Exposure of adults to extremely low frequency magnetic field in France: results of the EXPERS study

Assessing the exposure of adults to magnetic field is a central point in the context of epidemiological studies. The EXPERS study is the first study at national scale in Europe with measurements of personal exposure to extremely low frequency magnetic fields, involving 1046 French adults with 24 h personal measurements. The proportion of adults with a 24 h AM of ≥ 1 μT was 2.1% for all adults and 0.3% for adults for which no alarm clock was identified, as this requirement of the measurement protocol was sometimes not respected. The alarm clocks were the main variable linked to the adults' exposure measurements. The vicinity of the home to a high voltage power line increased the magnetic field exposure. However, only 1.7% of the adults were living close to a 63 to 400 kV overhead line, and only one of them had a personal exposure ≥ 1 μT with an AM of 1.1 μT. The exposure of adults was also correlated with some characteristics of the home and its environment, and some durations of activities, such as the duration of work and the duration in rail transport. The distribution of adults' personal exposure was significantly different from the distribution of exposure during sleep, and from the distribution of exposure assessed from measurements during sleep and work. This highlights the complexity of the exposure assessment in epidemiological studies. (authors)