There is currently a high level of concern in many countries that exposure to radiowaves from mobile phone base stations may be hazardous to health. When investigating such suggested risks, epidemiologists need to define an exposure metric that can reliably discriminate between exposed and unexposed groups of people. We conducted a feasibility study to investigate if either short-term measurements of electric field strength, calculations of electric field strength, or distance from nearby mobile phone base stations could be used to develop a metric reflecting an individual's exposure to radiowaves. With electric field strengths in the range of 0.012-0.343 V/m, radiowaves from mobile phone base stations were found to give a material contribution to total exposure; however, stronger signals were frequently measured from other sources such as broadcast radio and television transmitters. Theoretical considerations and the measurements made during this work demonstrated that studies at the population level on suggested adverse effects of radiowaves from mobile phone base stations are not feasible since no valid metric for estimating historical exposures is currently available. The pace of radio infrastructure development is also such that today's measurements are unlikely to be good proxies for either past or future exposures. The complex propagation characteristics affecting the beams from base station antennas include shielding effects and multiple reflections from house walls and other buildings. These factors, combined with the presence of other environmental sources of radiowaves, cause distance from a base station to be a poor proxy for exposure to radiowaves indoors. It may be possible to adapt computer models developed by network providers to predict network coverage for epidemiological purposes; however, this has yet to be investigated. Furthermore, there is little evidence that presently justifies epidemiological studies being restricted to adverse effects of radiowaves from mobile phone base stations while neglecting radiowaves at other frequencies produced by different transmitters.
|Number of pages||6|
|Journal||Journal of Exposure Analysis and Environmental Epidemiology|
|Publication status||Published - 2000|
Bibliographical noteFunding Information:
This article was written on behalf of the German study group on tum ours of the head, neck and brain ( Dr. Gabriele Berg, Dr. Maria Blettner, Dr. Jörg Michaelis, Klaus Schlaefer, Dr. Brigitte Schlehofer, and Dr. Jürgen Wahren-dorf). The authors like to thank Dr. Volker Hombach (T-Nova) for comments on the technical part of this manuscript and Josef Opitz (Regulierungsbehörde für Telekom m uni-kation und Post ) for conducting the measurements in Germany. The German feasibility study was funded by the Environment Ministry of Baden-Württemberg, by the Verum foundation and by DeTeMobil.
- Base stations
- Electromagnetic fields
- Epidemiological methods
- Exposure assessment
- Mobile phones