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1.
Previous investigations of exposure to electric, magnetic, or electromagnetic fields (EMF) in households were either about electricity supply EMFs or radio frequency EMFs (RF‐EMFs). We report results from spot measurements at the bedside that comprise electrostatic fields, extremely low‐frequency electric fields (ELF‐EFs), extremely low‐frequency magnetic fields (ELF‐MFs), and RF‐EMFs. Measurements were taken in 226 households throughout Lower Austria. In addition, effects of simple reduction measures (e.g., removal of clock radios or increasing their distance from the bed, turning off Digital Enhanced Cordless Telecommunication (DECT) telephone base stations) were assessed. All measurements were well below International Commission on Non‐Ionizing Radiation Protection (ICNIRP) guideline levels. Average night‐time ELF‐MFs (long‐term measurement from 10 pm to 6 am, geometric mean over households) above 100 nT were obtained in 2.3%, and RF‐EMFs above 1000 µW/m2 in 7.1% of households. Highest ELF‐EFs were primarily due to lamps beside the bed (max = 166 V/m), and highest ELF‐MFs because of transformers of devices (max = 1030 nT) or high current of power lines (max = 380 nT). The highest values of RF‐EMFs were caused by DECT telephone base stations (max = 28979 µW/m2) and mobile phone base stations (max = 4872 µW/m2). Simple reduction measures resulted in an average decrease of 23 nT for ELF‐MFs, 23 V/m for ELF‐EFs, and 246 µW/m2 for RF‐EMFs. A small but statistically significant correlation between ELF‐MF exposure and overall RF‐EMF levels of R = 0.16 (P = 0.008) was computed that was independent of type (flat, single family) and location (urban, rural) of houses. Bioelectromagnetics 31:200–208, 2010. © 2009 Wiley‐Liss, Inc.  相似文献   

2.
The main purpose of this work was to investigate the fluctuation of Greek indoor electromagnetic field (EMF) intensity values and identify peaks that might occur. The scientific interest is mainly focused on the bands of extremely low-frequency (ELF) magnetic fields and radiofrequency (RF) electric fields which have been suggested to be possibly carcinogenic to humans by the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR).Electromagnetic radiation (EMR) measurements were performed in a variety of indoor dwellings, in Attica and in the islands of Zakynthos and Lesvos.A total number of 4540 measurements were taken in a wide frequency range (50 Hz–2100 MHz) of which 3301 in Attica, 963 in Lesvos and 276 in Zakynthos.Statistical analysis of the data revealed specific statistically significant differences between the mean values of the electric (ELF and RF) but not the magnetic (ELF) field strengths measured at different distances from the EMF source, as well as between some of the mean values of the RF electric field at different bands. Some statistically significant differences between mean electric field values at different geographic locations were also identified.As far as the RF electric field is concerned, the maximum values, in most cases, were below 0.5 V/m, however increased values above 1 V/m and up to 5.6 V/m were occasionally observed. The ELF magnetic field values were lower than 1 μT. It may be concluded that overall, the observed indoor EMF intensity values remained well below domestic and European established limits.  相似文献   

3.
4.
Human exposure to background radiofrequency electromagnetic fields (RF‐EMF) has been increasing with the introduction of new technologies. There is a definite need for the quantification of RF‐EMF exposure but a robust exposure assessment is not yet possible, mainly due to the lack of a fast and efficient measurement procedure. In this article, a new procedure is proposed for accurately mapping the exposure to base station radiation in an outdoor environment based on surrogate modeling and sequential design, an entirely new approach in the domain of dosimetry for human RF exposure. We tested our procedure in an urban area of about 0.04 km2 for Global System for Mobile Communications (GSM) technology at 900 MHz (GSM900) using a personal exposimeter. Fifty measurement locations were sufficient to obtain a coarse street exposure map, locating regions of high and low exposure; 70 measurement locations were sufficient to characterize the electric field distribution in the area and build an accurate predictive interpolation model. Hence, accurate GSM900 downlink outdoor exposure maps (for use in, e.g., governmental risk communication and epidemiological studies) are developed by combining the proven efficiency of sequential design with the speed of exposimeter measurements and their ease of handling. Bioelectromagnetics 34:300–311, 2013. © 2012 Wiley Periodicals, Inc.  相似文献   

5.
Abstract

Measurements of extremely low frequency (ELF) magnetic fields were conducted in the environment of commercial laboratory equipment in order to evaluate the possible co-exposure during the experimental processes on cell cultures. Three types of device were evaluated: a cell culture CO2 incubator, a thermostatic water bath and a laboratory shaker table. These devices usually have electric motors, heating wires and electronic control systems, therefore may expose the cell cultures to undesirable ELF stray magnetic fields. Spatial distributions of magnetic field time domain signal waveform and frequency spectral analysis (FFT) were processed. Long- and short-term variation of stray magnetic field was also evaluated under normal use of investigated laboratory devices. The results show that the equipment under test may add a considerable ELF magnetic field to the ambient environmental magnetic field or to the intentional exposure to ELF, RF or other physical/chemical agents. The maximum stray magnetic fields were higher than 3?µT, 20?µT and 75?µT in the CO2 incubator, in water bath and on the laboratory shaker table, respectively, with high variation of spatial distribution and time domain. Our investigation emphasizes possible confounding factors conducting cell culture studies related to low-level ELF-EMF exposure due to the existing stray magnetic fields in the ambient environment of laboratory equipment.  相似文献   

6.
This paper gives a brief review of the physical interaction and bio-effects of exposure to extremely low frequency (ELF) electromagnetic fields (EMF) along with guidelines on limits of exposure to 50/60 Hz electric and magnetic fields.  相似文献   

7.
This study aims to assess the levels of extremely low frequency magnetic fields (ELF‐MF) emitted from portable hand‐held fans (HHFs) and their principal frequency and to identify factors influencing these levels. We collected a total of eleven models of HHF and monitored the ELF‐MF as a function of fan speed and distance from the fan. EMDEX II was used to monitor the ELF‐MF. An SMP2 EMF‐meter equipped with a P400 field probe was used to determine the levels of ELF‐MF and the frequency spectrum. Ten of the fans, excluding only one bladeless‐fan model, emitted a high level of ELF‐MF near the source of the HHF direct‐current motor. The maximum measured level of ELF‐MF ranged from 14.07 to 218.7 µT. All measurements of the ELF‐MF taken within 10 cm from the HHFs showed values higher than 1.0 µT. ELF‐MF levels were found to decrease markedly with distance, regardless of the HHF product. The level of ELF‐MF rose noticeably with increased fan speed. The speed of and distance from the HHF significantly influenced the level of ELF‐MF. All principal frequencies ranged from 1 to 300 Hz, which falls in the typical range of ELF. Bioelectromagnetics. 2019;40:569–577. © 2019 Bioelectromagnetics Society.  相似文献   

8.
The fourth course at the International School of Bioelectromagnetics addressed various aspects of the epidemiology of exposure to electromagnetic fields (EMF). In this overview, inspired by the lectures and the discussions among participants, we summarize current knowledge on exposure to EMF and disease risk, with emphasis on studies of use of mobile phones and brain tumours and exposure to power lines and childhood leukaemia. Sources of bias and error hamper straightforward conclusions in some areas and, in order to move forward, improvements in study design and exposure assessment are necessary. The scientific evidence available to date on possible long‐term effects from exposure to ELF and RF fields is not strong enough to revise current protection limits based on the known acute effects of such exposures. Precautionary measures may be considered to reduce ELF exposure of children or exposure to RF during mobile phone use, keeping in mind that it is unclear whether they involve any preventive benefit. Possible health effects from mobile phone use in adults and in children should be investigated further by prospective epidemiological studies with improved exposure assessment and brain tumour incidence rates should be monitored. Further studies on the relation between childhood leukaemia and ELF magnetic fields would be worthwhile if they focus on heavily exposed groups and attempt to minimize possible selection bias. In conclusion, epidemiological studies conducted with appropriate diligence can play a key role in finding the answers. Bioelectromagnetics 30:511–524, 2009. © 2009 Wiley‐Liss, Inc.  相似文献   

9.
Extremely low‐frequency electromagnetic fields (ELF‐EMFs) may cause negative health effects. This study aimed to investigate the direct and indirect effects of chronic exposure to extremely low‐frequency electric and magnetic fields on the prevalence of musculoskeletal disorders (MSDs). In this cross‐sectional study, 152 power plant workers were enrolled. The exposure level of employees was measured based on the IEEE Std C95.3.1 standard. Superoxide dismutase (SOD), catalase (Cat), glutathione peroxidase (GPx), total antioxidant capacity (TAC), and malondialdehyde (MDA) (independent variables) were measured in the serum of subjects. The Nordic musculoskeletal questionnaire was used to assess MSDs (dependent variable). The mean exposure of electric and magnetic fields were 4.09 V/m (standard deviation [SD] = 4.08) and 16.27 µT (SD = 22.99), respectively. Increased levels of SOD, Cat, GPx, and MDA had a direct significant relation with MSDs. In the logistic regression model, SOD (odds ratio [OR] = 0.952, P = 0.026), GPx (OR = 0.991, P = 0.048), and MDA (OR = 0.741, P = 0.021) were significant predictors of MSDs. ELF‐EMFs were not related to MSDs directly; however, increased levels of oxidative stress may cause MSDs. Bioelectromagnetics. 2019;40:354–360. © 2019 Bioelectromagnetics Society.  相似文献   

10.
An energy-efficient lighting retrofit at the Food and Drug Administration (FDA) Winchester Engineering and Analytical Center (WEAC) presented the opportunity to measure the electromagnetic (EM) environments in several rooms before and after changing the fluorescent lighting systems and to compare the changes in EM fields with the proposed standard EM immunity levels. Three rooms, representing the types of work areas in the laboratory, were selected and measured before and after the lighting changeover. Electric and magnetic field measurements were taken in the extremely low frequency (ELF), very low frequency (VLF), and radio frequency (RF) ranges of the EM spectrum. In 2 rooms, ELF electric fields were reduced and VLF and RF electric fields were increased as a result of the changeover to high-frequency fixtures. A third room received low-frequency, energy-efficient fixtures during this changeover, and this change resulted in only a slight increase of the ELF electric fields. The ELF magnetic fields were greatly reduced in 2 but only slightly reduced in the third room. No significant change was seen in VLF or RF magnetic fields for any of these rooms. Some field-strength measurements exceeded the proposed immunity levels recommended in the draft International Electrotechnical Commission standard IEC 60601-1-2 (rev. 2). The data show that increasing the separation distance from the fluorescent light fixtures greatly reduces the field-strength levels, limiting the potential for EM interference.  相似文献   

11.
The debate as to whether low-level electromagnetic fields can affect biological systems and in the long term cause health effects has been going on for a long time. Yet the interaction of weak electromagnetic fields (EMF) with living cells, undoubtedly a most important phenomenon, is still not well understood. The exact mechanisms by which the effects are produced have not been identified. Furthermore, it is not possible to clearly define which aspects of an EMF exposure that constitute the “dose.” One of the groups that contributed to solving this problem is the Bioelectromagnetics group at Catholic University of America (CUA), Washington, D.C. Their work has been devoted to investigating the physical parameters that are needed to obtain an effect of EMF exposure on biological systems, and also how to inhibit the effect. This is a review of their work on bioeffects caused by low-level EMF, their dependence on coherence time, constancy, spatial averaging, and also how the effects can be modified by an applied ELF noise magnetic field. The group has been using early chick embryos, and L929 and Daudi cells as their main experimental systems. The review also covers the work of other groups on low-level effects and the inhibition of the effects with an applied noise field. The group at CUA has shown that biological effects can be found after exposure to low-level ELF and RF electromagnetic fields, and when effects are observed, applying an ELF magnetic noise field inhibits the effects. Also, other research groups have tried to replicate the studies from the CUA group, or to apply EMF noise to suppress EMF-induced effects. Replications of the CUA effects have not always been successful. However, in all cases where the noise field has been applied to prevent an observed effect, it has been successful in eliminating the effect.  相似文献   

12.
Electric, magnetic, and electromagnetic fields are ubiquitous in our society, and concerns have been expressed regarding possible adverse effects of these exposures. Research on Extremely Low-Frequency (ELF) magnetic fields has been performed for more than two decades, and the methodology and quality of studies have improved over time. Studies have consistently shown increased risk for childhood leukemia associated with ELF magnetic fields. There are still inadequate data for other outcomes. More recently, focus has shifted toward Radio Frequencies (RF) exposures from mobile telephony. There are no persuasive data suggesting a health risk, but this research field is still immature with regard to the quantity and quality of available data. This technology is constantly changing and there is a need for continued research on this issue. To investigate whether exposure to high-frequency electromagnetic fields (EMF) could induce adverse health effects, we cultured acute T-lymphoblastoid leukemia cells (CCRF-CEM) in the presence of 900?MHz MW-EMF generated by a transverse electromagnetic (TEM) cell at short and long exposure times. We evaluated the effect of high-frequency EMF on gene expression and we identified functional pathways influenced by 900?MHz MW-EMF exposure.  相似文献   

13.
This study aimed to determine the effect of extremely low‐frequency electromagnetic fields (ELF‐EMF) on the physiological response of phagocytes to an infectious agent. THP‐1 cells (human monocytic leukemia cell line) were cultured and 50 Hz, 1 mT EMF was applied for 4–6 h to cells induced with Staphylococcus aureus or interferon gamma/lipopolysaccharide (IFγ/LPS). Alterations in nitric oxide (NO), inducible nitric oxide synthase (iNOS) levels, heat shock protein 70 levels (hsp70), cGMP levels, caspase‐9 activation, and the growth rate of S. aureus were determined. The growth curve of exposed bacteria was lower than the control. Field application increased NO levels. The increase was more prominent for S. aureus‐induced cells and appeared earlier than the increase in cells without field application. However, a slight decrease was observed in iNOS levels. Increased cGMP levels in response to field application were closely correlated with increased NO levels. ELF‐EMF alone caused increased hsp70 levels in a time‐dependent manner. When cells were induced with S. aureus or IFγ/LPS, field application produced higher levels of hsp70. ELF‐EMF suppressed caspase‐9 activation by a small extent. These data confirm that ELF‐EMF affects bacterial growth and the response of the immune system to bacterial challenges, suggesting that ELF‐EMF could be exploited for beneficial uses. Bioelectromagnetics 31:603–612, 2010. © 2010 Wiley‐Liss, Inc.  相似文献   

14.
Although melatonin (MT) has been reported to protect cells against oxidative damage induced by electromagnetic radiation, few reports have addressed whether there are other protective mechanisms. Here, we investigated the effects of MT on extremely low‐frequency electromagnetic field (ELF‐EMF)‐induced Nav activity in rat cerebellar granule cells (GCs). Exposing cerebellar GCs to ELF‐EMF for 60 min. significantly increased the Nav current (INa) densities by 62.5%. MT (5 μM) inhibited the ELF‐EMF‐induced INa increase. This inhibitory effect of MT is mimicked by an MT2 receptor agonist and was eliminated by an MT2 receptor antagonist. The Nav channel steady‐state activation curve was significantly shifted towards hyperpolarization by ELF‐EMF stimulation but remained unchanged by MT in cerebellar GC that were either exposed or not exposed to ELF‐EMF. ELF‐EMF exposure significantly increased the intracellular levels of phosphorylated PKA in cerebellar GCs, and both MT and IIK‐7 did not reduce the ELF‐EMF‐induced increase in phosphorylated PKA. The inhibitory effects of MT on ELF‐EMF‐induced Nav activity was greatly reduced by the calmodulin inhibitor KN93. Calcium imaging showed that MT did not increase the basal intracellular Ca2+ level, but it significantly elevated the intracellular Ca2+ level evoked by the high K+ stimulation in cerebellar GC that were either exposed or not exposed to ELF‐EMF. In the presence of ruthenium red, a ryanodine‐sensitive receptor blocker, the MT‐induced increase in intracellular calcium levels was reduced. Our data show for the first time that MT protects against neuronal INa that result from ELF‐EMF exposure through Ca2+ influx‐induced Ca2+ release.  相似文献   

15.
A novel exposure system for double-blind human electromagnetic provocation studies has been developed that satisfies the precision, control of fields and potential artifacts, and provides the flexibility to investigate the response of hypotheses-driven electromagnetic field exposure schemes on brain function, ranging from extremely low frequency (ELF) to radio frequency (RF) fields. The system can provide the same exposure of the lateral cerebral cortex at two different RF frequencies (900 and 2140 MHz) but with different exposure levels at subcortical structures, and also allows uniform ELF magnetic field exposure of the brain. The RF modulation and ELF signal are obtained by a freely programmable arbitrary signal generator allowing a wide range of worst-case exposure scenarios to be simulated, including those caused by wireless devices. The maximum achievable RF exposure is larger than 60 W/kg peak spatial specific absorption rate averaged over 10 g of tissue. The maximum ELF magnetic field exposure of the brain is 800 A/m at 50 Hz with a deviation from uniformity of 8% (SD).  相似文献   

16.
It has recently been reported that the exposure of human spermatozoa to an extremely low frequency (ELF) electromagnetic field (EMF) with a square waveform of 5 mT amplitude and frequency of 50 Hz improves sperm motility. The functional relationship between the energy metabolism and the enhancement of human sperm motility induced by ELF‐EMF was investigated. Sperm exposure to ELF‐EMF resulted in a progressive and significant increase of mitochondrial membrane potential and levels of ATP, ADP and NAD+ that was associated with a progressive and significant increase in the sperm kinematic parameters. No significant effects were detected on other parameters such as ATP/ADP ratio and energy charge. When carbamoyl cyanide m‐chlorophenylhydrazone (CICCP) was applied to inhibit the oxidative phosphorylation in the mitochondria, the values of energy parameters and motility in the sperm incubated in the presence of glucose and exposed to ELF‐EMF did not change, thus indicating that the glycolysis was not involved in mediating ELF‐EMF stimulatory effect on motility. By contrast, when pyruvate and lactate were provided instead of glucose, the energy status and motility increased significantly in ELF‐EMF‐treated sperm. Under these culture conditions, the inhibition of glycolitic metabolism by 2‐deoxy‐D ‐glucose (DOG) again resulted in increased values of energy and kinematic parameters, indicating that gluconeogenesis was not involved in producing glucose for use in glycolysis. We concluded that the key role in mediating the stimulatory effects exerted by ELF‐EMF on human sperm motility is played by mitochondrial oxidative phosphorylation rather than glycolysis. Bioelectromagnetics 32:15–27, 2011. © 2010 Wiley‐Liss, Inc.  相似文献   

17.
The aim of this study was to assess the influence of cisplatin and an extremely low frequency electromagnetic field (ELF‐EMF) on antioxidant enzyme activity and the lipid peroxidation ratio, as well as the level of DNA damage and reactive oxygen species (ROS) production in AT478 carcinoma cells. Cells were cultured for 24 and 72 h in culture medium with cisplatin. Additionally, the cells were irradiated with 50 Hz/1 mT ELF‐EMF for 16 min using a solenoid as a source of the ELF‐EMF. The amount of ROS, superoxide dismutase (SOD) isoenzyme activity, glutathione peroxidase (GSH‐Px) activity, DNA damage, and malondialdehyde (MDA) levels were assessed. Cells that were exposed to cisplatin exhibited a significant increase in ROS and antioxidant enzyme activity. The addition of ELF‐EMF exposure to cisplatin treatment resulted in decreased ROS levels and antioxidant enzyme activity. A significant reduction in MDA concentrations was observed in all of the study groups, with the greatest decrease associated with treatment by both cisplatin and ELF‐EMF. Cisplatin induced the most severe DNA damage; however, when cells were also irradiated with ELF‐EMF, less DNA damage occurred. Exposure to ELF‐EMF alone resulted in an increase in DNA damage compared to control cells. ELF‐EMF lessened the effects of oxidative stress and DNA damage that were induced by cisplatin; however, ELF‐EMF alone was a mild oxidative stressor and DNA damage inducer. We speculate that ELF‐EMF exerts differential effects depending on the exogenous conditions. This information may be of value for appraising the pathophysiologic consequences of exposure to ELF‐EMF. Bioelectromagnetics 33:641–651, 2012. © 2012 Wiley Periodicals, Inc.  相似文献   

18.
To study the effects of exposure to extremely low frequency (ELF) electric and magnetic fields (EMF) on the estrous cycle of dairy cows under short-day photoperiod, 16 non-lactating, non-pregnant Holstein cows were exposed to a vertical electric field of 10 kV/m and a horizontal magnetic field of 30 microT for 16 h per day in a cross-over design consisting of two sequences. Each sequence included three periods, and each period corresponded to the duration of one estrous cycle. All animals were maintained under short photoperiod (8 h light/16 h dark) during the trial. Exposure to EMF had an impact on the duration of a complete estrous cycle (P<0.01) and on the duration of the luteal phase (P<0.01). The mean duration of one cycle was 19.5+/-0.4 for the control and 21.3+/-0.4 days for the exposed animals, respectively. The mean duration of the luteal phase was 15.4+/-0.4 days for the control and 17.2+/-0.4 days for the exposed group. The total area under the progesterone (P(4)) curve, the amplitude of the curve or the slope of the P(4) rise at the onset of the luteal phase were not affected by EMF exposure. Results indicate that exposure to EMF may increase the duration of the estrous cycle.  相似文献   

19.
Electric field strength values calculated by wave propagation modeling were applied as an exposure metric in a case–control study conducted in Germany to investigate a possible association between radio frequency electromagnetic fields (RF‐EMF) emitted from television and radio broadcast transmitters and the risk of childhood leukemia. To validate this approach it was examined at 850 measurement sites whether calculated RF‐EMF are an improvement to an exposure proxy based on distance from the place of residence to a transmitter. Further, the agreement between measured and calculated RF‐EMF was explored. For dichotomization at the 90% quantiles of the exposure distributions it was found that distance agreed less with measured RF‐EMF (Kappa coefficient: 0.55) than did calculated RF‐EMF (Kappa coefficient: 0.74). Distance was a good exposure proxy for a single transmitter only which uses the frequency bands of amplitude modulated radio, whereas it appeared to be of limited informative value in studies involving several transmitters, particularly if these are operating in different frequency bands. The analysis of the agreement between calculated RF‐EMF and measured RF‐EMF showed a sensitivity of 76.6% and a specificity of 97.4%, leading to an exposure misclassification that still allows one to detect a true odds ratio as low as 1.4 with a statistical power of >80% at a two‐sided significance level of 5% in a study with 2,000 cases and 6,000 controls. Thus, calculated RF‐EMF is confirmed to be an appropriate exposure metric in large‐scale epidemiological studies on broadcast transmitters. Bioelectromagnetics 30:81–91, 2009. © 2008 Wiley‐Liss, Inc.  相似文献   

20.
Much of the research and reviews on extremely low frequency (ELF) electric and magnetic fields (EMFs) have focused on magnetic rather than electric fields. Some have considered such focus to be inappropriate and have argued that electric fields should be part of both epidemiologic and laboratory work. This paper fills the gap by systematically and critically reviewing electric‐fields literature and by comparing overall strength of evidence for electric versus magnetic fields. The review of possible mechanisms does not provide any specific basis for focusing on electric fields. While laboratory studies of electric fields are few, they do not indicate that electric fields should be the exposure of interest. The existing epidemiology on residential electric‐field exposures and appliance use does not support the conclusion of adverse health effects from electric‐field exposure. Workers in close proximity to high‐voltage transmission lines or substation equipment can be exposed to high electric fields. While there are sporadic reports of increase in cancer in some occupational studies, these are inconsistent and fraught with methodologic problems. Overall, there seems little basis to suppose there might be a risk for electric fields, and, in contrast to magnetic fields, and with a possible exception of occupational epidemiology, there seems little basis for continued research into electric fields. Bioelectromagnetics 31:89–101, 2010. © 2009 Wiley‐Liss, Inc.  相似文献   

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