Occupational Exposure of Train Drivers to Static and Extremely Low Frequency Magnetic Fields in Tehran Subway

Abstract

Background: Electrification of transport systems currently deserves top priority in Iran. Such systems generate a magnetic field in static or extremely low frequency ranges. Therefore, train drivers may be exposed to these fields occupationally. Objectives: The current study aimed to measure the intensity of static magnetic field (SMF) and extremely low frequency magnetic fields (ELF-MF) in the subway trains of Tehran City in different train types and situations to show drivers’ exposure to SMF and ELF-MF. Methods: Two AC and DC trains were randomly selected from lines 1 and 2, one AC train from line 4, and two ACi trains from line 5. The SMF and ELF-MF levels were measured based on BS EN 50500:2008 and recommendations in other studies using TES-1394 (ELF-MF meter) and HI-3550 (SMF meter). Ceiling values of ELF-MF and SMF were used for assessment of train driver’s exposure. One-way ANOVA, with Tukey post hoc test, and independent sample T-test were used for data analysis. Results: Maximum SMF and ELF-MF exposures were 0.52 mT (at DC trains- in trip situation) and 7.90 µT (at ACi trains- in trip situation), respectively, and the minimum exposures to SMF and ELF-MF were measured among the drivers of ACi (< 0.1 mT- in all situations) and AC trains (0.08 µT- in acceleration situation), respectively. Conclusions: As the obtained results suggest, in none of the situations, exposure of train drivers to ELF-MF and SMF exceeded the threshold limits recommended by ACGIH. However, the effects of these fields should not be ignored because different studies have reported adverse health consequences of these fields.