Levallois P, Gauvin D, Gingras S, St-Laurent J
Direction de la santé publique de Québec, Beauport, Québec, Canada.
Bioelectromagnetics. 1999 Sep;20(6):331-7. doi: 10.1002/(sici)1521-186x(199909)20:6<331::aid-bem1>3.0.co;2-6.
This study compares stationary home measurements with a personal exposure monitor of 60 Hz magnetic fields in a group of 18 people living near a 735 kV 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 meter for 24 h, while a similar meter was left in their home, away from any appliances. For people living away from the line, the impact of residential activities appeared rather weak when considering the average intensity of the field during the awake period (at home): 0.22 microT for personal exposure versus 0.18 microT for stationary measurements (P = 0.09). The impact of residential activities during the awake period was more detectable when using the percentage of time with exposure above 0.78 microT: median 0.4 for personal vs. 0.0 for stationary measurements (P =.01). The temporal variability of the exposure during the awake period was also significantly higher for personal exposure than for stationary measurements. For people living near the line, the intensity of the magnetic field from the line dominated the personal exposure when considering the mean of measurements and the percentage of time 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 usefulness of considering different indexes of exposure when assessing residential exposure to 60 Hz magnetic fields.
本研究比较了居住在735千伏线路附近的18人和居住在远离该线路处的17人的60赫兹磁场的家庭固定测量值与个人暴露监测值。他们大多是白天工作的白领。他们佩戴个人正电子测量仪24小时，同时在其家中放置一个类似的测量仪，远离任何电器。对于居住在远离线路处的人，考虑清醒时段（在家中）磁场的平均强度时，居住活动的影响显得相当微弱：个人暴露为0.22微特斯拉，而固定测量为0.18微特斯拉（P = 0.09）。当使用暴露高于0.78微特斯拉的时间百分比时，清醒时段居住活动的影响更易察觉：个人测量的中位数为0.4，而固定测量为0.0（P = 0.01）。清醒时段个人暴露的时间变异性也显著高于固定测量。对于居住在靠近线路处的人，考虑测量均值和高于阈值的时间百分比时，来自线路的磁场强度主导了个人暴露。然而，清醒时段个人暴露的时间变异性更大。尽管本研究样本量小，存在局限性，但似乎表明在评估住宅对60赫兹磁场的暴露时考虑不同暴露指标是有用的。
