Distribution of ELF magnetic fields in Swedish dwellings

The purpose of this study is to assess the distribution of magnetic fields in the frequency range 10 Hz-2000 Hz in randomly selected Swedish dwellings. The fields were measured in up to 3 rooms in each residence. In the master bedroom a 24 h logging of the fields was performed. The results show that 89 % of the measured houses have average magnetic fields below 0.2 μT with mean value of 0.11 μT and median value 0.05 μT. The comparison of magnetic fields in urban and rural area show that the lowest fields were found in rural areas with 97% of the residences have average magnetic fields below 0.2 μT with median value 0.04 μT. Comparing villas and apartments show that the median magnetic fields value for apartments is 0.07 μT compared to 0.04 μT for villas. The dominating frequency of the magnetic field was 50 Hz. The total harmonic distortion (THD) of the magnetic field was measured; the median value of THD was 10.3 %.