Meteorology and Radiation

Category: Education

Presentation Description

No description available.


Presentation Transcript

Radiation and Meteorology:

Radiation and Meteorology Dr.N.Bayapa Reddy MD Asst. Professor Community Medicine Chennai Medical College

Radiation :


Definition of Radiation:

Definition of Radiation “Radiation is an energy in the form of electro-magnetic waves or particulate matter, traveling in the air.”

Slide 4:

Radioactivity: Elements & Atoms Atoms are composed of smaller particles referred to as: Protons Neutrons Electrons


Radioactivity If a nucleus is unstable for any reason, it will emit and absorb particles. There are many types of radiation and they are all pertinent to everyday life and health as well as nuclear physical applications .

Slide 6:

Ionization Ionizing radiation is produced by unstable atoms. Unstable atoms differ from stable atoms because they have an excess of energy or mass or both. Unstable atoms are said to be radioactive. In order to reach stability, these atoms give off, or emit, the excess energy or mass. These emissions are called radiation.

Slide 7:

The electro-magnetic waves vary in their length and frequency along a very wide spectrum.

Slide 9:

The total natural radiation to which the person is subjected to 0.1 rad a year

Types of Radiation:

Types of Radiation Radiation is classified into: Corpuscular - alpha, beta, proton… Electro magnetic –X rays, gamma, Uv , IR based on wavelength Ionizing radiation Non-ionizing radiation

Slide 12:

Types or Products of corpuscular Radiation   neutron

Slide 13:

Gamma Rays Gamma Rays (or photons): Result when the nucleus releases energy, usually after an alpha, beta or positron transition X-rays are photons (Electromagnetic radiations) emitted from electron orbits .

Slide 14:

Ionizing Versus Non-ionizing Radiation Ionizing Radiation Higher energy electromagnetic waves (gamma) or heavy particles (beta and alpha). High enough energy to pull electron from orbit. E.g. X-rays, Gamma, Cosmic Non-ionizing Radiation Lower energy electromagnetic waves. Not enough energy to pull electron from orbit, but can excite the electron. E.g. Uv , Infrared, Micro wave


QUANTIFICATION OF RADIATION A. Quantifying Radioactive Decay B. Quantifying Exposure and Dose

A. Quantifying Radioactive Decay:

A. Quantifying Radioactive Decay Measurement of Activity in disintegrations per second (dps); 1 Becquerel (Bq) = 1 dps; 1 Curie (Ci) = 3.7 x 1010 dps; 1 Becquerel (Bq) = 27Picocuries Activity of substances are expressed as activity per weight or volume (e.g., Bq/gm or Ci/l).

B. Quantifying Exposure and Dose:

B. Quantifying Exposure and Dose Exposure: Roentgen 1 Roentgen (R) = amount of X or gamma radiation that produces ionization resulting in 1 electrostatic unit of charge in 1 cm3 of dry air .  Instruments often measure exposure rate in mR/hr. Absorbed Dose : rad (Roentgen absorbed dose) = absorption of 100 ergs of energy from any radiation in 1 gram of any material ; 1 Gray (Gy) = 100 rads = 1 Joule/kg; Exposure to 1 Roentgen approximates 0.9 rad in air. Biologically Equivalent Dose : Rem (Roentgen equivalent man) = dose in rads x QF , where QF = quality factor. 1 Sievert (Sv) = 100 rems.

Slide 18:

External/Internal Exposure Limits for Occupationally Exposed Individuals Annual Dose Limits Adult (>18 yrs) Minor (< 18 yrs) Whole body* 5 rad/yr 500 mrem/yr Lens of eye 15000 mrem/yr 1500 mrem/yr Extremities 50000 mrem/yr 5000 mrem/yr Skin 50000 mrem/yr 5000 mrem/yr Organ 50000 mrem/yr 5000 mrem/yr

Community Emergency Radiation:

Community Emergency Radiation Hazardous Waste Sites: Radiation above background (0.01-0.02 m rem/hr) signifies possible presence which must be monitored. Radiation above 2 m rem/hr indicates potential hazard. Evacuate site until controlled.

Slide 20:

HEALTH EFFECTS Generalizations : that destroys the capacity for cell reproduction or division or causes cell mutation. A given total dose will cause more damage if received in a shorter time period. Acute Somatic Effects : person acutely exposed severity depends on dose. Death usually results from damage to bone marrow or intestinal wall. a dose of 400-500 roentgens on the whole body is fatal about 50% of cases. A dose of 25-50 roentgens on the whole body was found to be effect white blood cells, lassitude and softening of muscle. Acute radio-dermatitis is common in radiotherapy; chronic cases occur mostly in industry.

Slide 21:

Ionizing Radiation at the Cellular Level Causes breaks in one or both DNA strands or; Causes Free Radical formation

Slide 22:

Delayed Somatic Effects : Cancer, leukemia, cataracts, life shortening from organ failure, and abortion. cancer is approximately 10-100 rems. Foetal development abnormalities Shortening of life Genetic Effects : In off-spring effects are irreversible and always harmful. Dose for chromosomal mutation is approx 50-80 rems. Point mutation rate is approx. 10-100 mutations per million population per generation.

Slide 23:

Critical Organs : most susceptible organs to radiation are Lymphocytes, bone marrow, gastro-intestinal, gonads, and other fast-growing cells. The central nervous system is relatively resistant. The organs sensitive to specific radiation e.g., isotopes of iodine concentrate in the thyroid gland. These organs are considered "critical" for the specific nuclide.

Slide 24:

0-25 No observable effect. 25-50 Minor temporary blood changes. 50-100 Possible nausea and vomiting and reduced WBC. 150-300 Increased severity of above and diarrhea, malaise, loss of appetite. 300-500 Increased severity of above and hemorrhaging, depilation. Death may occur > 500 Symptoms appear immediately, then death has to occur. ACUTE DOSE(RAD) EFFECT

Effects by non ionizing radiation :

Effects by non ionizing radiation Radiofrequency Ranges (10 kHz to 300 GHz) Effects only possible at ten times the permissible exposure limit Heating of the body (thermal effect) Cataracts Some studies show effects of teratoginicity and carcinogenicity.


RADIATION CONTROLS A. Basic Control Methods for External Radiation Decrease Time Increase Distance Increase Shielding

Slide 27:

Radiation Protection Time : Minimize time of exposure to minimize total dose. Rotate employees to restrict individual dose. Distance : Maximize distance to source to maximize attenuation in air. The effect of distance can be estimated from equations. Shielding : Minimize exposure by placing absorbing shield between worker and source. Protective measures : lead rubber aprons. Lead aprons (0.5mm of lead) reduce the intensity of scattered x rays exposure. Periodic medical checkup

B. Monitoring :

B. Monitoring Personal Dosimeters : Normally they do not prevent exposures (no alarm), just record it. They can provide a record of accumulated exposure for an individual worker over extended periods of time (hours, days or weeks), and are small enough for measuring localized exposures Common types: Film badges; Thermoluminescence detectors (TLD); and pocket dosimeters.

Slide 29:

Continuous Monitors : Continuous direct reading ionization detectors (same detectors as above) can provide read-out and/or alarm to monitor hazardous locations alert workers to leakage, thereby preventing exposures . Long-Term Samplers : Used to measure average exposures over a longer time period.

Other Manmade Sources of Non-Ionizing Radiation:

Other Manmade Sources of Non-Ionizing Radiation

Radiation Protection Program :

Radiation Protection Program Monitoring of exposures : Personal, area, and screening measurements; Medical/biologic monitoring. Task-Specific Procedures and Controls : Initial, periodic, and post-maintenance or other non-scheduled events. Engineering (shielding) Emergency procedures : Response, "clean-up", post clean-up testing and spill control. Training and Hazard Communications including signs, warning lights, lockout/tagout, etc. Criteria for need, design, and information given. Material Handling : Receiving, inventory control, storage, and disposal.

Meteorological Environment :

Meteorological Environment Elements Atmospheric pressure Air temperature Humidity Rainfall Direction and speed of wind Movement of clouds and character of wether

Atmospheric pressure :

Atmospheric pressure One atmosphere of pressure =760mm of Hg The atmospheric pressure falls as altitude increases and rises altitude decreases At an altitude of 100,000 feet above mean sea level, the atmospheric pressure is less than 10 mm of Hg The pressure increases at a rate of 1 atmosphere for each 33 feet depth

Measurement :

Measurement Barometers Fortin’s barometer Kew Pattern Station Barometer Barograph

Effects on Health:

Effects on Health High altitude Exposed to low pressure Increase in respiration Increase in the concentration of Haemoglobin Increase in cardiac output Acute mountain sickness High altitude pulmonary oedema

Slide 42:

Low altitude High pressure Atmospheric pressure increases by one atmosphere for every 33 feet depth. Caisson’s disease

Air Temperature:

Air Temperature The factors which influence the temperature Latitude of the place Altitude Direction of wind Proximity to sea The temperature of the ground surface is always higher than that of the air


Measurement Mercury thermometer Alcohol thermometer Essential conditions for the use of the thermometers The air should have free access to the bulbs of the thermometer Should be protected against radiant heat

Dry bulb Thermometer:

Dry bulb Thermometer It is mounted on the Stevenson screen at a height 1.2-1.8 m above the ground level. Screen protects against radiant heat, direct sun and rain

Slide 46:

Wet Bulb Globe Temperature: Wet Bulb Globe Temperature Wet Sensor (muslin cloth) assesses evaporation (humidity & air movement) -as distilled water evaporates from cup, it cools the sensor Globe Sensor assesses radiant component Bulb Sensor assesses ambient temperature

Slide 47:

Wet bulb thermometer Maximum thermometer Minimum thermometer Six’s maximum and minimum thermometer Globe thermometer Wet globe thermometer Silvered thermometer Kata thermometer

Kata thermometer:

Kata thermometer Kata =down (Greek) Its an alcohol thermometer Glass Bulb 4cm long 1.8cmin diameter Marked from 100 0 to 95 0 F Two thermometers are used, the bulb of one is covered with a wet muslin cloth Before taking the readings the bulbs are immersed in hot water to warm them slightly above 130 0 Both the instruments are suspended in air at the point of observation.

Slide 49:

The temperature in seconds required for the spirit to fall from 100 0 - 95 0 F is noted with stop watch repeated at least 4 times Avg of last three readings The length of time depends upon the cooling power of the air Kata factor is determined for each instruments by manufacturer This factor is divided by the avg cooling time gives the rate of cooling in mill calories per sq.centimeter per second

Heat stress indices:

Heat stress indices Equatorial comfort index Heat stress index Predicted 4 hour sweat rate

Effects of heat stress :

Effects of heat stress Heat Stroke: Stroke Extreme exposure to temperature leads to failure of heat regulation leads to delirium, convulsion, coma and Death dry skin, absent of sweat, rhabdomyolysis, bleeding diathesis. Treatment :- Immediate cooling of the body up to the reaches of rectal temperature 102oF and Medical care for hypovolaemia, hypocalcaemia,, hyperkalaemia Heat Hyper pyrexia : temperature responses control fails temp above 106oF Heat cramps :- person doing heavy muscular work under the high temperature and humidity leads to loss of Na + and Cl -

Slide 52:

Heat Exhaustion: Exhaustion Prolonged sweating Illness induced dehydration Thirst Weakness Headache Dizziness Uncoordinated Cool down Re-hydrate Syncope: Prolonged standing in the sun Pooling of blood in lower limbs leads to decrease cardiac out and lowering blood supply to brain leads to Blurred vision Fainting collapses suddenly Treatment :- Lie down and Re-hydrate

Preventive measures:

Preventive measures Replacement of water Regulation of work Clothing Protective device Work environment

Slide 54:

Global Warming By: Ashley Grimes

Global warming:

Global warming Global Warming is an increase in global average surface temperature due to natural or anthropogenic climate change. The global surface area increase 1.330 F during the 20th century. Glaciers are melting rapidly Ocean temperatures have increased. Sea levels have risen almost one foot. The production and absorption of carbon dioxide and other greenhouse gases are not in balance.

Slide 56:

Causes of Global Warming The release of methane gas from arctic tundra and wetlands. Pollution is one of the biggest man made problems that leads to global warming. Burning fossil fuels Mining coal and oil emission of Green house gas CO2

Slide 57:

Pollution is one of the biggest man made problems that leads to global warming. Burning fossil fuels Green house gas CO2 Mining coal and oil

Slide 58:

Population More food, more methane, more burning of fossil fuels Manure Transportation

Slide 59:

Effects of Global Warming Rise in sea level Increase of ocean temperature Decrease of snow cover Increase of about 3 o C average global surface temp by 2030 Rise in the sea level of 0.1-0.3m by 2050

Slide 60:

Impact on Animals Birds laying eggs earlier Plants are flowering earlier Mammals are getting out of hibernation sooner

Slide 61:

Melting of ice in Greenland and Antarctica Increase in agriculture Water reservoirs drying up In humans, heat-related illnesses and increased breathing problems Chance of Malaria Extreme weather

Slide 62:

Personal Contribution to Global Warming I contribute to global warming by driving a car daily around campus and also driving home every other weekend. I also am part of the United States’ large population so I contribute to using more food, releasing more methane, and burning more fossil fuels.

Slide 63:

Solutions Invest in renewable energy Increase efficiency of cars Plant more trees


Humidity Humidity or moisture The amount of moisture which air can hold depends on its temperature Absolute Humidity Relative Humidity Measured by Dry and wet Hygrometer If both dry and wet thermometer showing same reading , it indicates atmosphere is 100% saturated

Slide 65:

Thank you