#678: Personal Digital Assistant (PDA) emit ELF magnetic fields
From Cindy Sage, Sage Associates:
Dear friends,
Here is our new paper in the Bioelectromagnetics Journal.
We measured the ELF (the extra-low frequency EMF) from PDAs like Blackberry and Treo units. ELF is produced during switching of the battery inside the PDA. Note that the measurements were given in microtesla (so multiply by 10 to get milligauss).
Since people typically wear them around all day long, this is essentially a measure of body exposure.
Emissions up to 975 milligauss were recorded; during email send and receive functions, the units commonly had spikes of 30 to 60 milligauss. Some busy people we tested had nearly continuous flow of emails during work and even after-work hours.
This would dwarf nearly all other sources of ELF that people are commonly exposed to in daily life.
The only way one might get such high readings on a day-to-day basis would be to hold your head against an electrical subpanel on the wall, unless you have some unusual occupational exposure.
Several measures for prudent avoidance are recommended….using a land line in preference to a PDA for phone calls, keeping the unit off or in “not transmit/receive mode” except to download and send emails, placing the PDA several feet away at your work space or desk, not wearing the PDA in a pocket or on a belt, placing it on the adjacent seat when you drive, and not using it as a cell phone without an earpiece or on speaker (if that is an option).
Obviously children should not use them at all; and caution might be advisable for women who are pregnant since there is some evidence that intermittent exposure to 16 mG and above may be linked to increased risk of miscarriage. Men might take note that ELF magnetic fields have been reported to have adverse effects on semen quality and sperm motility.
The abstract is below – email me if you’d like the full pdf.
Questions cheerfully fielded….
Cindy Sage
Sage Associates
Bioelectromagnetics (2007)
Personal Digital Assistant (PDA) Cell Phone Units Produce Elevated Extremely-Low Frequency Electromagnetic Field Emissions
Cindy Sage,1* Olle Johansson,2 and S. Amy Sage1
1 1396 Danielson Road, Santa Barbara, California
2 The Experimental Dermatology Unit, Department of Neuroscience,
Karolinska Institute, Stockholm, Sweden
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 uT were recorded on PDAs during normal office use over a 24 h test period. Results of ELF-EMF measurements show that email transmit and receive functions produce rapid, short-duration ELF-EMF spikes in the 2 “” 10 uT range, each lasting several seconds to over a minute apparently depending on file download size. Some units produced spikes as high as 30 “” 60 uT during email activities. Cell phone activity on PDAs produced continuously elevated ELF- EMF readings in the 0.5 “” 1 uT 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 uT 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.
Bioelectromagnetics. 2007 Wiley-Liss, Inc.
Key words: wireless communication devices; emissions; extremely-low frequency electro- magnetic fields; precautionary principle
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