Measurement of the individual exposure to 50 and 16 2/3 Hz magnetic fields within the Bavarian population

Abstract

This study investigates the individual magnetic field exposures at 16 2/3 and 50 Hz of 1952 people, selected from the Bavarian population. Personal flux density meters (“Field Watcher FW2A”) were worn by the participants for 24 h. Every second, the flux density was recorded for both frequencies and for the three spatial axes (dynamic range per axis: several nT up to 100 μT at 50 Hz, 150 μT at 16 2/3 Hz). For 50 Hz fields, the mean of the 1,952 individual means was 0.101 μT and that of the individual medians was 0.047 μT. High level exposures occurred mainly during working hours. Only 2.4% of the subjects showed individual medians higher than 0.2 μT. About 53% of all volunteers were working on the day of recording. Levels for craftsmen (n = 148; mean individual mean: 0.166 μT) were generally higher than those for office workers (n = 624; mean individual mean: 0.107 μT). Flux densities exceeding 100 μT at 50 Hz were measured in 31 persons. The total time with such extreme exposures amounts to nearly 21 min, less than 0.001% of the total time for all measurements (5.3 years). To our knowledge, this is the first exposure study where 16 2/3 Hz magnetic fields (caused by electrified railways) have additionally been monitored over 24 h. For persons living next to railway lines, the mean individual mean (0.156 μT) and mean individual median (0.102 μT) were calculated. Over all, the mean exposures are only 0.1% of the magnetic flux density limit for 50 Hz (100 μT) and about 0.05% of the limit (300 μT) for 16 2/3 Hz recommended by the International Commission on Non‐Ionizing Radiation Protection. Bioelectromagnetics 22:323–332, 2001.