Bioelectromagnetics Journal, Cindy Sage, Olle Johansson and S. Amy Sage

Abstract - Initial tests indicate that personal and occupational use of personal digital assistants (PDAs or palm-held wireless units) produce high intensity bursts of extremely-low frequency electromagnetic fields (ELF-EMF).  These emissions could result in comparatively high ELF-EMF exposure in persons that carry a PDA close to the body (i.e., in a pocket or on a belt); or held to the head for cell phone conversations. ELF-EMF emissions of 10+ µT were recorded on PDAs during normal office use over a 24-hour test period.  Results of ELF-EMF measurements show that email transmit and receive functions produce rapid, short-duration ELF-EMF spikes in the 2 µT to 10 µT range, each lasting several seconds to over a minute apparently depending on file download size.  Some units produced spikes as high as 30 to 60 µT during email activities.  Cell phone activity on PDAs produced continuously elevated ELF-EMF readings in the 0.5 µT to 1 µT range, as opposed to the rapid spiking pattern for email receipt and transmission.   Switching the PDA unit from “OFF” to “ON” position resulted in single ELF-EMF pulses of over 90 µT on two units.  Email downloads into the PDA can occur randomly throughout the day and night when the unit is “ON”; thus the user who wears the PDA may be receiving high-intensity ELF-EMF pulses throughout the day and night.  The frequency of email traffic on the PDA, and the power switching unit (battery unit) may affect the frequency and intensity of ELF-EMF emissions.