Noise pollution

What is noise pollution?

production of unwanted sounds that

are annoying, distracting or damaging to

one’s hearing.

Sources of noise pollution

• Street traffic

• Rail • Airplanes &

Rockets

• Constructions

• Consumer products

Level of tolerance

• Normal level of tolerance is 80dbA.

• Sound level below and above this is considered to be as noise pollution.

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.

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(1) It decreases the efficiency of a man 2) Lack of concentration3) Fatigue4) Health issues ( BP, Abortion etc)

Impact of noise on humans

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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.

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Impact of Noise on Animals

• Noise pollution damage the nervous system of animals.

• Animal looses the balance of its mind.

• It impacts breeding

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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.

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.

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.

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.

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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.

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(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

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(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.

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(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.

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(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.

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(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.

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.


(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


(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.


R D

SourceReceiverBarrier

Barrier close to source


D

Barrier

Receiver

Source

R

Barrier close to receiver


(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.


(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.


(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


(a) Job rotation By rotating the job between the workers working

at a particular noise source , the adverse impacts can be reduced.

(b) Exposure reductionThe 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.

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.

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

http://www.edugreen.teri.res.in/explore/air

http://en.wikipedia.org/wiki/Air_pollution

http://www.controlairpollution.com/

http://www.nlm.nih.gov/medlineplus/airpollution