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