Risks and Hazards of EM Radiation

• Radiant Energy is the energy produced by nuclear reactions at the core of the sun. It is scientifically called electromagnetic radiation.
• Medium wavelengths from the sun are the visible radiation that we call sunlight.
• The radiation given off from the sun is called the solar spectrum.
• The effect of radiation on living organisms depends on how much energy it carries.
• Two basic carriers of radiation:

  • Particles
  • Waves
• Particles such as in the case of high-energy protons, neutrons, electrons, atoms, and ions.
• Waves, either light or sound.
• Man-made radiation sources:

  • tobacco
  • tv
  • x-rays
  • smoke detectors
  • lantern mantles
  • nuclear medicine
  • building materials
• Natural or background radiation sources:

  • radon
  • radioactive potassium
  • uranium, radium, and thorium
  • cosmic rays
• Radioactive Decay happens during the spontaneous change to be more stable.
• Half-life is the time required for half of the original population of radioactive atoms to decay.
• Ionizing Radiation is a damaging form of radiation which can create electrically-charged ions in the material it strikes.
• The ionization process can break apart atoms and molecules.
• X-rays and Gamma Rays: high-energy parts of the em spectrum
• Alpha Particles: atomic nuclei consisting of two protons and two neutrons
• Beta Particles: fast-moving electrons ejected from the nuclei of atoms
• Cosmic Radiation: energetic particles arriving at earth from outer space
• Neutrons: produced mainly in nuclear power plants
• Sievert: basic unit used to measure exposure to ionizing radiation
• Radiation exposure is expressed in millisieverts or microsieverts.
• In an older system, the unit of exposure is rem or roentgen equivalent man
• One sievert is one hundred times larger than one rem
• In nuclear power plants, radiation is created as a byproduct of electricity generation.
• Typically, 88% of ionizing radiation exposure to humans come from natural sources, most of the remaining 12% comes from medical procedures.
• An average person is exposed to 1000 microsieverts of whole body exposure per year.
• Ionizing Radiation can do the following:

  • Kill cancer cells
  • Cause cancer
  • Lead to sickness and death
  • Cause genetic mutations
• Different types of particle radiation sources:

  • Trapped particle radiation regions near Earth
  • Solar energetic particles
  • Galactic cosmic rays
  • Nova and supernova explosions
  • Quasars
• Solar energetic particles: high-energy particles emitted by the sun
• Galactic cosmic rays: high-energy particles created outside the solar system by stellar flares
• Stochastic Effects: long-term, low-level exposure to radiation; the chance of occurrence increases with the dose
• Non-stochastic Effects: cases of exposure to high levels of radiation and become more severe as the exposure increases
• Stochastic Effects Examples:

  • Cancer
  • Genetic Mutations
• Non-stochastic Effects Examples:

  • Cataracts
  • Skin Burns
  • Lowering of blood cell counts
• The most effective ways to protect against radiation are to limit exposure time, increase the distance from the source, or use shielding.