Inyang, I. Benke, G. McKenzie, R. and Abramson, M. Use of hardware modified phones for exposure assessment in health studies in Australia: verification of compliance with standards. Australas Phys Eng Sci Med. 2009 Jun; 32(2):62-7.
Epidemiological studies of health effects of radiofrequency fields (RF) exposure from mobile phones (MPs) produce inconsistent, non-reproducible and sometimes contradictory results. Difficulties in exposure assessment and dosimetry are considered a major contributor to these discrepancies. Information from questionnaires commonly used for exposure assessment is not very accurate. Subscription records also have limitations. The authors present a device that may influence exposure assessment in population-based mobile phone and health studies.
The authors’ objective in this article was to describe the calibration of hardware modified phones (HMPs) for exposure assessment and dosimetry and to compare emissions from the HPMs with the Australian and ICNIRP standards for all orientations of use.
The hardware modified phone was placed on human head phantom, and SAR measurements were taken by a robotic SAR measurement system DASY3 at 900 and 1800 MHz frequency bands on both sides of the phantom. The authors anticipated that adolescents might use phones differently from adults, thus, tilts, rotations and their combinations were varied to simulate not only conventional, but also worst case scenarios of mobile phone placement by adolescents.
The results indicate that tilts influence SAR more than rotations. At 900 MHz, the maximum SAR obtained with hardware modified phones in the touch position was 0.9 W/kg and at 30 degrees tilt - 0.4 W/kg. At 1800 MHz, these values were 1.1 W/kg and 1.3 W/kg for the touch position and 30 degree tilt, respectively. At 900 MHz the SAR decreased with increasing tilt, while at 1800 MHz the SAR increased with increasing tilt. At 1800 MHz the mean SAR at 30 degrees tilt was 0.22 W/kg higher than at 0 degrees, but at 900 MHz the mean SAR at 30 degrees tilt was 0.60 W/kg lower than at 0 degrees. Under the worst case scenario (30 degrees tilt with + or – 60 degrees rotation) SAR was 1.31 W/kg at 1800 MHz, which is below the ICNIRP limit of 2 W/kg. The SAR was slightly (non-significantly) greater when the phone was used on the left side of the phantom compared to the right side, especially at 1800 MHz.
Interpretation and Conclusion
Even under the worst case scenario of mobile phone placement, the SAR from the hardware modified phones was below the ICNIRP standard. Thus, the authors have concluded that these modified phones are compliant with ICNIRP and Australian standards. More widespread use of hardware modified phones will improve exposure assessment in studies of health effects of radiofrequency field emitted from mobile phones.