1. Dr.Malik Muhammad Abdul Razzaq 1

2. Assistant Professor  Department of Community Medicine  Sheikh Zayed Medical College  Rahim Yar Khan Dr.Malik Muhammad Abdul Razzaq 2

3.  Noise is often defined as “unwanted sound”,  Noise is wrong sound in the wrong place, at the wrong time.  Noise has become a very important “stress factor”  Normal conversation produces a noise of 60-65 dB  Whispering, 20-30 dB;  Heavy street traffic 60-80 dB;  Boiler factories about 120 dB;  Normal tolerable limit is 85 dB; Dr.Malik Muhammad Abdul Razzaq 3

4.  Noise has two important properties: Loudness Loudness depends upon the amplitude of the vibrations which initiated the noise. The loudness of noise is measured in decibels (dB).  Frequency: The frequency is denoted as Hertz (Hz.) One Hz is equal to one wave per second. The human ear can hear frequencies from about 20 to 20000 Hz. This range is reduced with age and other subjective factos. Many animals (e.g., dogs) can hear sounds inaudible to the human ear. Dr.Malik Muhammad Abdul Razzaq 4

5. To signify the vast cacophony of sounds that are being produced in the modern life, are leading to health hazards. These hazardous effects are: 1. Auditory effects 2. Non-Auditory effects Dr.Malik Muhammad Abdul Razzaq 5

6. a. Auditory Fatigue:  It appear in the 90 dB region and greatest at 4000 Hz. b. Deafness:  The hearing loss may be temporary or permanent. Repeated or continuous exposure to noise around 100 decibels may result in a permanent hearing loss. c. Occupational hearing loss:  When there is exposure to noise above than 100 dB the result is hearing loss. Exposure to noise above 160 dB may rupture the tympanic membrane and cause permanent loss of hearing. Dr.Malik Muhammad Abdul Razzaq 6

7.  Interference with speech  Annoyance  Efficiency  Physiological changes  Economic loss Dr.Malik Muhammad Abdul Razzaq 7

8.  CAREFUL PLANNING OF CITIES  CONTROL OF VEHICLES  BUILDING ACOUSTIC INSULATION  INDUSTRIES AND RAILWAYS  PROTECTION OF EXPOSED PERSON BY USING EAR PLUGS, etc.  LEGISLATION  EDUCATION Dr.Malik Muhammad Abdul Razzaq 8

9.  RADIATION Radiation is part of man’s environment.  SOURCES:  The sources of radiation are man – made and natural  NaturalMan – Made  1. Cosmic rays1. Medical and dental X- rays, Radioisotopes  2. Environmental:2. Occupational exposure  a. Terrestrial 3. Nuclear:  b. Atmosphericradioactive fallout  3. Internal:4. Miscellaneous:  Potassium-40Television sets  Carbon – 14radioactive dial  Watches, Isotope tagged products, Luminous markers. Dr.Malik Muhammad Abdul Razzaq 9

10.  1. IONIZING RADIATION:  Is applied to radiation which has the ability to penetrate tissues and deposit its energy within them. Ionizing radiation may be divided in to two groups:  Electromagnetic radiations e.g., X- rays and gamma rays,  Corpuscular radiations e.g., alpha particles and beta particles (electrons) and protons.  Cosmic rays also contain ionizing radiations Dr.Malik Muhammad Abdul Razzaq 10

11. These are electromagnetic radiations of wavelength longer than those of ionizing radiation. All non-ionizing form of radiations have less energy than cosmic, gamma, and X-radiation. Dr.Malik Muhammad Abdul Razzaq 11

12.  Roentgen: Roentgen is the unit of exposure. It is now replaced by Coulomb per kilogram  Rad: Is the unit of absorbed dose. It is now replaced by SI units as Gray  Rem: Is the product of the absorbed dose and the modifying factors. The Rem indicates the degree of potential danger to health. Dr.Malik Muhammad Abdul Razzaq 12

13. 1. SOMATIC EFFEXTS  A dose of 400 to 500 roentgens on the whole body is fatal.  Immediate effects:  Radiation sickness  Acute radiation syndrome  Delayed effects:  i. Leukemia  ii. Carcinogenesis  iii.Foetal developmental abnormalities  iv. Shortening of life 2. GENETIC  Chromosome mutations  Point mutations Dr.Malik Muhammad Abdul Razzaq 13

14. 1. Avoiding Exposure to X-ray: Of the man – made sources, a dose of 4 rad is delivered a part of body when exposed to X-ray in about one minute. So unnecessary X-ray examination should be avoided in children and pregnant women. 2. Lead aprons:.5mm of lead apron will reduce the intensity of scattered X-ray over 90 per cent. Workers must wear a film badge or dosimeter which shows accumulated exposure to radiation. 3. Safe operation of nuclear power plants and enunciating the basic principles of radiation protection. Dr.Malik Muhammad Abdul Razzaq 14

15. Dr.Malik Muhammad Abdul Razzaq 15