Bluetooth and Health: The Radiation Issues |
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It is a matter of concern to some that the carrier waves used by Bluetooth inhabit the same band as that of microwave ovens. As being cooked inside a microwave oven would produce deleterious effects in most, should we be worried about standing in the path of a plethora of Bluetooth devices? Fortunately, the transmitting power is far too weak to result in perceptible effects in humans. Moreover, the radiation is not concentrated in a single beam; rather, it is randomly dispersed in all directions. The penetration depth of a device working in the 2.4Ghz frequency range is about 1.5cm - nothing more than a superficial absorption. The principal absorption mechanism is field-induced rotation of polar molecules (H2O for example) which generates heat through molecular 'friction'. It is however important to note that 2450Mhz is not a resonance frequency of water. Heating by means of radio frequencies is possible over a broad frequency range. Microwave ovens exploit this phenomenon by using very high power levels (up to one million times greater than the power output of Bluetooth transmitters). So does exposure to Bluetooth radio frequency emission result in heating of the body? No, definitely not. The power output is far too low to result in any tangible increase. By way of comparison, the maximum increase in brain temperature through use of a mobile is 0.1ºC. However, this assurance is not the same as saying that prolonged exposure to the Bluetooth RF will not produce negative effects in people. If Bluetooth becomes a truly ubiquitous technology, those of us living in cities and working in offices will presumably be exposed 24/7. This may not be a good thing. Long exposure to strong fields results in some individuals becoming hypersensitive so that after a few years, they can no longer tolerate being near such fields. Bluetooth fits into a general development pattern where antennas for GSM transmission and other sources of electromagnetic radiation become more and more prevalent in our cities. The future will show whether this is a healthy development. |