NON IONIZING RADIATION

ANKUR SHARMA12IH401, MIHS

www.ankur-mihs.blogspot.in

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Non-Ionzing Radiation:Refers to those electromagnetic radiation which are not energetic enough to cause ionization in matter.

Introduction

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Non-Ionizing Radiation• Non-ionizing radiation refers to any type of

electromagnetic radiation that does not carry enough energy per quantum to ionize atoms or molecules—that is, to completely remove an electron from an atom or molecule.

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Non-Ionizing radiation• Non-Ionizing radiation (NIR) refers to radiative

energy that, instead of producing charged ions when passing through matter, has sufficient energy only for excitation.

• The NIR spectrum is divided into two main regions, Optical Radiations and Electromagnetic Fields.

• The Optical can be further sub-divided into ultraviolet, visible, and infra-red

• The Electromagnetic Fields are further divided into radiofrequency (microwave, very high frequency and low frequency radio wave)

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Non Ionizing Radiation source

• Non-ionizing radiation originates from various sources:

• Natural origin (such as sunlight or lightning discharges etc.) And

• Man-made (seen in wireless communications, industrial, scientific and medical applications).

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Optical Radiations-Sources• The optical radiations are centred around visible light;

those with higher energies are termed UV radiation and those with lower energies IR radiation.

• Sources of UV radiation are the sun, arc welding, oxy-gas welding, sun lamps, lasers (UV), sterilization (germicidal) lamps, low pressure gas discharge lamps, high pressure discharge lamps.

• Sources of IR radiation are from hot processes such as steelmaking, glassmaking, welding, and also lasers (IR). The application of laser as a coherent light source is increasing rapidly.

• Medical applications include UV and neonatal phototherapy, surgical and therapy lasers, physiotherapy heat lamps

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Electromagnetic fields-Sources• Microwaves are used in telecommunications,

radar/satellite links, mobile phones, microwave ovens, TV transmitters.

• RF is used in radio communications, visual display units, television sets.

• Extremely low-frequency (ELF) electric and magnetic fields (EMFs) surround electrical machinery, home appliances, electric wiring, and high-voltage electrical transmission lines and transformers.

• Medical applications include: microwave hyperthermia, therapeutic and surgical diathermy, and magnetic resonance imaging (MRI).

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NIR Biological Effects

• The basics of biological effects seen with NIR relevant to human health is reviewed, including the optical cause biological effects of photochemical and heating; the electromagnetic fields leads to surface heating, electrical burn and shock.

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Electromagnetic Spectrum and associated Biological Effects

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The Electromagnetic Spectrum• Energy is proportional to frequency and is inversely

proportional to wavelength• Inherent energy defines the transition between

ionizing and non-ionizing radiations

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The Electromagnetic Spectrum

10-14 10-12 10-10 10-8 10-6 10-4 10-2 1 102 104 106 108

Wavelength in Meters

1010 108 106 104 102 1 10-2 10-4 10-6 10-8 10-10 10-12 10-14

Broadcast

Short waveTV

FM

RadarInfrared

Near Far

Visible

UltravioletX Rays

Gamma Rays

Cosmic Rays Power Transmission

Ionizing Radiation Nonionizing Radiation

Energy - Electron VoltsHigh Low

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What is Non-ionizing Radiation?

Non-ionizing radiation is radiation that does not "ionize an atom"

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Types of Non-Ionizing Radiation

1.0 Optical Radiation- Ultraviolet,- Infrared and - Visible (including lasers)2.0 Radiofrequency Radiation- Microwaves- Radiofrequency and - Extremely Low Frequency.09:06:41 AM 13

EMWRadar Waves

Gammarays

U.V.

I.R.

Visible LightMobile

and Micro waves

T.V. waves

X-rays

Radio Waves09:06:41 AM 14

NON-IONIZING RADIATIONBIOLOGICAL EFFECTS

• Ultraviolet light• Visible light• Infrared radiation• Microwaves• Radio & TV• Power transmission

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Non-Ionizing Examples• Ultraviolet – Black light – induce fluorescence in

some materials• Vision – very small portion that animals use to

process visual information • Heat – infrared – a little beyond the red

spectrum• Radio waves – beyond infrared• Micro waves• Electrical power transmission – 60 cycles per

second with a wave length of 1 to 2 million meters.

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UV Radiations-Source

• Sun lightMost harmful UV is absorbed by the atmosphere – depends on altitude

• Fluorescent lamps• Electric arc welding - can damage the eye

(cornea)Sources: Sun, mercury lamps, welding, lasers, pest

control (fly lamps), fluorescent lighting• Target organs: Skin, Eyes, Immune System

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Ultra-Violet Interaction

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Ultraviolet Interaction• The near Ultraviolet is absorbed very strongly in the surface

layer of the skin by electron transitions. As you go to higher energies, the ionization energies for many molecules are reached and the more dangerous photoionization processes take place.

• Sunburn is primarily an effect of UV, and ionization produces the risk of skin cancer.

• The ozone layer in the upper atmosphere is important for human health because it absorbs most of the harmful ultraviolet radiation from the sun before it reaches the surface.

• The higher frequencies in the ultraviolet are ionizing radiation and can produce harmful physiological effects ranging from sunburn to skin cancer.

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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

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Infrared Radiation• The quantum energy of infrared photons is in the range 0.001

to 1.7 eV which is in the range of energies separating the quantum states of molecular vibrations.

• Infrared is absorbed more strongly than microwaves, but less strongly than visible light. The result of infrared absorption is heating of the tissue since it increases molecular vibrational activity.

• Infrared radiation does penetrate the skin further than visible light and can thus be used for photographic imaging of subcutaneous blood vessels.

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IR Sources

• SOURCES: most are thermal sources (plasma torches, halogen lamps)

• Target Organs: skin and eyes

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Infrared Radiation Effects Energy between 750 nm to 0.3 cm The energy of heat – Heat is the transfer of energy Can damage – cornea, iris, retina and lens of the eye

(glass workers – “glass blower’s cataract”) 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 it09:06:42 AM 23

Microwave Sources

• Sources:– Radar– Communications. – TV– Heating and drying– Air traffic control

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Microwaves & Radio Waves

• Energy between 0.1 cm to 1 kilometer• Varity of industrial and home uses for

heating and information transfer (radio, TV, mobile phones)

• Produced by molecular vibration in solid bodies or crystals

• Health effects – heating, cataracts• Long-term effects being studied

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Microwaves InteractionThe quantum energy of microwave photons is in the range 0.00001 to 0.001 eV

which is in the range of energies separating the quantum states of molecular rotation and torsion.

The interaction of microwaves with matter other than metallic conductors will be to rotate molecules and produce heat as result of that molecular motion. Conductors will strongly absorb microwaves and any lower frequencies because they will cause electric currents which will heat the material.

Most matter, including the human body, is largely transparent to microwaves. High intensity microwaves, as in a microwave oven where they pass back and forth through the food millions of times, will heat the material by producing molecular rotations and torsions.

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Microwave Radiation

• The wavelength of microwave radiation ranges from about 10 microns to 1 meter

• Microwaves have very low energies and very long wavelengths

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Microwave Radiation

• Microwave radiation has many uses, including:– Cellular phones– Highway speed control– Food preparation

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Biological Effects [Microwaves]

• Primarily thermal effects• Capable of forming cataracts• CNS, biochemical changes? • Secondary problems (pace-makers, etc.)

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Biological Effects of NIR

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Biological Effects

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WHY EMF IS HARMFUL?WHY EMF IS HARMFUL?A. Alters permeability of the blood brain barrier thus

allows the transfer of toxins from blood to brain. B. Enhances the appearance of many diseases.C. Alters biological cycles.D. Alters hormone levels, E. Cause chromosomal damage, infertility. F. Causes cataracts and eye problems. G. Alters moods.H. Alters learning abilityI. Release of more adrenaline in most people within

15 minutes. J. Increases rate of cancer-cell divisionK. Leukemia and other cancers increase greatly

among people living near overhead power cables