Investigation of Extremely Low Frequency Magnetic Field (ELF-MF) Flux Densities in the Vicinity of Schools in Tehran

Epidemiologic studies have shown the relation between exposure to extremely low frequency magnetic fields (ELF-MFs) and childhood leukemia, so assessment of children exposure levels in different environments is considered as a serious precedence. Present study aimed at determining ELF-MFs flux densities near schools in Tehran. Measurements were performed near randomly selected schools in three different periods of time (i.e. 6-9 PM, 9-12 AM and 12-3 AM) using HI-3604 Power Frequency Field Strength Measurement System according to IEEE standard procedure. Data analysis was done using ANOVA test. Mean, maximum and minimum ELF-MFs flux density were 0.147±0.08 μT, 0.6130 μT and 0.0237 μT, respectively. There was no significant difference neither among different periods of time nor among different schools located at different parts of the city. According to the results from this study, although ELF-MFs flux density in Tehran’s schools is significantly lower than ICNIRP guidelines (0.15%), one third of cases still exceed the value of 0.2 μT, which is considered as a baseline for increased risk of childhood leukemia. In addition, since magnetic flux density rapidly decreases as the distance from the source increases, its spatio-temporal variations can not be observed in locations far from the sources. For the same reason, exposure of schoolchildren to ELF-MFs in Tehran’s schools is only considerable in long-term aspect. Results of present study can be used for computation of schoolchildren’s total exposure to ELF-MFs in different environments.