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RF Radiation Safety Limits

Radiofrequency radiation is a non-ionizing form of energy transfer via electric and magnetic fields. Although it is not as biologically hazardous as the ionizing radiation emitted from radioactive sources, exposure to large doses of RF radiation can produce thermal effects in biological tissues.

  1. Harmful Effects of RF Radiation

    • "RF radiation" is the term used to describe a field of low-energy photonic activity, like the field that is produced in a microwave appliance. Just as when food is exposed to a microwave field the resulting excitations of the atoms that comprise the food produce a thermal heating effect, so also large doses of RF radiation can literally "cook" human tissues.

    Sources of RF Radiation

    • Radiofrequency energy is the primary component of telecommunications. Large-scale sources of RF radiation include transmitting antennas for television broadcasts, radio communications of all types, satellite links, and mobile phone communications towers including cellular and PCS services.

    RF Safety Limits

    • The exposure threshold at which harmful biological effects are known to occur is a whole body specific absorption rate of four watts per kilogram for most frequencies. This means that biological tissues can withstand a power density of four watts per kilogram of mass before a thermal heating effect is detectable. However, whole body absorption is frequency-dependent, and therefore exposure limits vary with different frequencies--most notably in the range of 30 to 300 MHz, where biological tissues absorb RF efficiently.

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