Radiation Protection

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Radiofrequency Radiation

Radiofrequency electromagnetic radiation carries energy and information.

What is radiofrequency radiation?

Radiofrequency (RF) electromagnetic radiation (EMR) is the transfer of energy by radio waves. RF EMR lies in the frequency range between 3 kilohertz (kHz) to 300 gigahertz (GHz). RF EMR is non-ionising radiation, meaning that it has insufficient energy to break chemical bonds or remove electrons (ionisation).

The radiofrequency spectrum - with frequency and sources

What are some sources of radiofrequency radiation?

RF EMR is produced by both natural and artificial sources. Natural sources like the sun, the earth and the ionosphere all emit low level RF fields. Artificial sources of RF EMR are mainly used for telecommunications purposes. Radio and television broadcasting, mobile phones, pagers, cordless phones, police and fire department radios, point-to-point links and satellite communications all produce RF EMR. Other sources of RF fields include microwave ovens, radar, industrial heaters and sealers, and various medical applications.

How is radiofrequency radiation measured?

RF EMR has both electric and magnetic field components. It is often convenient to express the strength of the RF field in terms of each component. For example, the unit "volts per meter" (V/m) is used to measure the electric field strength , and the unit "amperes per meter" (A/m) is used to express the magnetic field strength. Another common way to characterise an RF field is by means of the power density. Power density is defined as power per unit area and is expressed in units of watts per square metre (W/m2) (or milliwatts per square centimetre, mW/cm2, or microwatts per square centimetre, µW/cm2). The quantity used to measure how much RF EMR is actually absorbed by the body is called the Specific Absorption Rate or SAR. The SAR is usually expressed in units of watts per kilogram (W/kg) or milliwatts per gram (mW/g). The measurement of RF fields is described in detail in the Brooks Air Force Bases’s Radiofrequency Radiation Dosimetry Handbook.

How am I exposed to radiofrequency radiation?

Most RF fields found in the environment are due to commercial radio and TV broadcasting, and from telecommunications facilities. RF exposure from telecommunications facilities is generally less than from radio or TV broadcasting. RF sources in the home include microwave ovens, mobile telephones, cordless telephones, wireless computer networks, burglar alarms, and remote controls. Overall, the RF field background level from household appliances is low, and of the order of a few tens of µW/m2. Relatively high levels of exposure to RF fields can occur to workers in the broadcasting, transport and communications industries when they work in close proximity to RF transmitting antennas and radar systems. Some industrial processes that use RF fields to heat materials can also produce high exposure to workers.

What are the health effects of radiofrequency radiation exposure?

Exposure to sufficiently high levels of RF EMR can heat biological tissue and potentially cause tissue damage. The amount of environmental RF EMR routinely encountered by the general public is too low to produce significant heating or increased body temperature. At low levels of exposure to RF EMR (ie field intensities lower than those that would produce measurable heating) the evidence for production of harmful biological effects is ambiguous and unproven. Although there have been studies reporting a range of biological effects at low levels, there has been no indication that such effects might constitute a human health hazard. Some epidemiological studies have shown an association between heavy mobile and cordless phone use and brain cancer (most pronounced for glioma). Limitations of the methodology prevent conclusions of causality being drawn from these observations. The possibility of adverse health effects from the use of mobile phones is described in the ARPANSA fact sheet Mobile Telephones and Health Effects.

How can I protect myself from RF exposure?

In 2002 ARPANSA published the standard: Radiation Protection Standard - Maximum Exposure Levels to Radiofrequency Fields - 3 kHz to 300 GHz. The ARPANSA RF Standard sets limits for human exposure to RF EMR in the frequency range 3 kHz to 300 GHz. The Standard also includes requirements for protection of the general public and the management of risk in occupational exposure, together with additional information on measurement and assessment of compliance.

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