Induced foot-currents in humans exposed to VHF radio-frequency EM fields

Tofani, Santi; d'Amore, G.; Fiandino, G.; Benedetto, A.; Gandhi, O.P.; Chen, J.Y.

doi:10.1109/15.350247

Cited by 13 publications

(4 citation statements)

References 7 publications

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“…For frequencies >70 MHz, coupling normalized to frequency [ I ( E - h 2 - f ) −1 ] is about 18% of its value for frequencies between 100 kHz and 30 MHz (based on Fig. 3, data not shown) [(Guy (unpublished - see footnote 4); Blackwell 1990; Lubinas and Joyner 1992; Tofani et al 1995]. (Between 30–70 MHz, coupling normalized to frequency is 84% of its value at ≤30 MHz, data not shown.)…”

Section: Discussionmentioning

confidence: 99%

“…These included both peer-reviewed journals and reports and communications from various sources. Of these, 18 reported measurement data from human subjects under various E-field exposure conditions spanning from 60 Hz to about 150 MHz (Bracken 1976;Deno 1977;Gronhaug and Busmundrud 1982;Guy and Chou 1982;Gandhi et al 1985Gandhi et al , 1986Hill and Walsh 1985;Allen et al 1988;Blackwell 1990;Joyner 1991, 1992;Olsen and Griner 1993;Tofani et al 1995;Anderson and Joyner 1997;Wilen et al 2001) 3-5 . In 10 references, E-field coupling was modeled using anatomical representations of humans and spanning frequencies from 60 Hz to about 2 GHz (Gandhi et al 1985(Gandhi et al , 1992Dimbylow 1988Dimbylow , 1991Dimbylow , 2002Chen and Gandhi 1989;Jokela et al 1994;Tofani et al 1995;Dawson et al 2000;Findlay and Dimbylow 2008) (two references included both measurements and modeling).…”

Section: Electric Field/short-circuit-current Coupling In Humansmentioning

confidence: 99%

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Aligning Exposure Limits for Contact Currents with Exposure Limits for Electric Fields

Kavet

Tell²

2023

Health Physics

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The Institute for Electrical and Electronic Engineers (IEEE) and the International Commission on Non-ionizing Radiation Protection (ICNIRP) have established limits for exposures to electromagnetic fields across the 0–300 GHz (non-ionizing) spectrum, including limits on contact currents (CC) specified by IEEE for 0–110 MHz (ICNIRP issued a CC “guidance level”). Both sets of limits seek to protect against potentially adverse effects, including aversive electrostimulation at frequencies <100 kHz and excessive heating of tissue at frequencies >100 kHz. For the most part, CC is linked to electric field (E-field) exposures for an ungrounded person contacting a grounded object, with the short-circuit current (ISC) through the contact point (usually the hand) equivalent to the current through the grounded feet of a free-standing person exposed to a vertically polarized E-field. The physical linkage between these two quantities dictates that their respective exposure limits align with one another, which is presently not the case, especially with respect to frequencies from100 kHz to 110 MHz. Here we focus specifically on recommendations for revisions to the IEEE standard, IEEE Std C95.1™-2019 (“IEEE C95.1”), in which the E-field exposure limit (E-field exposure reference levels, ERLs) >100 kHz induces substantially greater currents than the CC ERLs currently prescribed. The most important scenario deserving of attention concerns finger contact through a 1-cm2 cross-sectional interface between the skin and a grounded conductor in which the rate of temperature rise in the presence of an E-field ERL can be rapid enough to cause a burn injury. This rate is highly dependent on the moistness/dryness of the skin at the contact point (i.e., its impedance)—a highly variable value—with temperature increasing more rapidly with increasing dryness (greater contact impedance). The two main remedies to alleviate the possibility of injury in this “touch” scenario are to (a) limit the time of finger contact to 1 s in all cases and (b) revise the E-field ERL between 100 kHz and 30 MHz from a “hockey-stick-shaped” curve vs. frequency to a “ramp” across this frequency range. These measures factored in with the real-world prevalence of potentially hazardous scenarios should afford greater protection against adverse outcomes than is presently the case. IEEE C95.1 also specifies limits for grasp contact (15 cm2 in the palm) and associated wrist heating, plus heating in the ankles from free-standing induction. However, these scenarios are more manageable compared to finger touch due mainly to the comparatively lower rates of tissue heating attributable to the wrist’s and ankle’s relatively greater cross-sectional area. Recommendations for grasp can thus be dealt with separately. Two identified but unaddressed issues in IEEE C95.1 deserving of further attention are first, the circumstance in which a grounded person contacts an ungrounded object situated in an electric field for which there are countless numbers of scenarios that are not am...

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Section: Discussionmentioning

confidence: 99%

Section: Electric Field/short-circuit-current Coupling In Humansmentioning

confidence: 99%

Aligning Exposure Limits for Contact Currents with Exposure Limits for Electric Fields

Kavet

Tell²

2023

Health Physics

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“…To harmonize the MPL in the 30–300 MHz frequency range, experiments should be conducted to research EMF biological effects in conjunction with epidemiological studies. There are few biological studies in this frequency range, and they were mainly focused on short‐term effects—radiofrequency (RF) current intensity in human limbs [Tofani et al, ] or temperature increases [Chen and Gandhi, ]. However, many television, radio broadcasting, and professional communication systems, unlike cellular communication systems and other household RF sources, operate in the meter wavelength frequency range.…”

Section: Introductionmentioning

confidence: 99%

Effects of 171 MHz Low‐Intensity Electromagnetic Field on Glucocorticoid and Mineral Corticoid Activity of the Adrenal Glands of Rats

Perov

Rubtsova

Balzano

2019

Bioelectromagnetics

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A sub-acute electromagnetic field (EMF) biological effect study was carried out on rats exposed in the Transverse ElectroMagnetic exposure chamber at 171 MHz Continuous Wave (CW). The experiments involved three exposure levels (15, 25, and 35 V/m) for 15 days with triplicate parallel sham-exposed controls in each series. All exposure conditions were simulated for the evaluation of the electromagnetic energy distribution and specific absorption rate (SAR) in the rat phantoms. Studies have shown a biphasic biological response depending on time and absorbed electromagnetic energy. Under low SAR, approximately 0.006 W/kg, EMF exposure leads to the stimulation of adrenal gland activity. This process is accompanied by an initial increase of daily excretion of corticosterone and Na + , which is seen as a higher Na + /K + ratio, followed by a decrease of these parameters over time. It is possible that EMF exposure causes a stress response in animals, which is seen as an increased adrenal activity. Bioelectromagnetics. 2019;40:578-587.

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“…In the 1 -90 MHz range the limits established by ICNIRP [1] and IEEE [2] are defined in terms of external electric and magnetic fields, induced currents, current density and specific absorption rate (SAR). Tofani et al reported that some limits are not fully consistent with each other, in particular in 90 -104 MHz range [3]. Although the limits on external electric field were not overpassed, the induced current exceeded the limits, which were the following: 45 mA for uncontrolled environment and 100 mA for controlled environment through one foot between 0.1 MHz and 100 MHz [4].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of currents induced in human body by plane wave exposure at 1–90 MHz

Frère

Alcaras

Lemoine

et al. 2017

2017 11th European Conference on Antennas and Propagation (EUCAP)

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Abstract-In existing exposure standards and guidelines the relationship between dosimetric quantities at a given frequency is not always consistent as some simultaneously applied limits are more restrictive than others, e.g. limits on induced currents compared to those on external electric field or specific absorption rate (SAR). To evaluate the current induced in the human body in 1 -90 MHz range, we propose an equivalent circuit composed of two elements: the first one provides the voltage at human body mid-height and the second one describes the equivalent human body impedance. Then, assuming that the human body is equivalent to an antenna between 1 and 90 MHz, we calculate induced currents at the human body height. Using the relationship between external electric field and voltage at the body mid-height, we calculate the current along the body and suggest updated limits on induced currents more consistent with the external electric field limits.

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Induced foot-currents in humans exposed to VHF radio-frequency EM fields

Cited by 13 publications

References 7 publications

Aligning Exposure Limits for Contact Currents with Exposure Limits for Electric Fields

Aligning Exposure Limits for Contact Currents with Exposure Limits for Electric Fields

Effects of 171 MHz Low‐Intensity Electromagnetic Field on Glucocorticoid and Mineral Corticoid Activity of the Adrenal Glands of Rats

Evaluation of currents induced in human body by plane wave exposure at 1–90 MHz

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