Assessment and grouping of occupational magnetic field exposure in five electric utility companies.
Kromhout-H; Loomis-DP; Mihlan-GJ; Peipins-LA; Kleckner-RC; Iriye-R; Savitz-DA
Scand J Work, Environ & Health 1995 Feb; 21(1):43-50
Magnetic field exposures were assessed among electric utility workers at five electric utility companies. The workers were randomly selected from 28 job categories which involved exposures to 60 hertz magnetic fields. The average exposures ranged from 0.11 and 1.50 microteslas (microT). Magnetic field exposures for each worker were measured by a personal magnetic field exposure meter. Data were analyzed by a random effects analysis of variance model. Different groupings were made on the basis of estimated exposure level, occupational category, company, and possible combinations of the variables and compared. Differences in exposure levels among the five companies were small, with the more urban companies having slightly higher exposure levels. The day to day component of variance was higher than the within and between group components of variance. The final job exposure matrix consisted of five groups with average exposure levels ranging from 0.12 to 1.27microT. The authors conclude that the job exposure matrix used in this study effectively incorporated the differences in exposure within occupational categories between companies and provided an objective and statistically based method for estimating cumulative magnetic field exposure. They note that whether the optimal grouping of magnetic field exposure will yield groups of workers with distinctly different levels of cumulative exposure will depend on the distribution of person years spent in the different occupational categories.
NIOSH-Author; Electromagnetic-fields; Epidemiology; Electrical-workers; Magnetic-fields; Exposure-levels; Occupational-exposure; Risk-analysis;
Author Keywords: exposure assessment; magnetic field exposure levels; misclassification; occupational exposure. precision; resolution
Dr Hans Kromhout, Department of Air Quality, Wageningen Agricultural University, PO Box 8129, 6700 EV Wageningen, The Netherlands
Scandinavian Journal of Work, Environment and Health