Exposures of children in Canada to 60-Hz magnetic and electric fields

Objectives This study sought to characterize personal exposures of Canadian children to 60-Hz magnetic and electric fields and explain the variability . Methods Altogether 382 Canadian children up to 15 years of age wore meters recording 60-Hz electric and magnetic fields over 2 days. Meter location wa s noted. Thereafter, meters measured fields in the center of the children's bedrooms for 24 hours. Personal exposures were calculated for home, school or day care, outside the home, bedroom at night, and all categories combin ed (total). Results The arithmetic mean (AM) was 0.121 mu T [geometric mean (GM): 0.085 mu T), range 0.01-0.8 mu T] for total magnetic fields. Fifteen percent of the total exposures exceeded 0.2 mu T The AM of the total electric fields w as 14.4 (GM 12.3, range 0.82-64.7) V/m. By location category, the highest a nd lowest magnetic fields occurred at home during the day (0.142 mu T) and during the night (0.112 mu T), respectively. Measurements during sleep prov ided the highest correlation with total magnetic field exposure. Province o f measurement explained 14.7% of the variation in the logarithms of total m agnetic fields, and season accounted for an additional 1.5%. Conclusions This study has identified differences in children's magnetic fi eld exposures between provinces. Measurements at night provided the best su rrogate for predicting total magnetic field exposure, followed by at- home exposure and 24-hour bedroom measurements. Electrical heating and air condi tioning, wiring type, and type of housing appear to be promising indicators of magnetic field levels.