Comparison between personal exposure to 60 Hz magnetic fields and stationary home measurements for people living near and away from a 735 kV power line

This study compares stationary home measurements with a personal exposure m onitor of 60 Hz magnetic fields in a group of 18 people living near a 735 k V line and 17 people living far away from the line. Most of them were white collar workers who worked during the day. They wore a personal Positron me ter for 24 h, while a similar meter was left in their home, away from any a ppliances. For people living away from the line, the impact of residential activities appeared rather weak when considering the average intensity of t he field during the awake period (at home): 0.22 mu T for personal exposure versus 0.18 mu T for stationary measurements (P = 0.09). The impact of res idential activities during the awake period was more detectable when using the percentage of time with exposure above 0.78 mu T: median 0.4 for person al vs. 0.0 for stationary measurements (P = .01). The temporal variability of the exposure during the awake period was also significantly higher for p ersonal exposure than for stationary measurements. For people living near t he line, the intensity of the magnetic field from the line dominated the pe rsonal exposure when considering the mean of measurements and the percentag e of lime above a threshold. However, the temporal variability was greater for the personal exposure during the awake period. Although limited due to its small sample size, the present study seems to demonstrate the usefulnes s of considering different indexes of exposure when assessing residential e xposure to 60 Hz magnetic fields. Bioelectromagnetics 20:331-337, 1999. (C) 1999 Wiley-Liss, Inc.