Extremely Low Frequency (ELF) magnetic fields are produced by the flow of electrical current. They are measured in milligauss (mG) or microtesla (µT). Unlike electric fields, magnetic fields easily penetrate walls and most materials.
Based on Building Biology Institute guidelines (mG (milligauss)):
See where common exposures fall on the scale:
Showing 486 studies with measured magnetic fields (elf) exposure
Kantar Gok D et al. · 2014
Researchers exposed rats to 50 Hz electric fields (like those from power lines) for up to four weeks. High-intensity exposure significantly reduced brain responses that help detect sound changes, while increasing brain damage markers. This suggests electric field exposure may impair auditory processing abilities.
Ross ML, Koren SA, Persinger MA. · 2008
Researchers tested whether a weak magnetic field pulsed over the left prefrontal brain region at the moment of accepting or refuting a statement could increase the likelihood of later accepting a false statement as true. Fifty men and women were each exposed to one of four magnetic field conditions, or a sham field, over the left prefrontal region above the eyebrow. Groups that received the burst-firing or 25 Hz pulsed fields during the refutation process accepted about twice the number of false statements as true compared to those in the 50 Hz or sham-field conditions. The treatments did not significantly affect the numbers of true statements accepted as false.
Sage C, Johansson O, Sage SA · 2007
Novoselova EG, Ogai VB, Sorokina OV, Novikov VV, Fesenko EE · 2001
Researchers studied the effect of fractionated low-intensity microwave exposure and a combined weak magnetic field on tumor necrosis factor production in macrophages of mice with experimental solid tumors. Exposure to both microwaves and magnetic field enhanced the adaptive response, with higher tumor necrosis factor production in peritoneal macrophages of exposed tumor-bearing mice compared to unexposed mice.
André-Jean Berteaud et al. · 1971
André-Jean Berteaud et al. · 1971
This 1971 French study examined how pulsed and modulated electromagnetic radiation affects the development of Trypanosoma equiperdum infections in laboratory animals. The research investigated whether UHF electromagnetic waves could influence parasitemia (parasite levels in blood) during infection progression. This represents early biological research into how electromagnetic fields might interact with infectious disease processes.
S. S. Kronenberg, T. S. Tenforde · 1979
Bellieni CV et al. · 2012
Researchers measured electromagnetic fields from five laptop computers of different brands and used computerized models to estimate induced currents in adult users and fetuses. The measured EMF values ranged from 1.8 to 6 μT, which fell within ICNIRP guidelines but were considerably higher than levels recommended by MPR II and TCO guidelines and those considered risky for tumor development. The power supply induced electric current densities in the fetus and adult that were respectively 182–263% and 71–483% higher than ICNIRP 98 basic restrictions.
Sun W, Shen X, Lu D, Lu D, Chiang H · 2013
The radiofrequency radiation induced EGF receptor clustering and enhanced phosphorylation on tyrosine-1173 at the higher absorption rates but not at 0.1 W/kg. A 2 μT incoherent magnetic field alone did not significantly affect receptor clustering or phosphorylation. When applied together, the incoherent magnetic field completely inhibited the radiofrequency radiation effects at 0.5, 1.0, and 2.0 W/kg but not at 4.0 W/kg.
Yao K, Wu W, Wang K, Ni S, Ye P, Yu Y, Ye J, Sun L. · 2008
Researchers exposed cultured human lens epithelial cells (HLECs) to a 1.8 GHz GSM radiofrequency field for 2 hours at specific absorption rates of 1, 2, 3, and 4 W/kg, then measured intracellular reactive oxygen species (ROS) and DNA damage. After exposure to 1.8 GHz RF for 2 h, HLECs exhibited significant intracellular ROS increase in the 2, 3, and 4 W/kg groups, and RF at 3 W/kg and 4 W/kg induced significant DNA damage consisting mainly of single strand breaks. When the radiofrequency field was superposed with 2 μT electromagnetic noise, the noise blocked the RF-induced ROS increase and DNA damage.
Wu W, Yao K, Wang KJ, Lu DQ, He JL, Xu LH, Sun WJ. · 2008
Researchers used the DCFH-DA method and comet assay to detect intracellular reactive oxygen species (ROS) and DNA damage in cultured human lens epithelial cells exposed to 4 W/kg 1800 MHz mobile phone radiation or 2 muT electromagnetic noise, or both, for 24 hours intermittently. 1800 MHz mobile phone radiation at 4 W/kg for 24 hours significantly increased intracellular ROS and DNA damage (P<0.05). When electromagnetic noise was added alongside the mobile phone radiation, ROS levels and DNA damage were not significantly elevated compared to sham exposure (P>0.05).
Litovitz et al. · 1997
Researchers exposed L929 cells to 60 Hz AM microwave fields or a 50 Hz burst-modulated DAMPS digital cellular phone field together with 30-100 Hz ELF noise up to 10 microT for 8 h. ODC enhancement decreased exponentially with increasing noise amplitude, with complete inhibition at 2 microT or higher for 60 Hz AM microwaves and 5 microT or higher for the DAMPS signal.
Pilla AA · 2012
Researchers tested how a non-thermal pulse-modulated RF signal affected nitric oxide release in dopaminergic MN9D neuronal cells challenged with lipopolysaccharides and in human fibroblast cultures challenged with low serum. In dopaminergic MN9D cultures, the signal produced an immediate nearly three-fold increase in nitric oxide, measured in real-time using a nitric oxide selective membrane electrode. In human fibroblast cultures challenged with low serum and exposed for 15 minutes to the same signal, nitric oxide increased nearly two-fold, and this increase could be blocked by the calmodulin antagonist W-7.
Hashish AH, El-Missiry MA, Abdelkader HI, Abou-Saleh RH · 2008
Carrubba S, Frilot C 2nd, Chesson AL Jr, Marino AA · 2010
Researchers recorded EEGs from six standard locations in 20 volunteers to detect brain potentials triggered by a pulse of the type produced by mobile phones. Evoked potentials having the expected latency were found in 90% of the volunteers, as assessed using a nonlinear method of EEG analysis. Evoked potentials were not detected when the EEG was analyzed using time averaging. The possibility of systematic error was excluded by sham-exposure analyses.
R. SUNDERMAN, T. Z. FAHIDY · 1976
Lai H, Singh NP · 2005
Researchers studied four groups of rats: one exposed to 2450-MHz microwaves at 1 mW/cm2, one to magnetic field noise at 45 mG, one to both simultaneously, and a sham-exposed group. Brain cells of microwave-exposed rats had significantly higher levels of DNA single- and double-strand breaks compared with sham-exposed animals. Noise exposure alone did not significantly affect DNA strand break levels, but simultaneous noise exposure blocked the microwave-induced increases.
Lai H, Singh NP · 2005
Researchers exposed rats to cell phone-frequency microwaves (2450 MHz) for 2 hours and found significant DNA damage in brain cells. However, when they simultaneously exposed the rats to a weak magnetic field with random fluctuations, it completely blocked the DNA damage from occurring. This suggests that certain types of magnetic field exposure might actually protect against some forms of EMF damage.
Sokolovic D et al. · 2012
Researchers exposed Wistar rats to microwave radiation for 4 hours per day and tested whether melatonin could counter any resulting changes in body mass or behaviour. A significant body mass reduction was noted in animals exposed to MW radiation when compared to controls after 20, 40 and 60 days (p<0.001). Exposed animals showed anxiety-related behaviour described as agitation and irritability after 10 days of exposure, and these changes became less noticeable after the radiation source was removed. Melatonin pretreatment significantly increased body weight in irradiated rats compared to irradiated rats without melatonin after 20 days (p<0.05), and melatonin administration caused a decrease in stress-induced behaviour.
Murugan NJ, Persinger MA. · 2014
Exposure to the patterned magnetic field reduced planarian activity by about 50%, a magnitude similar to the non-specific effects of morphine and naloxone across most dosages. A specific dosage of 100 nM produced an additional marked reduction in activity for planaria exposed to either morphine or naloxone, while only 1 pM of morphine produced this effect.
Stevens P · 2007
Researchers studied whether exposure to a 0–5 µT magnetic field at EEG alpha-band frequencies (8–12 Hz) would affect emotional state. Participants reported a change in emotional state following exposure, and a decrease in global field power was observed. The frontal alpha-asymmetry that would physiologically indicate a directly induced emotional state was absent, and researchers suggested that participant experiences were due to an interpretation of the effects of MF exposure.
Ishay JS et al. · 2007
Researchers kept Oriental hornet workers in an Artificial Breeding Box and exposed them to an AC magnetic field of a magnitude of B = 50-70 mGauss, comparing the combs they built with those from a control group exposed only to the natural terrestrial magnetic field. Exposed hornets built combs with a 35-55% smaller number of cells and fewer eggs, many deformed and imperfectly hexagonal cells, and more delicate and slender comb stems.
T. F. Budinger · 1981
The document revises previous NMR instrumentation and clinical study guidelines based on new information and reanalysis. For static magnetic fields, harmful physiological or genetic effects are not expected below 2 T. For changing magnetic fields, the induced current effect threshold is above 5 mT at 1-100 Hz, though waveform, repetition rate, maximum B field, and exposure duration need further study. RF heating guidelines set a practical upper limit of a few watts for short studies under 10 minutes and 1 W/kg for long-term studies, with power absorption estimated via RF coil Q measurements.
Bawin SM, Satmary WM, Jones RA, Adey WR, Zimmerman G. · 1996
Researchers used rat hippocampal slices to study how extremely-low-frequency (ELF) magnetic fields affect rhythmic slow activity (RSA), a brain rhythm associated with memory functions. Slices were exposed for 10-minute epochs to 1 or 60 Hz magnetic fields at intensities of 5.6, 56, or 560 μT, or were sham exposed. 1 Hz fields at 56 and 560 μT, but not at 5.6 μT, triggered irreversible destabilization of RSA intervals, while 60 Hz fields showed similar but not statistically significant trends. The field effects on RSA did not occur when nitric oxide (NO) synthesis was pharmacologically inhibited.
Mueller CH, Krueger H, Schierz C · 2002
This double-blind laboratory experiment tested whether people can perceive a 50 Hz electric and magnetic field at 100 V/m and 6 μT, and whether self-reported electromagnetic hypersensitivity (EHS) is related to that ability. A total of 63 volunteers, 49 with self-reported EHS and 14 controls, each judged 10 sham and 10 exposed two-minute blocks in randomized order. Seven of the 63 subjects reached a statistically significant result, but there was no relevant difference between self-reported EHS subjects and controls in perception success rate or in the number and types of symptoms reported.