Noise & radiation health effects

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lecture -8 , communty Medicine FJMC

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  • made up of changes in air pressure in the form of waves. Frequency is the property of sound that most determines pitch.[3] The frequencies an ear can hear are limited to a specific range of frequencies.Mechanical vibrations perceived as sound travel through all forms of matter: gases, liquids, solids, and plasmas. The matter that supports the sound is called the medium. Sound cannot travel through a vacuum.The audible frequency range for humans is typically given as being between about 20 Hz and 20,000 Hz (20 kHz). High frequencies often become more difficult to hear with age. Other species have different hearing ranges. For example, some dog breeds can perceive vibrations up to 60,000 HzA sound wave is a periodic variation in air pressure.Distance between two consecutive crests or troughs.Pitch is an auditoryperceptual property that allows the ordering of sounds on a frequency-related scale.
  • Sound, like all waves, has properties which allow us to tell the difference between seperate sound waves.Vibrations Vibrations is where sound is created it is the source of all sound. When vibrating objects push together they create little zones of compressed air. When the zones of compressed air are released they spring out causing zones of compression and refraction that travel outward from the source. Which creates sound waves.Wavength  Amplitude Amplitude is the maximum distance a particle moves from its resting position. Amplitude is also the height of a sound wave. A quiet sound has a lower amplitude and a loud sound has a higher amplitude.   Speed  Volume  Resonance
  • X-ray and gamma rays are short wavelength , but deep penetrating so used for diagnostic and therapeutics. Alpha particles are more dangerous when substance inhaled or through wound. X-rays are man made whereas gamma are emitted from radioactive substances. There is no difference between these two .cosmic rays also contains ionizing radiation.
  • Number of ions produced in 1 ml of air is roentgen. Amount of radioactive energeyabsored per gram of tissue . Rem is the absorbed dose and modifying factor.
  • Natural background radiation arises from three sources: cosmic radiation from outer space, weaken as enter our atmosphere. Terrestrial radiation comes from radioactive material such as uranium , thorium, in soil, rocks, . Atmospheric radiation from gases like radon, thoron. Internal radiation in man from small amount of radioactive material stored in body like uranium, thorium and isotopes of potassium, strontium 90, K 40, Most important exposure is the man made. People exposed to the x-rays are the pateinets, medical (0.02-3 rad per years). Half life of sr90 is 28 years .
  • Dose of 400-500 reoentgen is fatal for 50% exposed. 25 gives rise to lassitude, WBC breakdown. Acute effect range ofrom nausea , vomiting and bleeding
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  • Noise & radiation health effects

    1. 1. Environmental HealthLecture - Noise & Radiation8 EFFECTS ON HEALTH Dr.Shahid Mahmood Assistant Professor Department of Community Medicine FJMC Lahore
    2. 2. Acknowledgement Park K. Textbook of Preventive and Social Medicine Maxcy- Rosenau-Last. Public health and Preventive Medicineo World Health Organization (WHO) Iliyas-Shah-Ansari . Public health and Community Medicine www.google.com/images
    3. 3. Learning ObjectivesAt the end of this session, Students willbe 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
    4. 4. Sound is the sequence of pressure waves producedby oscillations, propagated through Medium(Solids, gas, liquids) Wavelength
    5. 5. 20th Century = CENTURY OF NOISE Noise ‘Definition’ Stress factor Wrong Sound In Wrong Place At Wrong Time Unwanted Sound?? Subjective ??
    6. 6. Noise – Properties Loudness / Intensity Frequency Depends on Amplitude of  Frequency is no. ofvibrations waves passing a point per unit time Measured in decibels Higher f= High sound(dB) 50 dB means that sound Measured in Hertz(Hz)is 50 times more intense 1 Hz = 1 wave perthan lowest seconddistinguishable (reference) Human ear can hear:sound 20 Hz – 20,000 Hz < 20 = Infra –audibleUpper tolerable limit isterm joining 20,000 and frequency =Noise expressed in Psycho-acoustic > loudness = ultrasonic
    7. 7. Sources of Noise in Environment Automobile (Pressure Horns) Factories (Machines/ Vibratingtools) Air crafts & trains Musical instruments Human voices (class room…?) Mega Phones use , Mobiletones TV , radio , Loud speakers
    8. 8. Noisy spots (Noise Pollutedareas)  Bus terminals  Traffic congested area  Air ports  Railway lines  Area of festivity  Music shows
    9. 9. Measuring Sound / Noise levelsSound level meter measure the sound/noise on aweighted curve called Curve A - Expressed as dB [A] Sound level meters
    10. 10. Octave band Analyzer with computer program High Low pitch pitch Audiometer and its tracing
    11. 11. Usual Sound levels at variousplaces
    12. 12. Acceptable Noise level(Standard) Area Spot Sound Level (dBA) 25Residential Bed room Living room 40 35-45Commercial Office Conference 40-45 Restaurant 40-60 40-60Industrial Workshop Laboratory 40-50 35-40Educational Class room Library 30-40 20-35Hospitals Wards
    13. 13. Noise PollutionAuditory EffectAuditory fatigue – 90 dB ; 4000 Hz (buzzing &whistling in ears )Deafness (hearing loss)Temporary [ Sudden exposure; 24 hours; 4000-6000Hz ]Permanent [ Chronic exposure >100dB; affectinternal ear, organ of corti; rupture of tympanicmembrane (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,
    14. 14. Principles of Noise ControlSound abatement methods(reducing sound generation andtransmission)1. Sound Insulation : reducing transmission by introducing barrier – Thick glass , concrete material2. Sound Absorption – tiles , forms and fiber-glass3. Vibration dumping - Application of material of surface- wooden plateform
    15. 15. Noisy spots (Noise Pollutedareas)  Bus terminals  Traffic congested area  Air ports  Railway lines  Area of festivity  Music shows
    16. 16. 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
    17. 17. 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 buildings4. Reducing sound generation at various industrial activity spots
    18. 18. Noise control Measures3. Periodic monitoring- sound levels both in industrial and residential areas for surveillance4. Periodic examination of workers in noisy working conditions , rotating their jobs, proving them protective gadgets5. Health education (community)
    19. 19. Radiation is a process in which energetic particlesor energetic waves travel through a medium or
    20. 20. Radiation types Ionizing • Electromagnetic radiations radiation • X-rays (15-20cm) ; gamma rays (ability to (50cm) penetrate • Corpuscular radiations tissues & • Alpha particles (0.05mm) – more deposit its harmful energy ) • Beta Particles (0.06-4mm) • Proton ElectromagneticNon-Ionizing  Ultraviolet radiations (UV) radiation  Visible light ( longer Infrared radiationwavelength and  microwave radiation low energy)  radio-frequency radiation
    21. 21. 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 = SievertDose equivalent (Sievert ) ‘ Sv’ = D (absorbed dose- Gy) x Q (quality factor) [ Value of Q factor for X-rays = 1 & Particles = 20 ]
    22. 22. Natural background radiation
    23. 23. Sources of Radiation exposure Natural Man- Made SourcesCosmic rays Medical & dental X-rays , Radio-isotopesEnvironmental Occupational ExposureAtmospheric (Radium / uranium )TerrestrialInternal Nuclear accidentsPotssium -40 (Chernobyl)Carbon-14 Exposure for many yearsTotal natural radiation per TV , computer, Mobile,year exposure = 0.1 Luminous markers, radioactive dial watches
    24. 24. Biological Effects of ionizing radiation Radiation sickness Immediate Acute radiation syndrome Somatic ( Affect the Leukemia individual exposed) CarcinogenesisBiological effects Delayed Fetal development abnormalities Genetic Chromosomes Shortening of ( Affect next mutations life generation)
    25. 25. E Radiation Protection- Radiationd Hygieneu 1. Natural radiation of 0.1 rad pose no hazardc 2. Permissible dose for man-made is 5 rad pera X-ray department hygiene year.t 1. Unnecessary x-rays should be avoided (onei short = 4 rad), especially children /pregnanto womenn 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
    26. 26. International agencies working forRadiation 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 ofpracticePeriodic inspection of nuclear sitesAgreement on reducing nuclearweapons

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