Improved Magnetic Field Exposure Assessment

摘要

An attempt was made to improve the characterization of magnetic field exposure inthe workplace, and to develop new ways in which exposure variability may be understood for epidemiologic investigations. As part of a case/control study of brain cancer at a large automobile transmission facility, a strategy was developed to use two types of instruments to measure personal exposure to power frequency magnetic fields. The rate of falloff of magnetic field strength with distance was rapid, but the impact of this on exposure variability at individual work stations was less than expected. Correlations among exposure indices suggested that they do not rise and fall together. The authors conclude that further work in the area is needed both to identify appropriate biological mechanisms and their corresponding indices, and to better understand the bias which may arise from misspecified exposure indices in an epidemiologic analysis. Comparisons between exposures at the auto facility with those measured in the electric utility and electronic industries suggested that the differences only lie among the most highly exposed sectors of electrical work.