Chauvin S, Gibergues ML, Wüthrich G, Picard D, Desreumaux JP, Bouillet JC. Occupational exposure to ambient electromagnetic fields of technical operational personnel working for a mobile telephone operator. Radiat Prot Dosimetry. Ahead of print. Sep 15, 2009.
Beginning in 1988, several committees have established exposure thresholds for electromagnetic fields (EMF), both for the general population and occupationally exposed workers. In 2005, the IEEE produced limits for the frequency spectrum used for wireless communication, from 28 to 61 Vm-1 for the general public and from 61 to 174 Vm-1 for workers. For technical operational personnel working for mobile telephone operators, potential exposure to EMF due to work periods close to transmitters will be interspersed with non-exposed periods in offices or in travel. This needs to be considered when trying to get a realistic picture of occupational exposure to EMF.
The purpose of this study was to test whether technical operational personnel had an exposure profile that could be distinguished from that of other workers.
Technical operational personnel were 23 mobile phone base station workers from the Rhône-Alpes region of France. Other workers were 22 adults from the Île-de-France whose work did not require them to be near base stations. For 3 working days, two exposimeters, each designed to capture different field intensities, were worn by each subject. Measurements were made from November 2006 to January 2007 for technical operational personnel and from August 2006 to October 2006 for the other workers. Both exposimeters were worn in a cloth bag slug over each subject’s shoulders. The exposimeters were vertically positioned in the bag with their front panels facing outward. A validation study by the authors confirmed that although their method of measurement slightly underestimated the measurements made by a free-standing exposimeter not in a cloth bag, this would not bias the results since the same method was used for all subjects.
Based on exposure patterns, the authors tried to identify the following subgroups among other workers: place of residence (Parisians, inner suburban, rural area), type of work (manual work, office work), and transport to work (car, train, metro, bus). Only 3 subjects had a consistent exposure pattern that could be distinguished from the rest of the group, but this did not correlate with any pre-defined subgroup. For technical operational personnel, the authors attempted to identify subgroups based on percentage of time in cars (≥36 vs. <36), percentage of time working on technical equipment (≥37 vs. <37), and percentage of time spent stationary/on standby (≥22 vs. <22). None of the technical operational personnel had a consistent exposure pattern that correlated with any subgroup. When both technical operational personnel and other workers were considered concurrently, the distribution of the exposure data was somewhat suggestive of 2 groups, but this did not correspond to the technical operational personnel and other workers groups.
Interpretation and Limitations
This study is the first to use the same methods to measure exposure among occupationally exposed and non-exposed workers. For other workers, the average exposure levels were very low (<0.13 Vm-1 45% of the time), which is compatible with previous research. Similarly, the average exposure for technical operational personnel was <0.13 Vm-1 55% of the time. The main limitation of this study is the small number of subjects, especially technical operational personnel, who might not be a good representation of the group as a whole.
This study does not suggest that technical operator personnel have a unique exposure pattern compared to that of other workers.