Non-Ionizing Radiation: Sources, Health Effects & Protection

Item 18. Non-ionizing Radiation

Non-ionizing radiation is radiation that is not capable of producing ions when interacting with atoms of a material. It is characterized by low frequency and small photon energy (<1.23 meV).

Main Types

They fall into two main groups:

• Microwave (MW) and radio frequency (RF)
• Visible and near

Public Health Concern

In May 1996, in response to growing concern in many Member States about the potential public health effects of exposure to electric and magnetic fields emitted by increasingly numerous and diverse sources, the World Health Organization launched an international project to assess the health and environmental effects of exposure to these fields. This became known as the International EMF Project.

Units

• Electric field: V/m or kV/m
• Magnetic-flux density: microteslas or milligauss
• Power density: mW/mm²

Sources of Microwave and Radio Frequency Radiation

• Radio stations
• Radio & TV
• Radar installations
• Radio systems
• Microwave ovens
• Equipment used in welding and fusion
• Sterilization, etc.

Biological Effects

The biological effects depend on several factors, including:

• Density of the induced fields (power density)
• Absorptive capacity of the organism
• Frequency — more risk in the 30–300 MHz range
• Absorption location: upper limb, trunk
• Degree of vascularization of organs and tissues

Health Effects

Health effects are commonly grouped into thermal and non-thermal effects:

• Thermal: when people absorb radiation and it is transformed into heat. Effects may include:
  • Hyperthermia
  • Burns
  • Cataracts
  • Sterility
• Non-thermal:
  • Cellular, genetic and chromosomal transformations
  • Effects on the hematopoietic system
  • Changes in heart rate and blood pressure
  • Endocrine disorders and neuro-endocrine effects
  • Effects on hearing
  • Changes in the behavior of individuals
  • Electroencephalographic abnormalities

Optical Radiation

Optical radiation can include infrared, visible light and ultraviolet radiation. Such radiation can cause thermal and photochemical effects on the human body.

Ultraviolet Radiation Sources

• Germicidal lamps, phototherapy or UVA
• Arc welding and cutting
• Photocopiers
• Mercury vapor lamps, gas, hydrogen and deuterium lamps, tungsten halogen, fluorescent lamps

Negative Effects of Optical Radiation

When optical radiation is incident on a body it can be reflected, transmitted or absorbed, resulting in photochemical reactions. It produces biological effects of a thermal type and can cause irritation of the skin and eyes.

Protection and Workplace Measures

Every worker subject to harmful ultraviolet or other optical radiation shall be educated, both verbally and in writing, about the risks and the appropriate means of protection.

• Exposed workers should wear appropriate clothing to cover exposed skin parts, especially the face and eyes.
• Arc welding operations shall be performed in individual booths; if this is not possible, noncombustible shields or curtains should be placed around the site.

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