Health consequences – Background

 

Non-ionizing radiation may be classified according to different frequency ranges, each of which has distinct physical properties derived from its wave lengths, magnetic and electrical fields.  Each physical property may affect health in a different way.

The technological advances in telecommunications over the past few decades, have led to increased exposure of the public to non-ionizing radiation. The increasing exposure has raised concern regarding the potential effects of non-ionizing radiation on health.

Numerous studies have examined the effect of non-ionizing radiation on health, and the mechanisms through which it may affect body cells.  The studies examined the effects of various frequencies of non-ionizing radiation, from those of electrical grids (extremely low electromagnetic frequency - ELF) through to microwaves  (ultra-high frequency - UHF).

The best known proven effect of non-ionizing radiation is heating of tissues, observed mainly within the radiofrequency range.  However, heating is minimal in most devices emitting radiofrequency radiation; therefore it does not constitute a significant risk.

The main public concern regarding potential health risks of non-ionizing radiation focuses on the possibility that non-ionizing radiation has non-thermal effects (i.e., effects which are not directly related to heating).

 

 

 

Humans have always been exposed to natural sources of non-ionizing radiation.  However, because of technological advances, and in particular the development of many new modes of communication since the mid-1990s, this type of exposure and its sources have increased significantly.  At the same time, concern was raised over the potential effect of non-ionizing radiation on human health. Consequently, comprehensive research is being carried out to examine the safety of devices that emit non-ionizing radiation.

 

What is the potential biological effect of non-ionizing radiation?

'Biological effect' is defined as a physiological, biochemical or behavioral change taking place in a living organism, tissue or cell.  A biological effect is recognized when a change in a biological system can be measured following some type of stimulation.  A biological effect does not necessarily imply a biological hazard or a health effect, because not every change is harmful.  Moreover, even if there is an effect on health, it may be temporary and reversible and not lead to biological damage. A biological effect becomes a biological hazard only when it causes detectable damage to the health of an individual or its offspring.

 

It should be noted that the biological effect may affect its target directly (for example, damage to the genetic material, DNA, may trigger a cancerous disease), or indirectly (e.g. through molecules that lead to chemical chain reactions which may damage the cell).

 

Non-ionizing radiation may be classified according to different frequency ranges each of which has distinct physical properties, according to its wave lengths, magnetic and electric fields.  Each physical property may have a different effect on health.  Radiation intensity may also have an impact on the biological outcome.  In addition, the effect of non-ionizing radiation may differ according to different properties of the body, such as anatomic build, weight, proportion of water, tissue composition, etc. For instance, a certain exposure may have a different effect on adults compared to children.  

 

Continuous exposure to any factor is generally considered to have a different effect on health than acute exposure.  Also, higher intensities of exposure generally have a stronger effect than low doses (e.g. heavy smoking has a different effect compared to occasional or light smoking).

 

The health effects of a certain type of exposure may be acute, occurring shortly following the exposure, or chronic, appearing some time later. For example, influenza develops a short while (a few days) after exposure to a virus, while cancer usually appears only years after exposure to the harmful factor (e.g. smoking).

 

There is much uncertainty regarding the effects of exposure to non-ionizing radiation on the human body and this is a hotly-debated subject among scientists today.

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