conversation, high volume of audio video gadgets, door bells alarm clocks pressure cookers construction, electrical appliances such as refrigerators, coolers, fans washing machines, grinders etc. contribute to household noise.
Office
activities
A
large number of mechanical setup in the offices become source of noise
pollution. The office equipment includes printers, typewriters, door bells, loud
conversation ventilation system and many more.
According
to USEPA there are direct links between noise and health, also noise pollution
adversely affect the lives of millions of people.
Effect
depend on exposure to noise and level of noise produced. sudden noise
generation is more fetal as it may lead to heart or brain stroke.
Effects
on human health
Noise
pollution effect the health of humans to a great extent these include
Hearing
impairment
Continuous
exposure to noise leads to hearing impairments such as permanent or temporary deafness,
tinnitus (ringing in the ears) etc. these ailments usually occurs in those who
works in industries and other construction activities where exposure to noise
is quite long. According to WHO 10% of the global population is currently
exposed to noise level that could lead to hearing impairments.
Sleep
disturbance
Noise
is quite common factor for sleep disturbance in this case the peace of mind is
distracted. According to Hobson (1989) sleep disturbance effects include
difficulty in falling asleep, awakening, alteration of sleep stages or depth
and reduction in rapid eye movement REM. Berglund and Lindvall add more effects
as increased blood pressure and increased heart rate. For a good sleep it is
believed that indoor sound pressure levels should not exceed approximately 45
Db LA max more than 10-15 times per night (Vallet and Vernet 1991).
Cardiovascular
and physiological effects
Noise
pollution may lead to cardiovascular effects due to release of stress hormones
such as adrenaline and cortisol if the exposure continues to LAeq,24h values in
the range of 65-70 dB or more it will lead to high blood pressure, heart
diseases and strokes.
Mental
health effects
Noise
pollution effect the mental health of humans to a great extent the various
symptoms during this complication include anxiety, emotional stress, nervous
complaints, headache, nausea, sexual impotency, change in mood, social
conflicts neurosis and psychosis. According
to Stansfeld (1992) exposure to high levels of occupational noise has been
associated with the development of neurosis and irritability and exposure to
high level environmental noise deteriorate mental health.
Effect
on performance
Exposure
to noise effect the performance of all age group especially children learning
and cognitive development is hampered to a great extent.
Emotion
and behavioral changes
Prolonged
exposure to noise may lead to annoyance and anger.
Birth
Effects
Ephraime (2002) believe that that noise pollution in cities poses greatest threat to unborn babies and children.
Interference with Immune System
WHO
says that prolonged exposure to sound above 80 dB can interfere with immune
system.
Effect
on Wild and Marine Animals
Reduction in feeding
pattern of birds and animal’s
Under noisy environment birds and animals feeding pattern
is effected because the feel unsecure, which result in change in foraging,
vocal communication and flushing responses.
Many marine animals especially whales and dolphins
find it difficult to locate their food and fail to communicate and defend themselves
in noisy environment created by submarines because whales and dolphins locate
their food, communicate and defend with the help of their sense of hearing in
this way they swim towards the shore during this they got injuries or die.
Unnecessary migration
Continuous noise in certain habitats due to various
activities such as construction of roads, mining operations etc. force local
avian and faunal species to migrate to quitter habitats where they fail to cope
up and finally die off.
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