Yes the Children are more exposed to radio-frequency energy from mobile telephones than adults
dinsdag, 07 juli 2015 - Categorie: Onderzoeken
Browse Early Access Articles > Access, IEEE ...> Volume:PP Issue:99
Our reports of published research in several of the peer-reviewed journal articles in 1996, 2002 and 2004 have generated a lot of controversy over the last two decades including the most recent publication by Foster and Chou 1. In this paper we present arguments based on Physics that the main reason for higher exposure of children (also women and men with smaller heads and likely thinner pinnae) to radiofrequency energy from mobile phones is the closer placement of the cell phone radiation source by several millimeters to the tissues of the head, e.g. the brain. Using heterogeneous anatomically-derived shaped models of the head, we have previously reported that the exposure increases by a compounding rate of 10-15% for every single millimeter of closer location of the radiating antenna. This is similar to the report of “~20% increase for every millimeter” in the Foster and Chou’s paper 1 from their Equation 1 even though their simplistic Equation 1 is valid only for a homogenous tissue slab of infinite size and the radiation source that is a wire dipole rather than a mobile telephone. Both of their assumptions for Eq. 1 are obviously not applicable for human exposures to mobile telephones. Actually the physical reason for such a rapid drop off of coupled energy is that the radiofrequency electromagnetic fields close to a radiating source in the so-called “near-field” region reduce in strength very rapidly with every millimeter of distance; even faster than in the “far-field region” where the EM fields reduce inversely with the square of the distance from the source.
... we will present logical arguments based on easy-to-understand physical concepts that led to the conclusions presented in our papers 2-6 that children, women, and people with smaller heads with thinner pinnae will absorb more RF energy as compared to adult males with larger heads and thicker pinnae.
While Foster and Chou mention some of our published papers 2, 3, 6 they do not mention our other papers 4, 5 that address the important role of reduced distance of the radiofrequency (RF) radiating source of the mobile telephone for individuals with thinner pinnae in drastically increasing the SAR measure of RF absorption by 10-15% for every single millimeter of closer placement of the cell phone source of radio frequency radiation for such individuals.
... the main reason or such a drastic reduction of SAR is that the electromagnetic fields of an antenna drop off very rapidly in the so-called “near-field” region of the antenna faster even than in the “farfield” where the fields drop off as the square of the distance from the source.
... it has been reported that the dielectric properties of the various tissues are substantially higher (by 50% or more) for younger rats compared to adult rats. The authors Peyman et al. 7, 8 hypothesize that the decrease in the dielectric properties with age may be due to changes in water and organic contents of the tissues. Even though the corresponding data are not available for the human tissues, the implications for the assessment of exposure of children may be quite significant.
... Based on these studies we report in 5 that a model with thinner pinna of 6 mm thickness gives peak 1-g SAR that is up to 2.5 times higher at 1900 MHz and up to 1.7 times higher at 835 MHz as compared to the same model with thicker pinna of thickness 20 mm.
Since the main reason why children, women, and people with thinner pinnae and skulls absorb more radiofrequency energy is because of the placement of the cell phone radiating source closer to the brain (increasing by 10-15% for every additional millimeter of reduced spacing, determined by using planar, spherical and head-shaped models 2, 5), it is very hard to understand why the FCC allows the use of a large SAM model of dimensions derived from the 90th percentile head size of the U.S. Military recruits for psSAR peak spatial absorption ratecompliance testing against safety guidelines. Furthermore, the FCC-accepted SAM model has a tapered smooth plastic spacer instead of actual tissue pinna which can artificially separate the radiofrequency radiation source of the mobile phone by up to 10 millimeters at some locations resulting in an underestimation of both 1- and 10-g psSAR for male heads and for children and women by two or more times 5. In closing, it is fortuitous that several authors worldwide have now validated our original findings that children, women, and individuals with smaller heads absorb more radiofrequency energy from mobile telephones ....
Om Gandhi, Professor in the Department of Electrical & Computer Engineering at the University of Utah, has published over 200 journal articles on electromagnetic dosimetry, microwave tubes, and solid-state devices. He edited the book Biological Effects and Medical Applications of Electromagnetic Energy (Englewood Cliffs, NJ: Prentice-Hall, 1990), and coedited the book Electromagnetic Biointeraction (New York: Plenum, 1989).
Dr. Gandhi was elected a Fellow of the American Institute for Medical and Biological Engineering in 1997. He has been President of the Bioelectromagnetics Society (1992–1993), Cochairman of IEEE SCC 28.IV Subcommittee on the RF Safety Standards (1988–1997), and Chairman of the IEEE Committee on Man and Radiation (COMAR) 1980–1982. He received the d’Arsonval Medal of the Bioelectromagnetics Society for pioneering contributions to the field of bioelectromagnetics in 1995, the Microwave Pioneer Award of the IEEE-Microwave Theory and Techniques Society in 2001, and the State of Utah Governor’s Medal for Science and Technology in 2002.
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