Here is an interesting documentary on the effects of EMF radiation in our environment.  If you have a spare hour and a half, this is well worth watching, and quite frightening. Note they talk about Schumann resonance here; you may know also that Blushield does a whole lot more than just reproduce the Schumann resonance, and they are talking about one aspect of the Earth's magnetic field.

Check out all our Blushield devices here, from stationary home to portable units.