I'm thinking the wavelength of the EMF emitted from the plasma tube will have a factor depending on the grounding cloth. Depending on the spacing of the shielding in the ground cloth will determine it's shielding effect. Since the mat is probably designed to mitigate the effect of EM waves coming from mobile phones, wireless internet, wireless phones, etc I assume it will also effectively reduce the emf from the plasma tube if the mat was held vertically between you and the plasma tube. Having the mat in the horizontal plane I suspect it would have little effect if any at all.
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