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NONIONIZING RADIATION. ….. a discussion of the health hazards associated with exposures to non-ionizing radiation. The Electromagnetic Spectrum. A name scientists give to a number of different types of radiation when they talk about them as a group
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NONIONIZING RADIATION ….. a discussion of the health hazards associated with exposures to non-ionizing radiation
The Electromagnetic Spectrum • A name scientists give to a number of different types of radiation when they talk about them as a group • Energy is proportional to frequency and is inversely proportional to wavelength • Inherent energy defines the transition between ionizing and non-ionizing radiations
Electromagnetic Spectrum • Electromagnetic Spectrum Video Clip Source: http://imagine.gsfc.nasa.gov/docs/science/know_l2/emspectrum.html
THE NON-IONIZING RADIATIONS • RF, (RADIO FREQUENCY) • MICROWAVES • INFRARED • VISIBLE (LASER) • ULTRAVIOLET • AND BEYOND
ULTRAVIOLET • Types: UV-A, UV-B, and UV-C • SOURCES: sun, mercury lamps, welding, lasers, pest control (fly lamps), fluorescent lighting • Target Organs: skin, eyes, immune system
Biological Effect [UV] • Aging of the skin • Reddening of the skin (erythema) • Skin cancer upon prolonged exposures • Corneal injury • Photosensitization (with some chemicals) • Benefits – Induces production of Vitamin D in skin
LASERS • Light Amplification by Stimulated Emission of radiation (LASER) • COHERENT • MONOCHROMATIC • DIRECTIONAL
Biological Effects [LASERS] • Primarily to the eye • retinal injury is most significant • Secondarily to the skin
INFRARED • SOURCES: most are thermal sources (plasma torches, halogen lamps) • Target Organs: skin and eyes
Biological Effects [Infrared] • Primarily thermal in nature • Skin: heats/burn surface of the skin and tissues immediately below • Eyes: Can damage retina and cornea, cause cataracts infrared: • Easiest to avoid: you can see it & feel it
MICROWAVE APPLICATIONS • Sources: • Radar • Communications. • TV • Heating and drying • Air traffic control
Biological Effects [Microwaves] • Primarily thermal effects • Capable of forming cataracts • CNS, biochemical changes? • Secondary problems (pace-makers, etc.)
RADIO FREQUENCY • What we said about microwaves applies for RF waves also, only to a lesser degree. • This area, and the extra low frequency (ELF) energies are getting a lot of attention right now!