Why Low-Frequency EMF Safety Would Benefit From Peak-Based Limits Instead of RMS Values

Current low-frequency EMF exposure limits are based on RMS values. However, the hazard at low frequencies, neural and muscular stimulation is driven by instantaneous peak values. Because action potentials follow an all-or-nothing threshold, even a single suprathreshold cycle can trigger excitation, whereas long-term RMS averages can be arbitrarily reduced by inserting pauses into signals. Pulsed or bursty fields-such as those emitted by certain deactivators used in electronic article surveillance-may comply with RMS-based limits despite containing peaks capable of exceeding physiological thresholds. Reformulating both basic restrictions and reference levels in terms of peak values would align exposure limits with neurophysiological mechanisms and provide clearer guidance for ensuring safety. As ICNIRP revises its 2010 low-frequency guidelines, this is an opportune moment to adopt peak-based limits and better protect workers and the general public.