Assessment of exposure to extremely low frequency magnetic field emitted from monitors
Chen, C-chun.; Hong, X-yu.; Shen, G-zu.; Jin, X-peng.
Zhonghua Yu Fang Yi Xue Za Zhi 38(1): 14-17
2004
ISSN/ISBN: 0253-9624 PMID: 14989893 Document Number: 577789
Objectives To investigate intensity of extremely low frequency magnetic field (ELFMF) emitted from cathode-ray tubes ( CRT) of monitors in various directions and to find ways to avoid its influence. Methods Two hundred CRT monitors and 10 monitors with liquid-crystal display ( LCD) were selected. Their ELFMF was detected for three times in front of the monitor at an interval of every 5 cm from 0 cm to 50 cm, as well as at various directions from the monitor. Results Intensity of ELFMF significantly attenuated at regular operating position (30-40 cm) from 0 cm to 50 cm in front of both 38 cm and 43 cm CRT monitors (P 0.05). Intensity exceeded 0.4 muT both within 15 cm and 10 cm in front of 38 cm and 43 cm monitors. The highest intensity was found at the upright top position of both kinds of monitors, 9.54 muT for 38 cm monitor and 6.38 muT for 43 cm one, respectively. Conclusions It is suggested to keep away from,monitor screen as possible when operating a computer, to reduce unnecessary operation in front of a monitor screen, and to shorten operating time. To avoid more hazards from interactive interference between computers, it is necessary to increase distance between monitors.