Waveform magnetic field survey in Russian DC and Swiss AC powered trains: a basis for biologically relevant exposure assessment.
Recent epidemiological studies suggest a link between transport magnetic fields (MF) and certain adverse health effects. We performed measurements in workplaces of engineers on Russian DC and Swiss AC powered (16.67 Hz) electric trains using a computer based waveform capture system with a 200 Hz sampling rate. MF in DC and AC trains show complex combinations of static and varying components. The most probable levels of quasistatic MF (0.001-0.03 Hz) were in the range 40 microT. Maximum levels of 120 microT were found in DC powered locomotives. These levels are much higher than the geomagnetic field at the site of measurements. MF encountered both in DC and AC powered rail systems showed irregular temporal variability in frequency composition and amplitude characteristics across the whole frequency range studied (0-50 Hz); however, more than 90% of the magnetic field power was concentrated in frequencies </=16.67 Hz. In AC locomotives, such as the most popular engine Re 4/4 II, the major energy falls around the fundamental frequency 16.67 Hz, with an average magnetic field intensity of about 44 microT; moreover, a significant contribution (about 15%) is due to components below the fundamental frequency. In Russian DC powered trains amplitudes of field variations sharply decrease from static to approximately 3-4 Hz fields; for higher frequencies a tendency of slow decrease is observed up to 50 Hz. For frequencies higher than 1 Hz average amplitudes of magnetic field variations are less than 1 microT; maximum levels reach tens of microtesla. At frequencies lower than 15 Hz, the average magnetic field generated by Swiss AC powered locomotives was approximately 10 times greater than fields observed in Russian DC powered trains.
Ptitsyna
N G
NG
SPBFIZMIRAN, Department of Magnetic Measurements, St. Petersburg, Russia.
Kopytenko
Y A
YA
Villoresi
G
G
Pfluger
D H
DH
Ismaguilov
V
V
Iucci
N
N
Kopytenko
E A
EA
Zaitzev
D B
DB
Voronov
P M
PM
Tyasto
M I
MI
D011211:Electric Power Supplies; D004574:Electromagnetic Fields; D005812:Genes, Switch; D008954:Models, Biological; D015233:Models, Statistical; D016273:Occupational Exposure / Q000032:analysis*; D011874:Radiometry / Q000295:instrumentation* / Q000379:methods*; D011890:Railroads / Q000706:statistics & numerical data*; D012062:Relative Biological Effectiveness; D018570:Risk Assessment / Q000379:methods*; D012426:Russia