Dr.Shahid Mahmood
Assistant Professor
Department of Community Medicine
FJMC Lahore
Lecture-
8
Environmental Health
Noise & Radiation
EFFECTS ON
HEALTH

Acknowledgement
 Park K. Textbook of Preventive and
Social Medicine
 Maxcy- Rosenau-Last. Public health
and Preventive Medicine
o World Health Organization (WHO)
 Iliyas-Shah-Ansari . Public health
and Community Medicine
 www.google.com/images

Learning Objectives
At the end of this session, Students will
be able to :
1. Define Noise and sources of Noise in
our surroundings.
2. Describe the sources of radiation, its
types and associated health hazards.
3. Explain the methods to prevent and
control the unhealthy effect from Noise
and Radiation

Sound is the sequence of pressure waves produced
by oscillations, propagated through Medium (Solids,
gas, liquids)
Wavelength

Noise ‘Definition’
Unwanted Sound??
Subjective ??
Wrong Sound
In Wrong Place
At Wrong Time
20thCentury=CENTURYOFNOISE Stress factor

Noise – Properties
Loudness / Intensity Frequency
 Depends on Amplitude of
vibrations
 Measured in decibels
(dB)
 50 dB means that sound
is 50 times more intense
than lowest
distinguishable (reference)
sound
Upper tolerable limit is
 Frequency is no. of
waves passing a point
per unit time
Higher f= High sound
Measured in Hertz(Hz)
1 Hz = 1 wave per
second
Human ear can hear:
20 Hz – 20,000 Hz
< 20 = Infra –audible
> 20,000 = ultrasonicNoise expressed in Psycho-acoustic term joining loudness and frequency =

Sources of Noise in
Environment
 Automobile (Pressure Horns)
 Factories (Machines/ Vibrating
tools)
 Air crafts & trains
 Musical instruments
 Human voices (class room…?)
 Mega Phones use , Mobile
tones
 TV , radio , Loud speakers

Noisy spots (Noise Polluted
areas)
 Bus terminals
 Traffic congested
area
 Air ports
 Railway lines
 Area of festivity
 Music shows

Sound level meter measure the sound/noise on a
weighted curve called Curve A - Expressed as dB [A]
Sound level meters
Measuring Sound / Noise levels

Octave band Analyzer with computer program
Audiometer and its tracing
High
pitchLow
pitch

Usual Sound levels at various
places

Acceptable Noise level
(Standard)
Area Spot Sound Level (dBA)
Residential Bed room
Living room
25
40
Commercial Office
Conference
Restaurant
35-45
40-45
40-60
Industrial Workshop
Laboratory
40-60
40-50
Educational Class room
Library
35-40
30-40
Hospitals Wards 20-35

Noise Pollution
EffectAuditory
Auditory fatigue – 90 dB ; 4000 Hz (buzzing &
whistling in ears )
Deafness (hearing loss)
Temporary [ Sudden exposure; 24 hours; 4000-6000Hz ]
Permanent [ Chronic exposure >100dB; affect
internal ear, organ of corti; rupture of tympanic
membrane (160dB); usually Occupational;
Non-Auditory
1. Speech disturbance (traffic, stations) – SIL 12dB
2. Annoyance : Irritation , Short temperedness, impatience
3. Reduction in work efficiency – economic loss
4. Physiological changes : Sleeplessness, increase pulse,
BP, Breathing , sweating , nausea,

Principles of Noise Control
Sound abatement methods
(reducing sound generation and
transmission)
1. Sound Insulation : reducing
transmission by introducing barrier
– Thick glass , concrete material
2. Sound Absorption – tiles , forms
and fiber-glass
3. Vibration dumping - Application of
material of surface- wooden plateform

Noisy spots (Noise Polluted
areas)
 Bus terminals
 Traffic congested
area
 Air ports
 Railway lines
 Area of festivity
 Music shows

Prevention and Control
(Noise pollution)
1. Proper Town Planning :
 Separate industrial, residential and traffic zones
 Wide green belts between main roads and
residences
 Wide roads to accommodate traffic

2. Control of vehicles and
Pressure horns
 Heavy vehicles – Not
allowed on narrow
street –traffic jam
 Pressure horns
prohibited , drivers
educated
3. Using insulation
material in buildings
4. Reducing sound
generation at various
industrial activity
spots

Noise control Measures
3. Periodic monitoring- sound
levels both in industrial and
residential areas for
surveillance
4. Periodic examination of
workers in noisy working
conditions , rotating their jobs,
proving them protective
gadgets
5. Health education (community)

Radiation is a process in which energetic particles
or energetic waves travel through a medium or

Radiation types
• Electromagnetic radiations
• X-rays (15-20cm) ; gamma rays
(50cm)
• Corpuscular radiations
• Alpha particles (0.05mm) – more
harmful
• Beta Particles (0.06-4mm)
• Proton
Ionizing
radiation
(ability to
penetrate
tissues &
deposit its
energy )
Non-Ionizing
radiation
( longer
wavelength and
low energy)
 Ultraviolet radiations (UV)
 Visible light
Infrared radiation
 microwave radiation
 radio-frequency radiation
Electromagnetic

Measuring radiation
Radioactivity Unit
No. of nuclear disintegration per unit time
of radioactive material
Unit of radioactive activity = Becquerel
(Bq)
1 Bq = 1 disintegration per second
Radiation Potency (strength of radiation)
1. Roentgen – unit of exposure
2. Rad – Unit of absorbed dose
3. Rem – Unit measuring Potential to health
A new International system(SI) of unit have now
replaced Roentgen= Coulomb ; Rad = Gray ;
Rem = Sievert
Dose equivalent (Sievert ) ‘ Sv’ = D (absorbed dose- Gy) x Q (quality factor)
[ Value of Q factor for X-rays = 1 & Particles = 20 ]

Natural background radiation

Sources of Radiation
exposure
Natural
Sources
Man- Made
Cosmic rays Medical & dental
X-rays , Radio-isotopes
Environmental
Atmospheric
Terrestrial
Occupational Exposure
(Radium / uranium )
Internal
Potssium -40
Carbon-14
Nuclear accidents
(Chernobyl)
Exposure for many years
Total natural radiation per
year exposure = 0.1
TV , computer, Mobile,
Luminous markers,
radioactive dial watches

Biological Effects of ionizing
radiation
Biological effects
Somatic
( Affect the
individual
exposed)
Immediate
Radiation
sickness
Acute radiation
syndrome
Delayed
Leukemia
Carcinogenesis
Fetal
development
abnormalities
Shortening of
life
Genetic
( Affect next
generation)
Chromosomes
mutations

Radiation Protection- Radiation
Hygiene
1. Natural radiation of 0.1 rad pose no hazard
2. Permissible dose for man-made is 5 rad per
year.
1. Unnecessary x-rays should be avoided (one
short = 4 rad), especially children /pregnant
women
2. Proper surveillance of X-rays plant ,
measurement of radiation in that area and
surrounding
3. Protection of workers using lead shield,
apron
4. Workers should wear film badge or
dosimeter showing accumulated exposure
X-ray department hygiene
E
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International agencies working for
Radiation Protection
 International Commission on
Radiological Protection (ICRP)
 International Atomic energy
Agency(IAEA)
 World health Organization (WHO )Peaceful use of Atomic energy
Develop standards and code of
practice
Periodic inspection of nuclear sites
Agreement on reducing nuclear
weapons