Noise pollution refers to the production of unwanted, annoying or damaging sounds. Common sources include street traffic, construction, airplanes, and consumer products. The normal level of tolerance is 80dbA, with sounds above or below this level considered noise pollution. Exposure to excessive noise can damage hair cells in the ear and lead to hearing loss over time. Noise pollution also negatively impacts humans, vegetation, animals and property. Control methods include reducing noise at the source, blocking transmission paths, and using protective equipment. Legislation regulates noise limits for different zones.

1. What is noise pollution?
production of
unwanted
sounds that
are annoying,
distracting or
damaging to
one’s
hearing.

2. Sources of noise pollution
• Street traffic
• Rail
• Airplanes &
Rockets
• Constructions
• Consumer
products

3. Level of tolerance
• Normal level of tolerance is 80dbA.
• Sound level below and above this is
considered to be as noise pollution.

4. Effects of noise pollution
• There are about 25000 hair cells in our
ear which create wave in our ear,
responding to different levels of
frequencies.
• With increasing levels of sound the cells
get destroyed decreasing our ability to
hear the high frequency sound.

5. 5
(1) It decreases the efficiency of a man
2) Lack of concentration
3) Fatigue
4) Health issues ( BP, Abortion etc)
Impact of noise on humans

6. 6
Impact of Noise on
Vegetation
• It is well known to all that plants are similar to
human being.
• They are also as sensitive as man.
• There should be cool & peaceful environment
for their better growth.
• Noise pollution causes poor quality of crops.

7. 7
Impact of Noise on
Animals
• Noise pollution damage the nervous system
of animals.
• Animal looses the balance of its mind.
• It impacts breeding

8. 8
Impact of Noise on
Property
• Loud noise is very dangerous to building,
bridges and monuments.
• It creates waves which struck the walls and
put the building in danger condition.
• It weakens the edifice of buildings.

9. Be cautious from today
• Irreversible hearing loss.
• Blood pressure rise of 5 to 10 mmHg on 8 hrs of exposure to even
70 db of sound level.
• Hearing loss begins at 80- 90 dbA. 140 dbA is painful and 180 dbA
can even kill a person.
• Amplified rock music is 120 dbA.
• Most of the vehicles are above 80 dbA level.
• High noise levels may interfere with the natural cycles of animals,
mammals including feeding behavior, breeding rituals and migration
paths.

10. Symptoms of occupational hearing loss
• Feeling of fullness in the ear.
• Sounds may seem muffled.
• Cannot hear high frequency sounds.
• Ringing in the ears while listening to the high frequency sounds.
• Loud noise for a long period of time, or sudden burst of sound can
cause occupational hearing loss.
• Hearing that does not return after an acute noise injury is
called a permanent threshold shift.

11. Legistation
• Noise Regulation Rules under the Environment
(Protection) Act of 1986.
• Features
• Industrial- 75db
• Commercial- 65 db
• Residential zones- 55 db
• Zones of silence
• No public address system after 10:00 pm and before
06:00 am.

12. 12
Control of Noise Pollution
The techniques employed for noise control can
be broadly classified as
(1) Control at source
(2) Control in the transmission path
(3) Using protective equipment.

13. 13
(1)Noise Control at Source
The noise pollution can be controlled at the source of
generation itself by employing following techniques.
(a) Reducing the noise levels from domestic sectors
(b) Maintenance of automobiles
(d) Low voice speaking
(c) Control over vibrations
(e) Prohibition on usage of loud speakers
(f) Selection of machinery
(g) Maintenance of machines

14. 14
(a) Reducing the noise levels
from domestic sectors
• The domestic noise coming from radio,
tape recorders, television sets, mixers,
washing machines, cooking operations can
be minimized by their selective and
judicious operation.

15. 15
(b) 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.

16. 16
(c) Control over vibrations
• The vibrations of materials may be controlled
using proper foundations, rubber padding
etc., to reduce the noise levels caused by
vibrations.

17. 17
(f) Selection of machinery
• Optimum selection of machinery tools or
equipment reduces excess noise levels.
• For example selection of equipment which
generate less noise due to its superior
technology etc. is also an important factor in
noise minimization strategy.

18. PH 0101 UNIT 1 LECTURE 9 18
(g) 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 become loose while
on a rugged path of journey which generate
noise and cause annoyance to the
driver/passenger.

19. PH 0101 UNIT 1 LECTURE 9 19
(2) Control in the transmission
path
The change in the transmission path will increase the
length of travel for the wave and get
absorbed/refracted/radiated in the surrounding
environment.
The available techniques are:
(a) Installation of barriers
(b) Installation of panels or enclosures
(c) Green belt development

20. PH 0101 UNIT 1 LECTURE 9 20
(a) Installation of barriers
• Installation of barriers between noise source and
receiver can attenuate the noise levels.
• The barrier may be either close to the source or
receiver,subjected to the condition that, R<< D or in
other words, to increase the transverse length for
the sound wave.

21. PH 0101 UNIT 1 LECTURE 9 21
R D
Source
ReceiverBarrier
Barrier close to source

22. PH 0101 UNIT 1 LECTURE 9 22
D
Barrier
Receiver
Source
R
Barrier close to receiver

23. PH 0101 UNIT 1 LECTURE 9 23
(b) Installation of panels or
enclosures
• A sound source may be enclosed with a paneled
structure such as room as a means of reducing the
noise levels at the receiver.
• The actual difference between the sound pressure
levels inside and outside an enclosure depends not
only on the transmission loss of the enclosure
panels but also on the acoustic absorption within the
enclosure and the details of the panel penetrations
which may include windows or doors.

24. PH 0101 UNIT 1 LECTURE 9 24
(c) Green Belt Development
• Green belt development can attenuate the
sound levels.
• The degree of attenuation varies with
species of greenbelt.
• The statutory regulations direct the
industries to develop greenbelt four times
the built-up area for attenuation of various
atmospheric pollutants, including noise.

25. PH 0101 UNIT 1 LECTURE 9 25
(3)Using protection equipment
• Protective equipment usage is the ultimate step in
noise control technology, i.e. after noise reduction at
source and/or after the diversion or engineered
control of transmission path of noise.
• The usage of protective equipment and the worker’s
exposure to the high noise levels can be minimized
by following.
(a) Job rotation
(b) Exposure reduction
(c) Hearing protection

26. PH 0101 UNIT 1 LECTURE 9 26
(a) Job rotation
By rotating the job between the workers working
at a particular noise source , the adverse
impacts can be reduced.
(b) Exposure reduction
The schedule of the workers should be planned in such a
way that, they should not be over exposed to the high
noise levels.
(c) Hearing protection
Equipment like earmuffs, ear plugs etc. are the commonly used
for hearing protection.Attenuation provided by ear-muffs vary
widely in respect to their size, shape, seal material etc.

27. What can I do to make a difference??
• Persuade
• Taking the help of police.
• Observe car free day on 22nd
of September.
• Creating awareness about the ill effects of noise
pollution.
• Promising oneself not to be the part of pollution
creator.

28. References:-
• www.edugreen.teri.res.in/explore/air
• http://en.wikipedia.org/wiki/Air_pollution
• www.controlairpollution.com
• Environmental studies by R. Rajgopalan
• www.nlm.nih.gov/medlineplus/airpollution