Assessment of static and extremely low frequency magnetic fields in the electric-powered trains: An environmental and occupational perspective

摘要

Objectives: The engine and power supply of trains in advanced rail transit systems is electric (alternating current (AC) or direct current (DC)). Such systems generate magnetic fields in the range of static or extremely low frequencies. The purpose of the present study was to survey static magnetic field (SMF), and extremely low frequency magnetic field (ELF-MF) levels in the trains, and also was to assess occupational exposure level of train drivers to these fields Methods: AC and DC trains were randomly selected from intercity and metro lines. The TES-1394 and HI-3550 magnetic meter devices were used to measure ELF-MF and SMF, respectively. The exposure of train drivers was assessment in accordance with the threshold limits value of ACGIH. Results: Maximum and minimum exposure to ELF-MF were 9 μ T in intercity AC trains and 0.8 μ T in DC trains, respectively. The lowest level of SMF was reported from intercity AC trains while maximum SMF was measured at 1 mT in DC trains. Conclusions: The trains which are supplied by overhead lines can radiate more ELF-MF rather than the trains that are supplied by third rail, and so, they have more occupational and environmental hazards. However, in none of the situations, exposure of train drivers to ELF-MF and SMF exceeded the threshold limits recommended by the ACGIH.