Human exposure by mobile phones in enclosed areas

Abstract

Human exposure by mobile phones in enclosed areas such as train carriages, elevators, and cars is considered. Equivalent power density and whole body specific absorption rate (SAR) are estimated by applying multimode resonant cavity theory and a straight forward worst case approach. The results show that exceeding the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines due to simultaneous use of several mobile phones in enclosed areas is highly improbable.

A review of mobile phone usage in enclosed areas and RF safety guideline

“…Concerning the whole-body average SAR, it is established in [6,12] that for single passenger using mobile in elevator will not be exceeded. This argument can also be established from theoretical approach of [14,15]. For the spatial 10-g SAR, while the use of dipole antenna shows that if it is placed close enough to the spherical phantom may results in SAR exceeding the basic restriction [18], we found out that even when used in a touch position, the SAR in a phantom produced by a commercial phone when used near the wall is very small [24].…”

“…Most researchers have preferred to use completely covered structures to simulate a worst-case condition [3,[12][13][14][15]. However, we have shown in [6] that a small wall at the top of the elevator does not affect the conservativeness of the results obtained.…”

“…Researchers in [3,[13][14][15] used theoretical approach in their investigation. This method has advantages over the numerical investigation such as its simplicity and short time required to obtain solutions.…”

“…3 A good example to compare theoretical and numerical methods is when 9 passengers are in a completely covered elevator with one non-user passenger at the center surrounded with 8 phone users. If we use theory according to equation (5) in [14], assuming that maximum power from mobile phone is 0.25 W, the SAR of the non-user passenger obtained is 17 mW/Kg. The numerical result obtained by FDTD method is 30 mW/kg [17].…”

Passive Exposure to Mobile Phones: Enhancement of Intensity by Reflection

“…Because the peak exposure level is crucial in considering electro-medical interference, interference to airplanes, and biological effects on human beings, we also need to consider the possible peak exposure level, or hot spots, for the worst-case estimation. Thus, risk assessments based only on average exposure [23][24][25] are inappropriate 26) .…”