Posted By Neil Pearson Hi Everyone. Someone has got hold of a Gauss meter and measured their local EMF field at 6mG. They say the safe level is 2mG. The NRPB site talks about EMF field strength in volts per metre. I don't have conversion tables with me today. Can someone help me out with definitive safe levels of EMF field strength before I get the levels checked?

Posted By Neil Pearson Thanks Rakesh, but that talks about different units again!

Posted By Jane Blunt Dear Neil Gauss is a unit used to measure magnetic field (although these days the preferred unit is Tesla). Magnetic field is also measured in Amps per metre. 1 Tesla is 10 000 Gauss. Therefore the measurement you give - 6 mG is equivalent to less than a microtesla. If this is correct, it is not untypical of the levels measured by NRPB at a number of locations. Volts per metre is a measure of electric field. You don't say what the source of your field is, which is an important consideration. Whether it is safe or not depends on a number of things, not least of which is the frequency. Stationary magnetic fields have a suggested limit of 200 mT (2000 Gauss) averaged over 24 hours. You can get this kind of field from an ordinary strong bar magnet. The maximum values are 2T to 5T, depending on the part of the body, but unless you work in a place with superconducting magnets you are never likely to run across a field this high. There are other considerations, however, depending on the source of your field. If the field is coming from a magnet, at fields above about 3 mT (30 Gauss) you may have to worry about loose ferromagnetic objects. If there is a magnet nearby, things can get drawn into it (there was a fatality in a hospital where a gas cylinder got drawn into a body scanner, striking the young patient). Those with pacemakers MAY be affected by fields of order 0.5 mT (5 Gauss) (stationary) or 20 microtesla (200 mG) (time-varying). Also, some floppy discs can be wrecked by stray fields of several mT. There is a paper on the subject of magnetic fields, which also tells us of some beneficial effects (speeding the healing processes): Static and low-frequency magnetic field effects: health risks and therapies. Robert K Adair, Rep. Prog Phys 63 (2000) pages 415-454. With all the figures above, apologies if I have got any of the conversion factors wrong!! The jury is still out on the health effects. Regards Jane

Posted By John Murgatroyd Are you talking about effects from alternating or static magnetic fields ? non-ionising radiation would indicate electromagnetic fields, such as those from radio transmitters. In any case, while the subject has been raised, how about the effect of NO magnetic field...such as the one that surrounds the planet ? In case you didn't know, it has dropped in field strength by about 10% in the last 150 years, which raises the spectre of it ceasing altogether in the near future....in which case the effects of minor magnetic fields on health will become of an urgent nature. Oh, and cars with the accumulator at the rear and large diameter cables taking the current to the front frequently exceed the recommended levels....but you're still several million times more likely to be killed in a crash than from any possible health effects of magnetic fields. http://www.fmrib.ox.ac.u...hapter_2/section2_7.html http://www.niehs.nih.gov/emfrapid/home.htm http://www.rare-earth-ma...ic_fields_and_health.htm