• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.5 s.108
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• pp.451-460
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• 2006

We have designed local exposure systems for long-time mice experiments in PCS and cellular frequency band(PCS: 1,762.5 MHz, cellular: 848.5 MHz). The fabricated systems are local exposure systems of carousel type, and 40 mice can be exposed at a time. In order not to give extra stress to the mice ender experiment, the systems were fabricated to meet the environmental conditions such as illumination, ventilation, noise etc. SAR measurement was performed using a temperature probe. Measurements at 3 points in the head of mouse cadaver and solid phantom were made, and it has been confirmed that the measurement results are in good agreement with the simulation results in the real exposure environment. The exposure systems are currently used for long-term mice experiments.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.45 no.3
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• pp.59-67
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• 2008

Due to the fast increase in cellular phone users, public interest on health effect of electromagnetic fields(EMFs) by cellular phonos is gradually increasing. Some EHS(electromagnetic hypersensitivity) patients complain of psycho-neurophysiological symptoms such as headaches, insomnia, memory loss resulting from RF radiation by CDMA cellular phones. However, EHS is difficult to diagnose and depends on the individual's subjective judgement. And we don't know clearly if the cause of EHS is uneasiness or real exposure. There have been various EHS volunteer studies on heart rate, blood pressure and subjective symptoms using GSM phones. But there are few studies on experimental case-control study investigating physiological parameters, subjective symptoms, and perception of EMFs. In this study, two volunteer groups of 17 self-declared EHS and 19 controls were exposed to both sham and real RF exposure by CDMA cellular phones for half an hour each. We investigated not only the physiological parameters such as heart rates, respiration rates and HRVs(hear rate variability), but also the perception of EMFs and subjective symptoms. As the results, EMF exposure did not have any effects on the subjective symptoms or physiological parameters for both groups. For the EMF perception, there was no evidence that EHS group perceived the EMFs correctly than the control group.

• Science of Emotion and Sensibility
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• v.13 no.4
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• pp.721-732
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• 2010

As increasing of electrical device usage, social concerns about the possible effects of 60Hz electromagnetic fields (EMF) on human health have increased. The number of people with self-attributed electromagnetic hypersensitivity (EHS) who complain of subjective symptoms such as headache, insomnia etc. also increased. However, we don't know whether the EHS results from psychological factor or real perception to the electromagnetic field. In this study, we simultaneously investigated physiological changes(heart rate, respiration rate, heart rate variability, alpha and beta waves in EEG), subjective symptoms and perception accuracy to assess origins of subjective symptoms according to the EMF exposure. Experiment consists of real and sham sessions and 60Hz 12.5uT magnetic field was on(real) or off(sham) to 15 EHS and 16 nonEHS. As the results, EMF exposure did not have any effects on physiological parameters or subjective symptoms for both groups. There was also no evidence that EHS group perceived the EMFs correctly than the control group. Therefore, the origins of subjective symptoms is not the 60Hz magnetic field but psychological factors.

• Journal of Science and Technology Studies
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• v.8 no.1
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• pp.97-129
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• 2008

We are living in the time of high probability of technological risk due to increased rate of technology development and diffusion of new technologies. Resolving uncertainties, the basic attribution of risk, by accumulating knowledge over the risk factors of certain technology is critical to management of technological risk. In many cases of technological risks, high uncertainty of knowledge is commonly mentioned reason for public controversies on risk management. However, the type of technological risk with low social agreement and low uncertainty of knowledge, the main reason for public controversy is absence of social agreement. Public debates on the risks of mobile phones electromagnetic fields(EMF) to human health comes under this category. The knowledge uncertainty on human health effect of mobile phones EMF has been lowered increasingly by accumulating enormous volume of knowledge though scientists have not reached a final conclusion whether it pose a risk to the physical and mental health of the general population or not. In contrast with civil organizations calling for precautionary approach based regulation, the mobile phone industry is cling to the position of no-regulation-needed by arguing no clear evidence to prove health risks of mobile phone EMF has found. In Korea, government set exposure standards based on a measurement called the 'specific absorption rate'(SAR) and require the mobile phone industry to open SAR information to the public by their own decision. From the view of pro-regulation side based on precautionary approach, technology risk managament of mobile phones EMF in Korea is highly limited and formalized one with limited measuring of SAR on head part only and problematic self-regulated opening of information about SAR to the public. As far as the government keeps having priority on protecting interest of mobile phone industry over precautionary regulation of mobile phones EMF, the disagreement between civil organizations and the government will not resolved. The risk of mobile phones EMF to human health have high probability of being underestimated in the rate and damage of risk than objectively estimated ones due to familiarity of mobile phone technology. And this can be the cause of destructive social dispute or devastating disaster. To prevent such disastrous results, technology risk management, which integrating the goals of safety with economic growth in public policy and designing and promoting risk communication, is required.

• Journal of the Korean Society of Safety
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• v.36 no.4
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• pp.20-28
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• 2021

With an increase in the commercialization of electricity, and the development of advanced and large electric devices and various wireless radio wave services, concerns over the effects of electromagnetic fields on human health have increased. Accordingly, the World Health Organization encouraged the development of international standards by establishing the 'International Electromagnetic Fields Project' in 1996 based on studies on the harmful effects of electromagnetic fields on the human body. Moreover, the National Institute of Environmental Health Sciences (NIEHS) classified electromagnetic fields as possible carcinogens under Group 2B category, even though they have been found to have a weak correlation with those effects on human health. Mid-to-large-sized electric facilities used at industrial sites mostly adopt a commercial frequency of 60 Hz, and workers handling these facilities are exposed to such extremely low frequency (ELF) fields for a long time. A previous study suggested that exposure to ELF electromagnetic fields with frequency ranges from 0 to 300 Hz, even for a short time, at densities higher than 100 μT may have harmful effects on human body as it affects the activation of nerve cells in the central nervous system by inducing an electric field and current and stimulating muscles and the nervous system in the body. Such studies, however, focused on home appliances used by ordinary people, and research on facilities utilizing high-capacity current and operated by workers at industrial sites is lacking. Therefore, in this study, a 3000 kilowatt generator, which is a high-capacity electric facility employed at industrial sites, was investigated, and the size of the magnetic fields generated during its no-load and high-load operations per distance to produce a map was measured to reveal spots deemed hazardous according to domestic and international exposure standards. The findings of this study is expected to alleviate workers' anxiety about the harmful effects of magnetic fields on their body and to minimize the level of exposure during operations.

• Journal of electromagnetic engineering and science
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• v.15 no.3
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• pp.142-150
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• 2015

Several reports supported that continuous exposure to 60 Hz magnetic field (MF) induces testicular germ cell apoptosis in vivo. We recently evaluated duration- and dose-dependent effects of continuous exposure to a 60 Hz MF on the testes in mice. BALB/c male mice were exposed to a 60 Hz MF at $100{\mu}T$ for 24 hours a day for 2, 4, 6, or 8 weeks, and at 2, 20 or $200{\mu}T$ for 24 hours a day for 8 weeks. To induce the apoptosis of testicular germ cell in mice, the minimum dose is $20{\mu}T$ at continuous exposure to a 60 Hz MF for 8 weeks, and the minimum duration is 6 weeks at continuous exposure of $100{\mu}T$. Continuous exposure to a 60 Hz MF might affect duration- and dose-dependent biological processes including apoptotic cell death and spermatogenesis in the male reproductive system of mice. The safety guideline of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) indicates that the permissible maximum magnetic flux density for general public exposure is $200{\mu}T$ at 60 Hz EMF (ICNIRP Guidelines, 2010). In the present study, we aimed to examine the expression of pro- and anti-apoptotic genes regulated by the continuous exposure to 60 Hz at $200{\mu}T$ in Sprague-Dawley rats for 20 weeks. The continuous exposure to 60 Hz at $200{\mu}T$ does not affect the body and testicular weight in rats. However, exposure to 60 Hz MF significantly affects testicular germ cell apoptosis and sperm count. Further, the apoptosis-related gene was scrutinized after exposure to 60 Hz at $200{\mu}T$ for 20 weeks. We found that the message level of endonuclease G (EndoG) was greatly increased following the exposure to 60 Hz at $200{\mu}T$ compared with sham control. These data suggested that 60 Hz magnetic field induced testicular germ cell apoptosis through mitochondrial protein Endo G.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.1
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• pp.106-112
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• 2013

In this paper, human exposure of wireless devices was analyzed for various positions of the transmitter. The scenario for the position of the transmitting antenna was decided after discussion with ADD(Agency for Defense Development), and Korean male phantom model developed by ETRI were used to conduct simulations. The SAR values were analyzed by changing the position of the transmitter, and compared with Korean EMF regulations and ICNIRP guidelines. Additionally, human exposure was also investigated for two typical postures which can be posed by war-fighter.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.4
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• pp.509-517
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• 2014

Objectives: This study was conducted to investigate the patterns of exposure of welders to strong magnetic fields for extended periods of time on the basis of their daily activities as recorded in a logbook. Methods: Male workers whose main job is welding, specifically seven welders occupied with gas tungsten arc welding(GTAW), two performing shielded metal arc welding(SMAW), and ten engaged in gas metal arc welding(GMAW), were measured in terms of the degree to which they were exposed to extremely low frequency(ELF) magnetic fields over 24 hours by using an electromagnetic field meter(EMF meter), as well as based on a daily activity log. Results: The welders were exposed to $1.25{\pm}4.95{\mu}T$ of magnetic field per day on average. For those who spent more than half a day-735.26 minutes, or 51.1% of the day-at work, the figure averages $3.88{\pm}8.85{\mu}T$ with a maximum value of $221.28{\mu}T$. The subject welders spent $338.14{\pm}154.95$ minutes per day at home. During their stays at home, they were exposed to an average of $0.17{\pm}0.06{\mu}T$ with a maximum value of $3.50{\mu}T$. The maximum exposure of $221.28{\mu}T$ occurred when welders performed GMAW. The average exposure reached its highest at $17.71{\pm}6.96{\mu}T$ when conducting SMAW. Magnetic field exposure also depends upon posture: welders who sat while welding were exposed five times more than those who stood during work, and this difference is statistically significant. As for the relationship between distance from the welding power supply and maximum magnetic field exposure, maximum magnetic field exposure decreases as the distance increases. The average magnetic field exposure, in the meantime, showed no significant difference depending on distance. Conclusions: The following were observed through this study: 1) welders, while conducting jobs, are exposed to magnetic fields not only from the welding machine, but also from the surrounding base material due to the current flowing between the welding machine and base material, meaning that they are continuously exposed to a magnetic field; and 2) welders are more exposed to magnetic fields while they sit at a job compared to when they stand up.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.1
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• pp.42-51
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• 2012

Objectives: To compare the exposure level of extremely low frequency (ELF) magnetic fields among semiconductor workers, shipyard welders and office workers. Methods: To measure the ELF magnetic field concentration, EMDEX LITE (Enertech, USA) were used and monitored for eight hours continuously. Five companies handling the electric and magnetic field (EMF) source were investigated, which the exposure groups were classified into three groups: semiconductor workers, welders, and office workers. Welder group was chosen as a high exposed group and office group as a low exposed group. Results: The arithmetic mean (${\pm}SD$) and geometric mean (GSD) of personal exposure level of semiconductor workers were 0.73 (${\pm}1.33$) ${\mu}T$, 0.43 (2.88) ${\mu}T$, respectively. The ceiling value ranged between 0.18 and 123.2 ${\mu}T$. Welders were exposed high with the arithmetic mean value of 3.46 (${\pm}\;13.46$) ${\mu}T$ and geometric mean value of 0.45 (4.70) ${\mu}T$, respectively, and ceiling value range of 75.5~129.6 ${\mu}T$. The exposure levels of office workers were low compared to other exposed groups; the arithmetic mean 0.05 (${\pm}0.13$) ${\mu}T$, geometric mean 0.03 (2.38) ${\mu}T$ and ceiling value range 0.37~3.35 ${\mu}T$. This study revealed statistically significant differences of the mean ELF magnetic field exposure doses among three groups (p < 0.01). Conclusions: The average ELF magnetic field exposure doses of semiconductor workers were much higher than those of office workers in control group, but were lower than those of welders in high exposure group.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.425-428
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• 2005

A variety of wireless devices are commercially available now. Most of studies, however, have been directed to the biological effects of mobile-phone EMF. In this study, dosimetric analysis for wireless devices of head-mounted display type and a wristwatch type were made to investigate possible biological effects of these devices. SAR (Specific Absorption Rate) distributions were calculated using FDTD (Finite Difference Time Domain) method, for adult human models such as standard Korean human model and VHP(Visible Human Project) model, as well as scaled models. Measurements were also performed for SAM phantom wearing a simplified prototype for a wireless device for validation of the simulation results. It has been found that children are more vulnerable to such exposure, and these devices could cause some biological effects for relatively lower power compared to conventional mobile pones.