Environmental Factor - Noise Pollution, Its Effects and Remedies

2. Environmental Engineering :
Noise Pollution
PREPARED BY :
PARTH DESANI

3. Contents
 What is noise and sound ?
 Difference between noise and sound
 Characteristics of sound
 Sources of noise pollution
 Effects of noise pollution
 Control of noise pollution

4. What is noise and sound ?
 Sound :
What we hear is known as sound.
 Noise :
The unwanted and unpleasant sound is known as
noise.

5. Difference between sound and
noise
Sound
1) Sound is what we hear.
2) It has a constant pitch or frequency.
3) It has a periodic motion.
4) It produces meaningful communication.
5) It’s unit is Hertz (Hz).
Noise
1) Noise is unwanted and unpleasant
sound.
2) It has a variable pitch or frequency.
3) It has a non periodic function.
4) It does not produce meaningful
communication.
5) It’s unit is decibel (dB).

6. Characteristics of sound
 Sound contains following characteristics in it :
 Frequency (f)
 Time Period (T)
 Intensity (I)
 Wavelength (λ)
 Sound Pressure
 Sound Power
 Sound Pressure Level
 Amplitude of Wave (A)

7. Sources of noise pollution
 The presence of unwanted and unpleasant sound in the
atmosphere, which may cause discomfort is called
noise pollution.
 The sources of noise pollutions are as follows :
 Traffic sources
 Industrial sources
 Constructional sources
 Other sources

8.  Traffic Sources :
 Noise created by various means of transport like trucks, tractors, buses,
autorickshaws, trains, aeroplanes, etc. are the traffic related sources of
noise pollutions.
 It may be in the form of,
- horn of vehicles
- raise of accelerator
- vehicle with damaged silencer
- noise produced by a diesel car will be more than produced by a
petrol car
- a jet aircraft will produce more noise than a propeller type of
aircraft

9.  Industrial sources :
 industrial noises are usually produced by :
- reciprocating or rotating machinery
- cutting of materials, grinding
- blow hammers
- generators
- high pressure and high velocity gases, etc.

10.  Constructional sources :
 Noise produced by various constructional activities are :
- rock crushers for production of aggregates
- pile driving equipments
- boring and drilling equipments
- road rollers
- material handling by belt conveyors, chute, hoist
- rock blasting

11.  Other sources :
 In residential area – loud voice of T.V.,
music systems, radio, etc.
 Public address systems – public
functions, navratri festival etc.
 Sirens – Police van, industries

12. Effects of noise pollution
 The major effects of noise pollution are :
 Physical effects
 Physiological effects
 Psychological effects
 Physical Effects :
 Loss of hearing – long time exposure of loud sound (80 – 90 dB) for more than 8 hours a day, may
cause loss in hearing.
 Total deafness (acoustic trauma).
 Sudden loudness particularly from crackers and explosions may affect the ear drum and sensitive
ear membrances.

13. Physiological Effects :
 Headache, nausea
 Dizziness, gastric ulcers
 High rate of heart beat
 Fluctuations in blood pressure and
sugar
Psychological Effects :
 Annoyance, sleep interference
 Depression fatigue
 Mental stress
 Speech interference
 Effects on performance
 Decrease in efficiency

15. Control of noise pollution
 Noise is a serious environmental pollution and health hazard. Noise
pollution can be effectively controlled by taking the following measures
:
 Control at receiver’s end
 Acoustic zoning
 Supression of noise at source
 Planting trees
 Sound insulation at construction stages
 Legislative measures

16.  Control at Receiver’s End :
 People working in a noisy installations, ear – protection aid like ear – plug, ear – muffs,
noise helmets, headphones, etc. must be provided to reduce occupational exposures.
 Acoustic Zoning :
 Silence zones near the educational, hospitals and residential area should required.
 Increasing distance between source and receiver of noisy industrial areas, bus terminals
and railway stations, aerodromes, etc. away from the residential areas would go a long
way in minimizing noise pollution.

17.  Supressions of Noise at source :
 If working methods are improved by :
- installing noisy machines in sound proof chambers
- proper maintenance and lubrications of machine
- use of sound absorbing materials for covering noise-producing machines
- use of silencers to control noise from automobiles, ducts, exhausts, etc
- designing, fabricating and using quieter machines to replace the noisy ones
- reducing noise from vibrating machines by vibration damping. i.e. damping
materials e.g. rubber, neoprene, cork and plastic beneath the machine

18.  Planting Trees :
 Planting green trees along the roadside, near hospital, schools, educational institutions
etc. help in noise reduction.
 Sound insulation at construction stages :
 Gap between the door and wall should be packed with sound absorbing materials.
 In noise proof recording rooms, acoustical tiles, perforated plywood etc. can be fixed on
walls and ceiling etc.

19.  Legislative measures :
 Strict legislative measure need to be enforced to
reduce noise pollution.
- framing a separate Noise Pollution Act
- minimum use of loud speakers and amplifiers
especially near silence zones.