Download - Noise & Radiation - health Effect
Dr.Shahid MahmoodAssistant Professor
Department of Community MedicineFJMC Lahore
Lect
ure
-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 ObjectivesAt 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
20
th C
en
tury
=
CEN
TU
RY
OF N
OIS
E
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 85dB
Frequency is no. of waves passing a point per unit time Higher f= High sound
Measured in Hertz(Hz) 1 Hz = 1 wave per secondHuman ear can hear: 20 Hz – 20,000 Hz < 20 = Infra –audible > 20,000 = ultrasonic Some animals can hear <20
Noise expressed in Psycho-acoustic term joining loudness and frequency = Phon
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 pitch Low
pitch
Usual Sound levels at various places
Acceptable Noise level (Standard)
Area Spot Sound Level (dBA)
Residential Bed roomLiving room
25
40
Commercial
Office ConferenceRestaurant
35-45
40-45
40-60
Industrial Workshop Laboratory
40-60
40-50
Educational
Class roomLibrary
35-40
30-40
Hospitals Wards 20-35
Noise Pollution Effect
Non-Auditory1. Speech disturbance (traffic, stations) – SIL 12dB 2. Annoyance : Irritation , Short temperedness, impatience3. 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 educated3. 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)
6. Legislation
Radiation is a process in which energetic particles or energetic waves travel through a medium or space
Radiation types
Ionizing radiation
(ability to penetrate tissues & deposit its
energy )
• Electromagnetic radiations
• X-rays (15-20cm) ; gamma rays (50cm)
• Corpuscular radiations
• Alpha particles (0.05mm) – more harmful
• Beta Particles (0.06-4mm)• Proton
Non-Ionizing radiation
( longer wavelength and low energy)
Ultraviolet radiations (UV) Visible light Infrared radiation microwave radiation radio-frequency radiation E
lectr
om
ag
ne
tic
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 rad
TV , computer, Mobile, Luminous markers, radioactive dial watches
Biological Effects of ionizing radiationBiological 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
hazard2. 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
5. Periodic Medical examination of radiological Deptt. Workers ; Job rotation , holidays
X-ray department hygiene
Education
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 sitesAgreement on reducing nuclear weaponsSafe operation of nuclear power plants