Systematic Numerical Analysis of Magnetic Field Partial Body Exposure and Comparison With Occupational Exposure Limit Values According to European Directive 2013/35/EU
According to European Directive 2013/35/EU, exposure limit values for protection against sensory and health effects are met if external electric or magnetic fields are below corresponding low and high action levels for head, trunk and limb exposure, respectively. In order to verify this assumption even for more realistic exposure situations deviating from strictly uniform fields, systematic numerical computations using anatomical body models exposed to worst-case magnetic field gradients in different body regions are conducted. Applying magnetic fields according to low action level to the head and high action level to trunk and limbs at the same time results in slightly increased in situ electric field strengths in central nervous system tissues, compared to uniform exposure at the low action level. The extent of this increase depends on field orientation, field gradient (slope from low to high action level), and relative position between body region and field gradient. While this increase does not lead to conflicts with the exposure limit values for frequencies of 50 Hz and higher, violation of corresponding exposure limit values could be observed at 16.67 Hz.