Background and purpose: Considerable increase on the use of electronic devices increased the rate of public occupational exposure to extremely low frequency electromagnetic fields. Assessment of exposure to these fields is highly important due to potential health hazards. This study aimed at investigating the magnetic flux emission from extremely low frequency electromagnetic fields around power lines of high voltage in Neka (north of Iran) and factors affecting the magnetic flux density.
Materials and methods: In this cross-sectional study, 50 sites around high voltage transmission lines were selected and the magnetic flux density was measured at four different distances from the lines. Humidity and temperature were measured in order to assess their impact on magnetic flux density. The extremely low-frequency magnetic field was measured using an electromagnetic field tester (model TES 1394). Statistical analysis was performed in SPSS V17 applying descriptive statistics and one-way ANOVA.
Results: The highest average magnetic flux density was at the 400 kV power transmission line (2.11 ± 1.36 µT). The average magnetic flux density was higher in the afternoon (2.55 µT) compared with that in the morning. The average values for magnetic flux density under the pylon and between two pylons were 1.18 ± 0.75 and 2.55 ± 1.42 µT, respectively. Magnetic flux density decreased by increasing distance from the wire and the environment moisture.
Conclusion: The average magnetic flux density was lower than the standards set by the international commission on non-ionizing radiation protection and American Conference of Governmental Industrial Hygienists. Hence, the health effects would be negligible.