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(Database last updated on Mar 27, 2024)
| ID Number | 1083 | |
| Study Type | Engineering & Physics | |
| Model | 835, 1900 MHz (CW, GSM, CDMA) exposure and modeling of SAR distribution and surface heating using FDTD and vascularized models (including child vs. adult) | |
| Details | Modeling was used to predict temperature rise in humans due to RF exposure from mobile phones. Using exposure at 835 MHz and 1900 MHz, the authors report temperature elevations of up to 4.5 degrees (final temperature 39 degrees) in the pinna of the ear from the use of a mobile telephone (due to warming by the electronic circuitry), while temperature increases for internal tissues (brain and eye) are < 0.1 C0.2 C. For occupational exposures of 8 W/kg for any 1 g, or 10 W/kg for any 10 g of tissue (IEEE and ICNIRP safety guidelines), predicted temperature elevations for exposed parts of the brain would be up to 0.5 C. Similar temperature increases were also calculated for arterial blood temperature. Other studies look at currents and tissue absorption due to exposure at various frequencies. AUTHORS' ABSTRACT: Gandhi et al. 2011 (IEEE #5117):The existing cell phone certification process uses a plastic model of the head called the Specific Anthropomorphic Mannequin (SAM), representing the top 10% of U.S. military recruits in 1989 and greatly underestimating the Specific Absorption Rate (SAR) for typical mobile phone users, especially children. A superior computer simulation certification process has been approved by the Federal Communications Commission (FCC) but is not employed to certify cell phones. In the United States, the FCC determines maximum allowed exposures. Many countries, especially European Union members, use the guidelines of International Commission on Non-Ionizing Radiation Protection (ICNIRP), a non governmental agency. Radiofrequency (RF) exposure to a head smaller than SAM will absorb a relatively higher SAR. Also, SAM uses a fluid having the average electrical properties of the head that cannot indicate differential absorption of specific brain tissue, nor absorption in children or smaller adults. The SAR for a 10-year old is up to 153% higher than the SAR for the SAM model. When electrical properties are considered, a childs heads absorption can be over two times greater, and absorption of the skulls bone marrow can be ten times greater than adults. Therefore, a new certification process is needed that incorporates different modes of use, head sizes, and tissue properties. Anatomically based models should be employed in revising safety standards for these ubiquitous modern devices and standards should be set by accountable, independent groups. AUTHORS' ABSTRACT: Kang and Gandhi 2002 (IEEE #6090): Increasingly, mobile telephones are becoming pocket-sized and are being left in the shirt pocket with a connection to the ear for hands-free operation. We have considered an anatomic model of the chest and a planar phantom recommended by US FCC to compare the peak 1 and 10 g SARs for four typical cellular telephones, two each at 835 and 1900 MHz. An agreement within +/- 10% is obtained between calculated and experimental 1 and 10 g SARs for various separations (2-8 mm) from the planar phantom used to represent different thicknesses of the clothing both for the antenna away from or turned back towards the body. Because of the closer placement of the antennas relative to the body, the peak 1 and 10 g SARs are considerably higher (by a factor of 2-7) for pocket-mounted telephones as compared to the SARs obtained using a 6 mm thick plastic ear head model--a procedure presently accepted both in the US and Europe. This implies that a telephone tested for SAR compliance against the model of the head may be severely out of compliance if it were placed in the shirt pocket. Gandhi 2015 (IEEE #6112): 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. 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 from their (1) even though their simplistic (1) is valid only for a homogenous tissue slab of in nite size and the radiation source that is a wire dipole rather than a mobile telephone. Both of their assumptions for (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 elds close to a radiating source in the so-called near- eld region reduce in strength very rapidly with every millimeter of distance, even faster than in the far- eld region, where the electromagnetic elds reduce inversely with the square of the distance from the source. |
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| Findings | Effects | |
| Status | Completed With Publication | |
| Principal Investigator | University of Utah, USA | |
| Funding Agency | Private/Instit. | |
| Country | UNITED STATES | |
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