Human exposure to magnetic fields: a comparative assessment of two dosimeters.
Two types of dosimeters for measuring human exposure to 60 Hz magnetic fields were compared. Fifty adults wore the single-axis, wrist model AMEX (average magnetic field exposure system) and the triple axis, hip-pocket or pouch model AMEX-3D meters for 2 days. Ninety-six percent of the tests were accomplished without apparent dosimeter failure. The average root mean square magnetic flux density measurements with the AMEX-3D (mean = 0.10 microT, S.D. = 0.07, range = 0.03-0.31) were significantly higher than with the AMEX meter (mean = 0.07 microT, S.D. 0.05, range = 0.02-0.27 microT) (t test, P < 0.01). There was substantial correlation between the AMEX and the AMEX-3D measurements (Pearson's correlation coefficient = 0.65, P < 0.01) but poor concordance (Intraclass correlation coefficient = -0.25). These results suggest that there is a wide variation in exposure to extremely low frequency magnetic fields in the population. Magnetic field measurements with the AMEX-3D are nearly always higher than with the AMEX dosimeters. Caution is advised when comparing magnetic field measurements made with different types of dosimeters.
Dlugosz
L
L
Department of Epidemiology and Public Health, Yale School of Medicine, New Haven, Connecticut 06510.
Belanger
K
K
Johnson
P
P
Bracken
M B
MB
D000328:Adult; D055590:Electromagnetic Phenomena; D004781:Environmental Exposure; D004867:Equipment Design; D005260:Female; D005373:Film Dosimetry / Q000295:instrumentation*; D006801:Humans; D008280:Magnetics; D008297:Male; D011829:Radiation Dosage