wireless technology research paper

5G wireless technology evolution: identifying evolution pathways of core technologies based on patent networks

• Published: 28 October 2023

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• Biqiang Han 1 ,
• Jie Zhang 2 ,
• Helen Cai 3 ,
• Mengyao Xia 4 ,
• Yan Tu 5 &
• Jiao Wu 6  

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With the rapid development of 5G technology, studying its evolution path is crucial for innovation and development. This study explores the evolution of 5G technology using patent data analysis. By applying main path analysis and network techniques to a dataset from the IncoPat patent database, the study identifies the main path of 5G technology evolution and analyzes its trends. The Citespace is used to construct citation networks and reveal the main path of the patent citation network, regional citation network, and institutional citation network. Furthermore, the study incorporates the 5G technology lifecycle to dynamically interpret the main path and analyze the major evolution trends of 5G technology. The methodology includes data collection from the IncoPat patent database and the adoption of clustering analysis to identify community structure within citation networks. The Log Likelihood Ratio (LLR) algorithm is employed for community detection, facilitating the analysis of interrelationships among different communities. The main path analysis involves traversal counting and path searching, with the LLR algorithm selected to identify critical nodes in the evolutionary paths of technologies. Additionally, dynamic main path analysis is conducted by incorporating the temporal attribute, enabling the observation of the dynamic changes in technological evolution. The study concludes with important insights into the current development status and evolution of 5G technology, shedding light on key paths and trends in 5G technology evolution.

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Data Availability

The datasets generated and/or analysed during the current study are available from the corresponding author on reasonable request.

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This study was supported by the Shaoxing City Philosophy and Social Science Research ‘14th Five-Year’ Plan 2023 Key Project: A Study on the Implementation Path of Rural Revitalization Empowered by Digital Transformation under the ‘Two Mountains’ Theory from the Perspective of ‘Green Common Prosperity’ – A Case Study of Zhejiang Shaoxing (Project Number: 145J073)

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Mengyao Xia

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Han, B., Zhang, J., Cai, H. et al. 5G wireless technology evolution: identifying evolution pathways of core technologies based on patent networks. Wireless Netw (2023). https://doi.org/10.1007/s11276-023-03538-8

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DOI : https://doi.org/10.1007/s11276-023-03538-8

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• Review Article
• Open access
• Published: 16 March 2021

5G mobile networks and health—a state-of-the-science review of the research into low-level RF fields above 6 GHz

• Ken Karipidis   ORCID: orcid.org/0000-0001-7538-7447 1 ,
• Rohan Mate 1 ,
• David Urban 1 ,
• Rick Tinker 1 &
• Andrew Wood 2  

Journal of Exposure Science & Environmental Epidemiology volume  31 ,  pages 585–605 ( 2021 ) Cite this article

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The increased use of radiofrequency (RF) fields above 6 GHz, particularly for the 5 G mobile phone network, has given rise to public concern about any possible adverse effects to human health. Public exposure to RF fields from 5 G and other sources is below the human exposure limits specified by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). This state-of-the science review examined the research into the biological and health effects of RF fields above 6 GHz at exposure levels below the ICNIRP occupational limits. The review included 107 experimental studies that investigated various bioeffects including genotoxicity, cell proliferation, gene expression, cell signalling, membrane function and other effects. Reported bioeffects were generally not independently replicated and the majority of the studies employed low quality methods of exposure assessment and control. Effects due to heating from high RF energy deposition cannot be excluded from many of the results. The review also included 31 epidemiological studies that investigated exposure to radar, which uses RF fields above 6 GHz similar to 5 G. The epidemiological studies showed little evidence of health effects including cancer at different sites, effects on reproduction and other diseases. This review showed no confirmed evidence that low-level RF fields above 6 GHz such as those used by the 5 G network are hazardous to human health. Future experimental studies should improve the experimental design with particular attention to dosimetry and temperature control. Future epidemiological studies should continue to monitor long-term health effects in the population related to wireless telecommunications.

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Meta-analysis of in vitro and in vivo studies of the biological effects of low-level millimetre waves

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Radio-frequency electromagnetic field exposure and contribution of sources in the general population: an organ-specific integrative exposure assessment

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Introduction

There are continually emerging technologies that use radiofrequency (RF) electromagnetic fields particularly in telecommunications. Most telecommunication sources currently operate at frequencies below 6 GHz, including radio and TV broadcasting and wireless sources such as local area networks and mobile telephony. With the increasing demand for higher data rates, better quality of service and lower latency to users, future wireless telecommunication sources are planned to operate at frequencies above 6 GHz and into the ‘millimetre wave’ range (30–300 GHz) [ 1 ]. Frequencies above 6 GHz have been in use for many years in various applications such as radar, microwave links, airport security screening and in medicine for therapeutic applications. However, the planned use of millimetre waves by future wireless telecommunications, particularly the 5th generation (5 G) of mobile networks, has given rise to public concern about any possible adverse effects to human health.

The interaction mechanisms of RF fields with the human body have been extensively described and tissue heating is the main effect for RF fields above 100 kHz (e.g. HPA; SCENHIR) [ 2 , 3 ]. RF fields become less penetrating into body tissue with increasing frequency and for frequencies above 6 GHz the depth of penetration is relatively short with surface heating being the predominant effect [ 4 ].

International exposure guidelines for RF fields have been developed on the basis of current scientific knowledge to ensure that RF exposure is not harmful to human health [ 5 , 6 ]. The guidelines developed by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) in particular form the basis for regulations in the majority of countries worldwide [ 7 ]. In the frequency range above 6 GHz and up to 300 GHz the ICNIRP guidelines prevent excessive heating at the surface of the skin and in the eye.

Although not as extensively studied as RF fields at lower frequencies, a number of studies have investigated the effects of RF fields at frequencies above 6 GHz. Previous reviews have reported studies investigating frequencies above 6 GHz that show effects although many of the reported effects occurred at levels greater than the ICNIRP guidelines [ 1 , 8 ]. Given the public concern over the planned roll-out of 5 G using millimetre waves, it is important to determine whether there are any related adverse health consequences at levels encountered in the environment. The aim of this paper is to present a state-of-the-science review of the bioeffects research into RF fields above 6 GHz at low levels of exposure (exposure below the occupational limits of the ICNIRP guidelines). A meta-analysis of in vitro and in vivo studies, providing quantitative effect estimates for each study, is presented separately in a companion paper [ 9 ].

The state-of-the-science review included a comprehensive search of all available literature and examined the extent, range and nature of evidence into the bioeffects of RF fields above 6 GHz, at levels below the ICNIRP occupational limits. The review consisted of biomedical studies on low-level RF electromagnetic fields from 6 GHz to 300 GHz published at any starting date up to December 2019. Studies were initially found by searching the databases PubMed, EMF-Portal, Google Scholar, Embase and Web of Science using the search terms “millimeter wave”, “millimetre wave”, “gigahertz”, “GHz” and “radar”. We further searched major reviews published by health authorities on RF and health [ 2 , 3 , 10 , 11 ]. Finally, we searched the reference list of all the studies included. Studies were only included if the full paper was available in English.

Although over 300 studies were considered, this review was limited to experimental studies (in vitro, in vivo, human) where the stated RF exposure level was at or below the occupational whole-body limits specified by the ICNIRP (2020) guidelines: power density (PD) reference level of 50 W/m 2 or specific absorption rate (SAR) basic restriction of 0.4 W/kg. Since the PD occupational limits for local exposure are more relevant to in vitro studies, and since these limits are higher, we have included those studies with PD up to 100–200 W/m 2 , depending on frequency. The review included studies below the ICNIRP general public limits that are lower than the occupational limits.

The review also included epidemiological studies (cohort, case-control, cross-sectional) investigating exposure to radar but excluded studies where the stated radar frequencies were below 6 GHz. Epidemiological studies on radar were included as they represent occupational exposure below the ICNIRP guidelines. Case reports or case series were excluded. Studies investigating therapeutical outcomes were also excluded unless they reported specific bio-effects.

The state-of-the-science review appraised the quality of the included studies, but unlike a systematic review it did not exclude any studies based on quality. The review also identified gaps in knowledge for future investigation and research. The reporting of results in this paper is narrative with tabular accompaniment showing study characteristics. In this paper, the acronym “MMWs” (or millimetre waves) is used to denote RF fields above 6 GHz.

The review included 107 experimental studies (91 in vitro, 15 in vivo, and 1 human) that investigated various bioeffects, including genotoxicity, cell proliferation, gene expression, cell signalling, membrane function and other effects. The exposure characteristics and biological system investigated in experimental studies for the various bioeffects are shown in Tables  1 – 6 . The results of the meta-analysis of the in vitro and in vivo studies are presented separately in Wood et al. [ 9 ].

Genotoxicity

Studies have examined the effects of exposing whole human or mouse blood samples or lymphocytes and leucocytes to low-level MMWs to determine possible genotoxicity. Some of the genotoxicity studies have looked at the possible effects of MMWs on chromosome aberrations [ 12 , 13 , 14 ]. At exposure levels below the ICNIRP limits, the results have been inconsistent, with either a statistically significant increase [ 14 ] or no significant increase [ 12 , 13 ] in chromosome aberrations.

MMWs do not penetrate past the skin therefore epithelial and skin cells have been a common model of examination for possible genotoxic effects. DNA damage in a number of epithelial and skin cell types and at varied exposure parameters both below and above the ICNIRP limits have been examined using comet assays [ 15 , 16 , 17 , 18 , 19 ]. Despite the varied exposure models and methods used, no statistically significant evidence of DNA damage was identified in these studies. Evidence of genotoxic damage was further assessed in skin cells by the occurrence of micro-nucleation. De Amicis et al. [ 18 ] and Franchini et al. [ 19 ] reported a statistically significant increase in micro-nucleation, however, Hintzsche et al. [ 15 ] and Koyama et al. [ 16 , 17 ] did not find an effect. Two of the studies also examined telomere length and found no statistically significant difference between exposed and unexposed cells [ 15 , 19 ]. Last, a Ukrainian research group examined different skin cell types in three studies and reported an increase in chromosome condensation in the nucleus [ 20 , 21 , 22 ]; these results have not been independently verified. Overall, there was no confirmed evidence of MMWs causing genotoxic damage in epithelial and skin cells.

Three studies from an Indian research group have examined indicators of DNA damage and reactive oxygen species (ROS) production in rats exposed in vivo to MMWs. The studies reported DNA strand breaks based on evidence from comet assays [ 23 , 24 ] and changes in enzymes that control the build-up of ROS [ 24 ]. Kumar et al. also reported an increase in ROS production [ 25 ]. All the studies from this research group had low animal numbers (six animals exposed) and their results have not been independently replicated. An in vitro study that investigated ROS production in yeast cultures reported an increase in free radicals exposed to high-level but not low-level MMWs [ 26 ].

Other studies have looked at the effect of low-level MMWs on DNA in a range of different ways. Two studies reported that MMWs induce colicin synthesis and prophage induction in bacterial cells, both of which are suggested as indicative of DNA damage [ 27 , 28 ]. Another study suggested that DNA exposed to MMWs undergoes polymerase chain reaction synthesis differently than unexposed DNA [ 29 ], although no statistical analysis was presented. Hintzsche et al. reported statistically significant occurrence of spindle disturbance in hybrid cells exposed to MMWs [ 30 ]. Zeni et al. found no evidence of DNA damage or alteration of cell cycle kinetics in blood cells exposed to MMWs [ 31 ]. Last, two studies from a Russian research group examined the protective effects of MMWs where mouse blood leukocytes were pre-exposed to low-level MMWs and then to X-rays [ 32 , 33 ]. The studies reported that there was statistically significant less DNA damage in the leucocytes that were pre-exposed to MMWs than those exposed to X-rays alone. Overall, these studies had no independent replication.

Cell proliferation

A number of studies have examined the effects of low-level MMWs on cell proliferation and they have used a variety of cellular models and methods of investigation. Studies have exposed bacterial cells to low-level MMWs alone or in conjunction with other agents. Two early studies reported changes in the growth rate of E. coli cultures exposed to low-level MMWs; however, both of these studies were preliminary in nature without appropriate dosimetry or statistical analysis [ 34 , 35 ]. Two studies exposed E. coli cultures and one study exposed yeast cell cultures to MMWs alone, and before and after UVC exposure [ 36 , 37 , 38 ]. All three studies reported that MMWs alone had no significant effect on bacterial cell proliferation or survival. Rojavin et al., however, did report that when E. coli bacteria were exposed to MMWs after UVC sterilisation treatment, there was an increase in their survival rate [ 36 ]. The authors suggested this could be due to the MMW activation of bacterial DNA repair mechanisms. Other studies by an Armenian research group reported a reduction in E. coli cell growth when exposed to MMWs [ 39 , 40 , 41 , 42 , 43 , 44 , 45 ]. These studies reported that when E.coli cultures were exposed to MMWs in the presence of antibiotics, there was a greater reduction in the bacterial growth rate and an increase in the time between bacterial cell division compared with antibiotics exposure alone. Two of these studies investigated if these effects could be due to a reduction in the activity of the E. coli ATPase when exposed to MMWs. The studies reported exposure to MMWs in combination with particular antibiotics changed the concentration of H + and K + ions in the E.coli cells, which the authors linked to changes in ATPase activity [ 43 , 44 ]. Overall, the results from studies on cell proliferation of bacterial cells have been inconsistent with different research groups reporting conflicting results.

Studies have also examined how exposure to low-level MMWs could affect cell proliferation in yeast. Two early studies by a German research group reported changes in yeast cell growth [ 46 , 47 ]. However, another two independent studies did not report any changes in the growth rate of exposed yeast [ 48 , 49 ]. Furia et al. [ 48 ] noted that the Grundler and Keilmann studies [ 46 , 47 ] had a number of methodical issues, which may have skewed their results, such as poor exposure control and analysis of results. Another study exposed yeast to MMWs before and after UVC exposure and reported that MMWs did not change the rates of cell survival [ 37 ].

Studies have also examined the possible effect of low-level MMWs on tumour cells with some studies reporting a possible anti-proliferative effect. Chidichimo et al. reported a reduction in the growth of a variety of tumour cells exposed to MMWs; however, the results of the study did not support this conclusion [ 50 ]. An Italian research group published a number of studies investigating proliferation effects on human melanoma cell lines with conflicting results. Two of the studies reported reduced growth rate [ 51 , 52 ] and a third study showed no change in proliferation or in the cell cycle [ 53 ]. Beneduci et al. also reported changes in the morphology of MMW exposed cells; however, the authors did not present quantitative data for these reported changes [ 51 , 52 ]. In another study by the same Italian group, Beneduci et al. reported that exposure to low-level MMWs had a greater than 40% reduction in the number of viable erythromyeloid leukaemia cells compared with controls; however, there was no significant change in the number of dead cells [ 54 ]. More recently, Yaekashiwa et al. reported no statistically significant effect in proliferation or cellular activity in glioblastoma cells exposed to low-level MMWs [ 55 ].

Other studies did not report statistically significant effects on proliferation in chicken embryo cell cultures, rat nerve cells or human skin fibroblasts exposed to low-level MMWs [ 55 , 56 , 57 ].

Gene expression

Some studies have investigated whether low-level MMWs can influence gene expression. Le Queument et al. examined a multitude of genes using microarray analyses and reported transient expression changes in five of them. However, the authors concluded that these results were extremely minor, especially when compared with studies using microarrays to study known pollutants [ 58 ]. Studies by a French research group have examined the effect of MMWs on stress sensitive genes, stress sensitive gene promotors and chaperone proteins in human glial cell lines. In two studies, glial cells were exposed to low-level MMWs and there was no observed modification in the expression of stress sensitive gene promotors when compared with sham exposed cells [ 59 , 60 , 61 ]. Further, glial cells were examined for the expression of the chaperone protein clusterin (CLU) and heat shock protein HSP70. These proteins are activated in times of cellular stress to maintain protein functions and help with the repair process [ 60 ]. There was no observed modification in gene expression of the chaperone proteins. Other studies have examined the endoplasmic reticulum of glial cells exposed to MMWs [ 62 , 63 ]. The endoplasmic reticulum is the site of synthesis and folding of secreted proteins and has been shown to be sensitive to environmental insults [ 62 ]. The authors reported that there was no elevation in mRNA expression levels of endoplasmic reticulum specific chaperone proteins. Studies of stress sensitive genes in glial cells have consistently shown no modification due to low-level MMW exposure [ 59 , 60 , 61 , 62 , 63 ].

Belyaev and co-authors have studied a possible resonance effect of low-level MMWs primarily on Escherichia Coli (E. coli) cells and cultures. The Belyaev research group reported that the resonance effect of MMWs can change the conformation state of chromosomal DNA complexes [ 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 ]; however, most of these experiments were not temperature controlled. This resonance effect was not supported by earlier experiments on a number of different cell types conducted by Gandhi et al. and Bush et al. [ 75 , 76 ].

The results of Belyaev and co-workers have primarily been based on evidence from the anomalous viscosity time dependence (AVTD) method [ 77 ]. The research group argued that changes in the AVTD curve can indicate changes to the DNA conformation state and DNA-protein bonds. Belyaev and co-workers have reported in a number of studies that differences in the AVTD curve were dependent on several parameter including MMW characteristics (frequency, exposure level, and polarisation), cellular concentration and cell growth rate [ 69 , 71 , 72 , 73 , 74 ]. In some of the Belyaev studies E. coli were pre-exposed to X-rays, which was reported to change the AVTD curve; however, if the cells were then exposed to MMWs there was no longer a change in the AVTD curve [ 64 , 65 , 66 , 67 ]. The authors suggested that exposure to MMWs increased the rate of recovery in bacterial cells previously exposed to ionising radiation. The Belyaev group also used rat thymocytes in another study and they concluded that the results closely paralleled those found in E. coli cells [ 67 ]. The studies on the DNA conformation state change relied heavily on the AVTD method that has only been used by the Balyaev group and has not been independently validated [ 78 ].

Cell signalling and electrical activity

Studies examining effects of low-level MMWs on cell signalling have mainly involved MMW exposure to nervous system tissue of various animals. An in vivo study on rats recorded extracellular background electrical spike activity from neurons in the supraoptic nucleus of the hypothalamus after MMW exposure [ 79 ]. The study reported that there were changes in inter-spike interval and spike activity in the cells of exposed animals when compared with controls. There was also a mixture of significant shifts in neuron population proportions and spike frequency. The effect on the regularity of neuron spike activity was greater at higher frequencies. An in vitro study on rat cortical tissue slices reported that neuron firing rates decreased in half of the samples exposed to low-level MMWs [ 80 ]. The width of the signals was also decreased but all effects were short lived. The observed changes were not consistent between the two studies, but this could be a consequence of different brain regions being studied.

In vitro experiments by a Japanese research group conducted on crayfish exposed the dissected optical components and brain to MMWs [ 81 , 82 ]. Munemori and Ikeda reported that there was no significant change in the inter-spike intervals or amplitude of spontaneous discharges [ 81 ]. However, there was a change in the distribution of inter-spike intervals where the initial standard deviation decreased and then restored in a short time to a rhythm comparable to the control. A follow-up study on the same tissues and a wide range of exposure levels (many above the ICNIRP limits) reported similar results with the distribution of spike intervals decreasing with increasing exposure level [ 82 ]. These results on action potentials in crayfish tissue have not been independently investigated.

Mixed results were reported in experiments conducted by a US research group on sciatic frog nerve preparations. These studies applied electrical stimulation to the nerve and examined the effect of MMWs on the compound action potentials (CAPs) conductivity through the neurological tissue fibre. Pakhomov et al. found a reduction in CAP latency accompanied by an amplitude increase for MMWs above the ICNIRP limits but not for low-level MMWs [ 83 ]. However, in two follow-up studies, Pakhomov et al. reported that the attenuation in amplitude of test CAPs caused by high-rate stimulus was significantly reduced to the same magnitude at various MMW exposure levels [ 84 , 85 ]. In all of these studies, the observed effect on the CAPs was temporal and reversible, but there were implications of a frequency specific resonance interaction with the nervous tissue. These results on action potentials in frog sciatic nerves have not been investigated by others.

Other common experimental systems involved low-level MMW exposure to isolated ganglia of leeches. Pikov and Siegel reported that there was a decrease in the firing rate in one of the tested neurons and, through the measurement of input resistance in an inserted electrode, there was a transient dose-dependent change in membrane permeability [ 86 ]. However, Romanenko et al. found that low-level MMWs did not cause suppression of neuron firing rate [ 87 ]. Further experiments by Romanenko et al. reported that MMWs at the ICNIRP public exposure limit and above reported similar action potential firing rate suppression [ 88 ]. Significant differences were reported between MMW effects and effects due to an equivalent rise in temperature caused by heating the bathing solution by conventional means.

Membrane effects

Studies examining membrane interactions with low-level MMWs have all been conducted at frequencies above 40 GHz in in vitro experiments. A number of studies investigated membrane phase transitions involving exposure to a range of phospholipid vesicles prepared to mimic biological cell membranes. One group of studies by an Italian research group reported effects on membrane hydration dynamics and phase transition [ 89 , 90 , 91 ]. Observations included transition delays from the gel to liquid phase or vice versa when compared with sham exposures maintained at the same temperature; the effect was reversed after exposure. These reported changes remain unconfirmed by independent groups.

A number of studies investigated membrane permeability. One study focussed on Ca 2+ activated K + channels on the membrane surface of cultured kidney cells of African Green Marmosets [ 92 ]. The study reported modifications to the Hill coefficient and apparent affinity of the Ca 2+ by the K + channels. Another study reported that the effectiveness of a chemical to supress membrane permeability in the gap junction was transiently reduced when the cells were exposed to MMWs [ 93 , 94 ]. Two studies by one research group reported increases in the movement of molecules into skin cells during MMW exposure and suggested this indicates increased cell membrane permeability [ 21 , 91 ]. Permeability changes based on membrane pressure differences were also investigated in relation to phospholipid organisation [ 95 ]. Although there was no evidence of effects on phospholipid organisation on exposed model membranes, the authors reported a measurable difference in membrane pressure at low exposure levels. Another study reported neuron shrinkage and dehydration of brain tissues [ 96 ]. The study reported this was due to influences of low-level MMWs on the cellular bathing medium and intracellular water. Further, the authors suggested this influence of MMWs may have led to formation of unknown messengers, which are able to modulate brain cell hydration. A study using an artificial axon system consisting of a network of cells containing aqueous phospholipid vesicles reported permeability changes with exposure to MMWs by measuring K + efflux [ 97 ]. In this case, the authors emphasised limitations in applying this model to processes within a living organism. The varied effects of low-level MMWs on membrane permeability lack replication.

Other studies have examined the shape or size of vesicles to determine possible effects on membrane permeability. Ramundo-Orlando et al., reported effects on the shape of giant unilamellar vesicles (GUVs), specifically elongation, attributed to permeability changes [ 98 ]. However, another study reported that only smaller diameter vesicles demonstrated a statistically significant change when exposed to MMWs [ 99 ]. A study by Cosentino et al. examined the effect of MMWs on the size distributions of both large unilamellar vesicles (LUVs) and GUVs in in vitro preparations [ 100 ]. It was reported that size distribution was only affected when the vesicles were under osmotic stress, resulting in a statistically significant reduction in their size. In this case, the effect was attributed to dehydration as a result of membrane permeability changes. There is, generally, lack of replication on physical changes to phospholipid vesicles due to low-level MMWs.

Studies on E. coli and E. hirae cultures have reported resonance effects on membrane proteins and phospholipid constituents or within the media suspension [ 39 , 40 , 41 , 42 ]. These studies observed cell proliferation effects such as changes to cell growth rate, viability and lag phase duration. These effects were reported to be more pronounced at specific MMW frequencies. The authors suggested this could be due to a resonance effect on the cell membrane or the suspension medium. Torgomyan et al. and Hovnanyan et al. reported similar changes to proliferation that they attributed to changes in membrane permeability from MMW exposure [ 43 , 45 ]. These experiments were all conducted by an Armenian research group and have not been replicated by others.

Other effects

A number of studies have reported on the experimental results of other effects. Reproductive effects were examined in three studies on mice, rats and human spermatozoa. An in vivo study on mice exposed to low-level MMWs reported that spermatogonial cells had significantly more metaphase translocation disturbances than controls and an increased number of cells with unpaired chromosomes [ 101 ]. Another in vivo study on rats reported increased morphological abnormalities to spermatozoa following exposure, however, there was no statistical analysis presented [ 102 ]. Conversely, an in vitro study on human spermatozoa reported that there was an increase in motility after a short time of exposure to MMWs with no changes in membrane integrity and no generation of apoptosis [ 103 ]. All three of these studies looked at different effects on spermatozoa making it difficult to make an overall conclusion. A further two studies exposed rats to MMWs and examined their sperm for indicators of ROS production. One study reported both increases and decreases in enzymes that control the build-up of ROS [ 104 ]. The other study reported a decrease in the activity of histone kinase and an increase in ROS [ 105 ]. Both studies had low animal numbers (six animals exposed) and these results have not been independently replicated.

Immune function was also examined in a limited number of studies focussing on the effects of low-level MMWs on antigens and antibody systems. Three studies by a Russian research group that exposed neutrophils to MMWs reported frequency dependant changes in ROS production [ 106 , 107 , 108 ]. Another study reported a statistically significant decrease in antigen binding to antibodies when exposed to MMWs [ 109 ]; the study also reported that exposure decreased the stability of previously formed antigen–antibody complexes.

The effect on fatty acid composition in mice exposed to MMWs has been examined by a Russian research group using a number of experimental methods [ 110 , 111 , 112 ]. One study that exposed mice afflicted with an inflammatory condition to low-level MMWs reported no change in the fatty acid concentrations in the blood plasma. However, there was a significant increase in the omega-3 and omega-6 polyunsaturated fatty acid content of the thymus [ 110 ]. Another study exposed tumour-bearing mice and reported that monounsaturated fatty acids decreased and polyunsaturated fatty acids increased in both the thymus and tumour tissue. These changes resulted in fatty acid composition of the thymus tissue more closely resembling that of the healthy control animals [ 111 ]. The authors also examined the effect of exposure to X-rays of healthy mice, which was reported to reduce the total weight of the thymus. However, when the thymus was exposed to MMWs before or after exposure to X-rays, the fatty acid content was restored and was no longer significantly different from controls [ 112 ]. Overall, the authors reported a potential protective effect of MMWs on the recovery of fatty acids, however, all the results came from the same research group with a lack of replication from others.

Physiological effects were examined by a study conducted on mice exposed to WWMs to assess the safety of police radar [ 113 ]. The authors reported no statistically significant changes in the physiological parameters tested, which included body mass and temperature, peripheral blood and the mass and cellular composition, and number of cells in several important organs. Another study exposing human volunteers to low-level MMWs specifically examined cardiovascular function of exposed and sham exposed groups by electrocardiogram (ECG) and atrioventricular conduction velocity derivation [ 114 ]. This study reported that there were no significant differences in the physiological indicators assessed in test subjects.

Other individual studies have looked at various other effects. An early study reported differences in the attenuation of MMWs at specific frequencies in healthy and tumour cells [ 115 ]. Another early study reported no effect in the morphology of BHK-21/C13 cell cultures when exposed to low-level MMWs; the study did report morphological changes at higher levels, which were related to heating [ 116 ]. One study examined whether low-level MMWs induced cancer promotion in leukaemia and Lewis tumour cell grafted mice. The study reported no statistically significant growth promotion in either of the grafted cancer cell types [ 117 ]. Another study looked at the activity of gamma-glutamyl transpeptidase enzyme in rats after treatment with hydrocortisone and exposure to MMWs [ 118 ]. The study reported no effects at exposures below the ICNIRP limit, however, at levels above authors reported a range of effects. Another study exposed saline liquid solutions to continuous low and high level MMWs and reported temperature oscillations within the liquid medium but lacked a statistical analysis [ 119 ]. Another study reported that low-level MMWs decrease the mobility of the protozoa S. ambiguum offspring [ 120 ]. None of the reported effects in all of these other studies have been investigated elsewhere.

Epidemiological studies

There are no epidemiological studies that have directly investigated 5 G and potential health effects. There are however epidemiological studies that have looked at occupational exposure to radar, which could potentially include the frequency range from 6 to 300 GHz. Epidemiological studies on radar were included as they represent occupational exposure below the ICNIRP guidelines. The review included 31 epidemiological studies (8 cohort, 13 case-control, 9 cross-sectional and 1 meta-analysis) that investigated exposure to radar and various health outcomes including cancer at different sites, effects on reproduction and other diseases. The risk estimates as well as limitations of the epidemiological studies are shown in Table  7 .

Three large cohort studies investigated mortality in military personnel with potential exposure to MMWs from radar. Studies reporting on over 40-year follow-up of US navy veterans of the Korean War found that radar exposure had little effect on all-cause or cancer mortality with the second study reporting risk estimates below unity [ 121 , 122 ]. Similarly, in a 40-year follow-up of Belgian military radar operators, there was no statistically significant increase in all-cause mortality [ 123 , 124 ]; the study did, however, find a small increase in cancer mortality. More recently in a 25-year follow-up of military personnel who served in the French Navy, there was no increase in all-cause or cancer mortality for personnel exposed to radar [ 125 ]. The main limitation in the cohort studies was the lack of individual levels of RF exposure with most studies based on job-title. Comparisons were made between occupations with presumed high exposure to RF fields and other occupations with presumed lower exposure. This type of non-differential misclassification in dichotomous exposure assessment is associated mostly with an effect measure biased towards a null effect if there is a true effect of RF fields. If there is no true effect of RF fields, non-differential exposure misclassification will not bias the effect estimate (which will be close to the null value, but may vary because of random error). The military personnel in these studies were compared with the general population and this ‘healthy worker effect’ presents possible bias since military personnel are on average in better health than the general population; the healthy worker effect tends to underestimate the risk. The cohort studies also lacked information on possible confounding factors including other occupational exposures such as chemicals and lifestyle factors such as smoking.

Several epidemiological studies have specifically investigated radar exposure and testicular cancer. In a case-control study where most of the subjects were selected from military hospitals in Washington DC, USA, Hayes et al. found no increased risk between exposure to radar and testicular cancer [ 126 ]; exposure to radar was self-reported and thus subject to misclassification. In this study, the misclassification was likely non-differential, biasing the result towards the null. Davis and Mostofi reported a cluster of testicular cancer within a small cohort of 340 police officers in Washington State (USA) where the cases routinely used handheld traffic radar guns [ 127 ]; however, exposure was not assessed for the full cohort, which may have overestimated the risk. In a population-based case-control study conducted in Sweden, Hardell et al. did not find a statistically significant association between radar work and testicular cancer; however, the result was based on only five radar workers questioning the validity of this result [ 128 ]. In a larger population-based case control study in Germany, Baumgardt-Elms et al. also reported no association between working near radar units (both self-reported and expert assessed) and testicular cancer [ 129 ]; a limitation of this study was the low participation of identified controls (57%), however, there was no difference compared with the characteristics of the cases so selection bias was unlikely. In the cohort study of US navy veterans previously mentioned exposure to radar was not associated with testicular cancer [ 122 ]; the limitations of this cohort study mentioned earlier may have underestimated the risk. Finally, in a hospital-based case-control study in France, radar workers were also not associated with risk of testicular cancer [ 130 ]; a limitation was the low participation of controls (37%) with a difference in education level between participating and non-participating controls, which may have underestimated this result.

A limited number of studies have investigated radar exposure and brain cancer. In a nested case-control study within a cohort of male US Air Force personnel, Grayson reported a small association between brain cancer and RF exposure, which included radar [ 131 ]; no potential confounders were included in the analysis, which may have overestimated the result. However, in a case-control study of personnel in the Brazilian Navy, Santana et al. reported no association between naval occupations likely to be exposed to radar and brain cancer [ 132 ]; the small number of cases and lack of diagnosis confirmation may have biased the results towards the null. All of the cohort studies on military personnel previously mentioned also examined brain cancer mortality and found no association with exposure to radar [ 122 , 124 , 125 ].

A limited number of studies have investigated radar exposure and ocular cancer. Holly et al. in a population-based case-control study in the US reported an association between self-reported exposure to radar or microwaves and uveal melanoma [ 133 ]; the study investigated many different exposures and the result is prone to multiple testing. In another case-control study, which used both hospital and population controls, Stang et al. did not find an association between self-reported exposure to radar and uveal melanoma [ 134 ]; a high non-response in the population controls (52%) and exposure misclassification may have underestimated this result. The cohort studies of the Belgian military and French navy also found no association between exposure to radar and ocular cancer [ 124 , 125 ].

A few other studies have examined the potential association between radar and other cancers. In a hospital-based case-control study in Italy, La Vecchia investigated 14 occupational agents and risk of bladder cancer and found no association with radar, although no risk estimate was reported [ 135 ]; non-differential self-reporting of exposure may have underestimated this finding if there is a true effect. Finkelstein found an increased risk for melanoma in a large cohort of Ontario police officers exposed to traffic radar and followed for 31 years [ 136 ]; there was significant loss to follow up which may have biased this result in either direction. Finkelstein found no statistically significant associations with other types of cancer and the study reported a statistically significant risk estimate just below unity for all cancers, which is reflective of the healthy worker effect [ 136 ]. In a large population-based case-control study in France, Fabbro-Peray et al. investigated a large number of occupational and environmental risk factors in relation to non-Hodgkin lymphoma and found no association with radar operators based on job-title; however, the result was based on a small number of radar operators [ 137 ]. The cohort studies on military personnel did not find statistically significant associations between exposure to radar and other cancers [ 122 , 124 , 125 ].

Variani et al. conducted a recent systematic review and meta-analysis investigating occupational exposure to radar and cancer risk [ 138 ]. The meta-analysis included three cohort studies [ 122 , 124 , 125 ] and three case-control studies [ 129 , 130 , 131 ] for a total sample size of 53,000 subjects. The meta-analysis reported a decrease in cancer risk for workers exposed to radar but noted the small number of studies included with significant heterogeneity between the studies.

Apart from cancer, a number of epidemiological studies have investigated radar exposure and reproductive outcomes. Two early studies on military personnel in the US [ 139 ] and Denmark [ 140 ] reported differences in semen parameters between personnel using radar and personnel on other duty assignments; these studies included only volunteers with potential fertility concerns and are prone to bias. A further volunteer study on US military personnel did not find a difference in semen parameters in a similar comparison [ 141 ]; in general these type of cross-sectional investigations on volunteers provide limited evidence on possible risk. In a case-control study of personnel in the French military, Velez de la Calle et al. reported no association between exposure to radar and male infertility [ 142 ]; non-differential self-reporting of exposure may have underestimated this finding if there is a true effect. In two separate cross-sectional studies of personnel in the Norwegian navy, Baste et al. and Møllerløkken et al. reported an association between exposure to radar and male infertility, but there has been no follow up cohort or case control studies to confirm these results [ 143 , 144 ].

Again considering reproduction, a number of studies investigated pregnancy and offspring outcomes. In a population-based case-control study conducted in the US and Canada, De Roos et al. found no statistically significant association between parental occupational exposure to radar and neuroblastoma in offspring; however, the result was based on a small number of cases and controls exposed to radar [ 145 ]. In another cross-sectional study of the Norwegian navy, Mageroy et al. reported a higher risk of congenital anomalies in the offspring of personnel who were exposed to radar; the study found positive associations with a large number of other chemical and physical exposures, but the study involved multiple comparisons so is prone to over-interpretation [ 146 ]. Finally, a number of pregnancy outcomes were investigated in a cohort study of Norwegian navy personnel enlisted between 1950 and 2004 [ 147 ]. The study reported an increase in perinatal mortality for parental service aboard fast patrol boats during a short period (3 months); exposure to radar was one of many possible exposures when serving on fast patrol boats and the result is prone to multiple testing. No associations were found between long-term exposure and any pregnancy outcomes.

There is limited research investigating exposure to radar and other diseases. In a large case-control study of US military veterans investigating a range of risk factors and amyotrophic lateral sclerosis, Beard et al. did not find a statistically significant association with radar [ 148 ]; the study reported a likely under-ascertainment of non-exposed cases, which may have biased the result away from the null. The cohort studies on military personnel did not find statistically significant associations between exposure to radar and other diseases [ 122 , 124 , 125 ].

A number of observational studies have investigated outcomes measured on volunteers in the laboratory. They are categorised as epidemiological studies because exposure to radar was not based on provocation. These studies investigated genotoxicity [ 149 ], oxidative stress [ 149 ], cognitive effects [ 150 ] and endocrine function [ 151 ]; the studies generally reported positive associations with radar. These volunteer studies did not sample from a defined population and are prone to bias [ 152 ].

The experimental studies investigating exposure to MMWs at levels below the ICNIRP occupational limits have looked at a variety of biological effects. Genotoxicity was mainly examined by using comet assays of exposed cells. This approach has consistently found no evidence of DNA damage in skin cells in well-designed studies. However, animal studies conducted by one research group reported DNA strand breaks and changes in enzymes that control the build-up of ROS, noting that these studies had low animal numbers (six animals exposed); these results have not been independently replicated. Studies have also investigated other indications of genotoxicity including chromosome aberrations, micro-nucleation and spindle disturbances. The methods used to investigate these indicators have generally been rigorous; however, the studies have reported contradictory results. Two studies by a Russian research group have also reported indicators of DNA damage in bacteria, however, these results have not been verified by other investigators.

The studies of the effect of MMWs on cell proliferation primarily focused on bacteria, yeast cells and tumour cells. Studies of bacteria were mainly from an Armenian research group that reported a reduction in the bacterial growth rate of exposed E. coli cells at different MMW frequencies; however, the studies suffered from inadequate dosimetry and temperature control and heating due to high RF energy deposition may have contributed to the results. Other authors have reported no effect of MMWs on E. coli cell growth rate. The results on cell proliferation of yeast exposed to MMWs were also contradictory. An Italian research group that has conducted the majority of the studies on tumour cells reported either a reduction or no change in the proliferation of exposed cells; however, these studies also suffered from inadequate dosimetry and temperature control.

The studies on gene expression mainly examined two different indicators, expression of stress sensitive genes and chaperone proteins and the occurrence of a resonance effect in cells to explain DNA conformation state changes. Most studies reported no effect of low-level MMWs on the expression of stress sensitive genes or chaperone proteins using a range of experimental methods to confirm these results; noting that these studies did not use blinding so experimental bias cannot be excluded from the results. A number of studies from a Russian research group reported a resonance effect of MMWs, which they propose can change the conformation state of chromosomal DNA complexes. Their results relied heavily on the AVTD method for testing changes in the DNA conformation state, however, the biological relevance of results obtained through the AVTD method has not been independently validated.

Studies on cell signalling and electrical activity reported a range of different outcomes including increases or decreases in signal amplitude and changes in signal rhythm, with no consistent effect noting the lack of blinding in most of the studies. Further, temperature contributions could not be eliminated from the studies and in some cases thermal interactions by conventional heating were studied and found to differ from the MMW effects. The results from some studies were based on small sample sizes, some being confined to a single specimen, or by observed effects only occurring in a small number of the samples tested. Overall, the reported electrical activity effects could not be dismissed as being within normal variability. This is indicated by studies reporting the restoration of normal function within a short time during ongoing exposure. In this case there is no implication of an expected negative health outcome.

Studies on membrane effects examined changes in membrane properties and permeability. Some studies observed changes in transitions from liquid to gel phase or vice versa and the authors implied that MMWs influenced cell hydration, however the statistical methods used in these studies were not described so it is difficult to examine the validity of these results. Other studies observing membrane properties in artificial cell suspensions and dissected tissue reported changes in vesicle shape, reduced cell volume and morphological changes although most of these studies suffered from various methodological problems including poor temperature control and no blinding. Experiments on bacteria and yeast were conducted by the same research group reporting changes in membrane permeability, which was attributed to cell proliferation effects, however, the studies suffered from inadequate dosimetry and temperature control. Overall, although there were a variety of membrane bioeffects reported, these have not been independently replicated.

The limited number of studies on a number of other effects from exposure to MMWs below the ICNIRP limits generally reported little to no consistent effects. The single in vivo study on cancer promotion did not find an effect although the study did not include sham controls. Effects on reproduction were contradictory that may have been influenced by opposing objectives of examining adverse health effects or infertility treatment. Further, the only study on human sperm found no effects of low-level MMWs. The studies on reproduction suffered from inadequate dosimetry and temperature control, and since sperm is sensitive to temperature, the effect of heating due to high RF energy deposition may have contributed to the studies showing an effect. A number of studies from two research groups reported effects on ROS production in relation to reproduction and immune function; the in vivo studies had low animal numbers (six animals per exposure) and the in vitro studies generally had inadequate dosimetry and temperature control. Studies on fatty acid composition and physiological indicators did not generally show any effects; poor temperature control was also a problem in the majority of these studies. A number of other studies investigating various other biological effects reported mixed results.

Although a range of bioeffects have been reported in many of the experimental studies, the results were generally not independently reproduced. Approximately half of the studies were from just five laboratories and several studies represented a collaboration between one or more laboratories. The exposure characteristics varied considerably among the different studies with studies showing the highest effect size clustered around a PD of approximately 1 W/m 2 . The meta-analysis of the experimental studies in our companion paper [ 9 ] showed that there was no dose-response relationship between the exposure (either PD or SAR) and the effect size. In fact, studies with a higher exposure tended to show a lower effect size, which is counterfactual. Most of the studies showing a large effect size were conducted in the frequency range around 40–55 GHz, representing investigations into the use of MMWs for therapeutic purposes, rather than deleterious health consequences. Future experimental research would benefit from investigating bioeffects at the specific frequency range of the next stage of the 5 G network roll-out in the range 26–28 GHz. Mobile communications beyond the 5 G network plan to use frequencies higher than 30 GHz so research across the MMW band is relevant.

An investigation into the methods of the experimental studies showed that the majority of studies were lacking in a number of quality criteria including proper attention to dosimetry, incorporating positive controls, using blind evaluation or accurately measuring or controlling the temperature of the biological system being tested. Our meta-analysis showed that the bulk of the studies had a quality score lower than 2 out of a possible 5, with only one study achieving a maximum quality score of 5 [ 9 ]. The meta-analysis further showed that studies with a low quality score were more likely to show a greater effect. Future research should pay careful attention to the experimental design to reduce possible sources of artefact.

The experimental studies included in this review reported PDs below the ICNIRP exposure limits. Many of the authors suggested that the resulting biological effects may be related to non-thermal mechanisms. However, as is shown in our meta-analysis, data from these studies should be treated with caution because the estimated SAR values in many of the studies were much higher than the ICNIRP SAR limits [ 9 ]. SAR values much higher than the ICNIRP guidelines are certainly capable of producing significant temperature rise and are far beyond the levels expected for 5 G telecommunication devices [ 1 ]. Future research into the low-level effects of MMWs should pay particular attention to appropriate temperature control in order to avoid possible heating effects.

Although a systematic review of experimental studies was not conducted, this paper presents a critical appraisal of study design and quality of all available studies into the bioeffects of low level MMWs. The conclusions from the review of experimental studies are supported by a meta-analysis in our companion paper [ 9 ]. Given the low-quality methods of the majority of the experimental studies we infer that a systematic review of different bioeffects is not possible at present. Our review includes recommendations for future experimental research. A search of the available literature showed a further 44 non-English papers that were not included in our review. Although the non-English papers may have some important results it is noted that the majority are from research groups that have published English papers that are included in our review.

The epidemiological studies on MMW exposure from radar that has a similar frequency range to that of 5 G and exposure levels below the ICNIRP occupational limits in most situations, provided little evidence of an association with any adverse health effects. Only a small number of studies reported positive associations with various methodological issues such as risk of bias, confounding and multiple testing questioning the result. The three large cohort studies of military personnel exposed to radar in particular did not generally show an association with cancer or other diseases. A key concern across all the epidemiological studies was the quality of exposure assessment. Various challenges such as variability in complex occupational environments that also include other co-exposures, retrospective estimation of exposure and an appropriate exposure metric remain central in studies of this nature [ 153 ]. Exposure in most of the epidemiological studies was self-reported or based on job-title, which may not necessarily be an adequate proxy for exposure to RF fields above 6 GHz. Some studies improved on exposure assessment by using expert assessment and job-exposure matrices, however, the possibility of exposure misclassification is not eliminated. Another limitation in many of the studies was the poor assessment of possible confounding including other occupational exposures and lifestyle factors. It should also be noted that close proximity to certain very powerful radar units could have exceeded the ICNIRP occupational limits, therefore the reported effects especially related to reproductive outcomes could potentially be related to heating.

Given that wireless communications have only recently started to use RF frequencies above 6 GHz there are no epidemiological studies investigating 5 G directly as yet. Some previous epidemiological studies have reported a possible weak association between mobile phone use (from older networks using frequencies below 6 GHz) and brain cancer [ 11 ]. However, methodological limitations in these studies prevent conclusions of causality being drawn from the observations [ 152 ]. Recent investigations have not shown an increase in the incidence of brain cancer in the population that can be attributed to mobile phone use [ 154 , 155 ]. Future epidemiological research should continue to monitor long-term health effects in the population related to wireless telecommunications.

The review of experimental studies provided no confirmed evidence that low-level MMWs are associated with biological effects relevant to human health. Many of the studies reporting effects came from the same research groups and the results have not been independently reproduced. The majority of the studies employed low quality methods of exposure assessment and control so the possibility of experimental artefact cannot be excluded. Further, many of the effects reported may have been related to heating from high RF energy deposition so the assertion of a ‘low-level’ effect is questionable in many of the studies. Future studies into the low-level effects of MMWs should improve the experimental design with particular attention to dosimetry and temperature control. The results from epidemiological studies presented little evidence of an association between low-level MMWs and any adverse health effects. Future epidemiological research would benefit from specific investigation on the impact of 5 G and future telecommunication technologies.

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This work was supported by the Australian Government’s Electromagnetic Energy Program. This work was also partly supported by National Health and Medical Research Council grant no. 1042464. 

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Karipidis, K., Mate, R., Urban, D. et al. 5G mobile networks and health—a state-of-the-science review of the research into low-level RF fields above 6 GHz. J Expo Sci Environ Epidemiol 31 , 585–605 (2021). https://doi.org/10.1038/s41370-021-00297-6

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Received : 30 July 2020

Revised : 23 December 2020

Accepted : 21 January 2021

Published : 16 March 2021

Issue Date : July 2021

DOI : https://doi.org/10.1038/s41370-021-00297-6

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Wireless technology is an environmental stressor requiring new understanding and approaches in health care

Julie e. mccredden.

1 Oceania Radiofrequency Scientific Advisory Association (ORSAA), Brisbane, QLD, Australia

Steven Weller

2 Centre for Environmental and Population Health, School of Medicine and Dentistry, Griffith University, Brisbane, QLD, Australia

Victor Leach

Associated data.

Electromagnetic signals from everyday wireless technologies are an ever-present environmental stressor, affecting biological systems. In this article, we substantiate this statement based on the weight of evidence from papers collated within the ORSAA database (ODEB), focusing on the biological and health effects of electromagnetic fields and radiation. More specifically, the experiments investigating exposures from real-world devices and the epidemiology studies examining the effects of living near mobile phone base stations were extracted from ODEB and the number of papers showing effects was compared with the number showing no effects. The results showed that two-thirds of the experimental and epidemiological papers found significant biological effects. The breadth of biological and health categories where effects have been found was subsequently explored, revealing hundreds of papers showing fundamental biological processes that are impacted, such as protein damage, biochemical changes and oxidative stress. This understanding is targeted toward health professionals and policy makers who have not been exposed to this issue during training. To inform this readership, some of the major biological effect categories and plausible mechanisms of action from the reviewed literature are described. Also presented are a set of best practice guidelines for treating patients affected by electromagnetic exposures and for using technology safely in health care settings. In conclusion, there is an extensive evidence base revealing that significant stress to human biological systems is being imposed by exposure to everyday wireless communication devices and supporting infrastructure. This evidence is compelling enough to warrant an update in medical education and practice.

Introduction

Environmental illness often comes as a surprise to scientists and doctors alike. Environmental causes for human maladies are not always featured in formal training, yet they have accompanied many man-made innovations, from perfume and paint to petrol and plastics ( 1 ). It should not be surprising then that the modern world, saturated with technology, would impose effects on human biological systems, which are built from electrochemical processes. Electromagnetic fields and electromagnetic radiation, both natural and manmade, permeate the modern world. In particular, communications technology has become ubiquitous, with devices and transmitters placed in workplaces, homes, schools, hospitals and surrounding suburbs. The frequencies for relaying communications signals are collectively referred to as “radiofrequency” (RF). Examples of everyday technologies that use radiofrequencies include Wi-Fi routers, mobile phones, cordless phones, suburban towers, masts and panels on buildings (including hospitals), Bluetooth devices, smart meters, Fitbits, smart watches, baby monitors, game consoles and smart diapers (nappies).

The evidence base regarding the effects of ever-present electromagnetic pollution on health indicates that it acts like a stressor, placing an increasing burden on human biological systems ( 2 , 3 ). However, while there have been some positive shifts in recent WHO Health topics, incorporating the effects of water and air pollution, endocrine disrupters, mercury and climate change, there has been very little focus on investigating electromagnetic pollution as an environmental stressor ( 4 ).

While much of the medical world remains ignorant regarding this environmental stressor, patients suffer ( 5 ). Such has been the clinical experience of one of the authors of this paper. People with hypersensitivity to electromagnetic fields may present to hospitals or clinics with an array of complaints that may or may not be based on their underlying condition, e.g., a bone fracture or a heart condition. While waiting, or during treatment, they may ask to be separated from mobile or cordless phones. Health care workers, not having heard of the condition of electromagnetic hypersensitivity or not having an understanding of the biological effects that are associated with electromagnetic fields, can find such requests strange or confusing and are unable to respond appropriately ( 6 ). This unmet need in care settings has motivated this paper, aimed at assisting the broader health profession with an understanding of how electromagnetic fields can affect human biology and providing guidance on how to respond to electrosensitive patients.

There also exists a level of ignorance surrounding this issue across the radiation protection profession. As a retired radiation protection practitioner, one of the authors of this paper has firsthand experience of how the busy daily working life in radiation protection involves a narrow focus on sources of ionizing radiation, with very little involvement, if any, on non-ionizing radiation devices that emit RF signals. Furthermore, if the need to investigate RF exposure arises, professionals seek advice from groups like the International Commission on Non-Ionizing Radiation Protection (ICNIRP), trusting that these bodies are honestly applying the ethical principles and risk reduction philosophies established by the International Commission on Radiation Protection (ICRP). The section on Public Safety Issues below discusses the unfortunate lack of precaution associated with RF technologies.

Despite the lack of official recognition, strong concerns for health and safety relating to radiofrequency emissions have recently entered the public arena. For example, in 2020, the Canton of Geneva placed a 3-year moratorium on fifth generation (5G) wireless technology ( 7 ) in response to public concerns and the lack of research into the effects of 5G on health and biodiversity. More recently, the US Court of Appeals for the D.C. Circuit ( 8 ) has ruled that the US Federal Communications Commission (FCC) has been negligent in its role as protector of the public's health over the last two decades by failing to consider the non-cancer evidence regarding adverse health effects and environmental effects of wireless technologies. Given this significant ruling, health care workers need to build an understanding of the RF exposure-induced health effects and their implications for medical practice.

Evidence base

Health clinicians and policy makers must be assured that sound science is behind any claims that RF is an environmental stressor. The first section of this overview paper addresses this need, by summarizing the current scientific and medical evidence base that explores biological harm from everyday devices and wireless infrastructure in the built environment.

The scientific and medical evidence base that explores biological harm from low-level exposures to radiofrequency (i.e., non-thermal effects) was reviewed over a decade ago by a team of independent scientists and public health professionals who compiled The BioInitiative Report ( 9 – 11 ). This report summarized the evidence for an array of biological and health issues, including reduced fertility, neurological and behavioral effects, childhood leukemia, effects on gene and protein expression, and effects on immune function as well as cell stress responses. The 2020 BioInitiative Report update ( 11 ) comprises an extensive set of abstracts, tables, research summaries and the balance of evidence i.e., the number of studies showing effects vs. no effects. [Note: While there was some initial criticism of The BioInitiative Report as being biased and not peer-reviewed, many of the chapters were later published as peer-reviewed publications, e.g., ( 12 ), thereby laying these criticisms to rest].

The Oceania Radiofrequency Scientific Advisory Association (ORSAA) ( 13 ) has developed the world's largest categorized database of scientific studies on the biological and health effects of electromagnetic fields on humans, animals and the environment ( 14 ). The ORSAA Database of EMF Bioeffects (ODEB) ( 14 ) was first established using the entire research database of the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA), and has been continually expanded, developed and refined ever since. ODEB currently comprises over 4,000 peer-reviewed publications (of which, over 2,400 are radiofrequency papers as of May 2022), including early military studies from the 70's, biophysics research from the 80's (before mobile phones) onwards, and a comprehensive collection of experimental and epidemiological research from both industry and independent scientists since 2012.

ODEB is continually being updated; i.e., two primary sources that were used to establish ODEB are now utilized on an ongoing basis for accessing candidate studies pertaining to ELF and RF frequencies. These are the US National Library of Medicine PubMed database and the ARPANSA technical series documentation, along with their EMR monthly literature surveys with reviews. Papers from the EMF-Portal of Rheinisch-Westfälische Technische Hochschule (RWTH) at Aachen University are also included if they pertain to EMF/EMR and health or bioeffect outcomes lower than the official ICNIRP thresholds (see below). This latter database contains many papers pertaining to EMR science that are not relevant to typical day-to-day public exposures, such as medical procedures and applications (ablation and diathermy) and electrical injuries, which are considered off-topic. Furthermore, many of the EMF-Portal papers describe results of exposures from power densities that create well-established heating effects that are protected against by current RF Guidelines and national RF exposure standards. ODEB, on the other hand, is more narrowly focused on studies using RF exposure levels sitting at approximately the ICNIRP exposure limit or below. These levels were chosen because this is where the crucial experiments have been performed to address the pertinent issues of bioeffects occurring at typical everyday public exposure levels and the subsequent appropriateness, or not, of current national RF standards. Articles are not selected for ODEB on the basis of positive bioeffect findings; i.e., there has been no “cherry-picking” of papers for inclusion. A comparison between the EMF-Portal and ODEB was carried out for relevant papers finding strong agreement on the number of studies ( 15 ) for the focus area.

ODEB is a true relational database with extensive search capabilities and is only limited by the categorization field set that is made available. This set is quite comprehensive in that ODEB is searchable by experimental category, biological endpoints, funding type, and many other variables 1

Overall, we believe that the current evidence base regarding the effects of radiofrequency on biological processes is comprehensively represented by the structured collection of research papers in ODEB. The opinions given below are based on the weight of evidence emerging from ODEB and the papers from within this collection that describe effects.

The research papers in ODEB have been classified by ORSAA into major biological and health effects categories. The main categories discussed in the literature and used within ODEB are:

• DNA and cell damage in the brain, blood, body organs, immune and reproductive systems;
• Increased production of free radicals leading to a state of oxidative stress, and resulting in accumulated damage throughout the body;
• Neurodegeneration and blood-brain barrier breaches;
• Changes to neurotransmitter levels and signaling pathways in the brain;
• Damage to sperm and ovaries;
• Endocrine system effects;
• Damage to cellular systems and components such as mitochondria, mast cells and alterations to cellular signaling systems.

Damage to these processes underlies many health conditions.

Papers in ODEB are classified as an “Effect” paper if any one of the end-points reported in experiments within the paper is statistically significant ( p < 0.05). Over two-thirds of the recent UHF (300 MHz-3 GHz) studies in ODEB contain significant effects of radiofrequency on biological systems or health, as described below.

Evidence for biological effects of radiofrequency exposures

Selection criteria.

This overview focuses on papers that use real-world exposure signals from everyday devices and communications infrastructure because our claim is that these technologies are an RF-based environmental stressor on biological processes and as a consequence, on health. Moreover, we claim these effects occur at and below the exposure thresholds set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP; refer to section Public safety issues below). For this overview, papers were selected that were able to test our claims. Selection criteria included (1) relevance, (2) quality of reporting, and (3) quality of experimental design, as explained below. Note that this paper is not intended to be a systematic review; however, the structures contained in ODEB provide a helpful resource for such a review in the future. For example, the flow chart in Supplementary Data Sheet 3 summarizes the selection process used to extract the data used for Figure 1 , using the layout of a Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) flow chart.

The number of selected experimental papers (using real-world signals) within the main bioeffects or health effects categories in ODEB.

Relevant for selection were those papers with stimulus signals in the radiofrequency range 300 kHz to 300 GHz and with exposure intensity levels below the ICNIRP thresholds. The subset of these relevant papers that were epidemiological studies ( n = 251) were all accepted because, by their very nature, they investigate the effects of “real world” signals on residents living near mobile phone towers/base stations. However, there was also a large group of experimental papers that required further filtering. For these, quality in reporting was determined by the rejection of papers that, although relevant, gave a poor description of the signal type used; i.e., of the 1,343 relevant experimental papers in ODEB, 237 were rejected based on poor reporting, leaving 1,106 experimental papers remaining.

The quality of the experimental design was then determined based on whether the experiment used real-world signals instead of simulated signals. This selection criterion was deemed important (i) because the investigation focused on real-world exposures, and (2) because previous studies have noted that real-world signals (e.g., from mobile phones) are more likely to produce experimental biological interference effects than simulated laboratory signals that using synthesized, regular patterns ( 16 ). Even though simulated signals may be easier to control in experimental settings, they do not allow the experimenter to explore the essential factors that seem to cause stronger biological effects. This is possible because real-world devices emit constantly varying signals, to which human psychophysical systems appear to struggle to adapt, or because they contain pulses that elicit greater biological responses when compared to continuous waves of the same frequency ( 17 ). These pertinent factors need to be the focus of future research.

Indeed, the data from ODEB (see Table 1 ) corroborates the above research findings, by showing that the type of signal used: real or simulated, can affect study outcomes. Within the 1,106 relevant experimental papers selected from ODEB using the quality of reporting criteria above, there were proportionally more “Effect” outcomes when the experiments used real-world signals and proportionally more “No Effect” outcomes when simulated signals were used. This relationship between signal type and biological effect outcome was statistically significant ( X 1 2 = 21.2; p < 0.05), indicating that signal type needs to be clearly articulated in reporting because it can potentially bias outcomes. This result also supports our decision to investigate further only the experimental papers that used real-world signals. For these papers, shown in the final column of Table 1 , there was a significantly higher proportion of papers showing effects (79.1%) than those reporting no effects (15.3%).

Outcomes for selected experimental ( in vitro and in vivo ) studies.

Figure 2 illustrates the outcomes for the selected experimental papers compared to the epidemiology papers, showing that there was a similar pattern of more “Effect” papers existing for both study types. However, epidemiology studies have a larger proportion of “Uncertain Effects”. This is probably because epidemiology studies rely on finding a statistical association between increased exposures to base stations and higher numbers of affected people. Subsequently, the results are likely to be influenced by many potential confounders, co-causal factors ( 18 ), and sources of noise. It thus becomes more difficult to find strong effects from one variable amongst the many in such epidemiology studies. For example, because people today are surrounded by ELF and RF fields in everyday life i.e., personal wireless devices, it is difficult to isolate distance from a tower as a separate study variable that can indicate actual exposure levels or even find unexposed controls. Despite these potential weaknesses, epidemiology studies dominate RF research when it comes to exposure of human participants. Figure 2 shows that two-thirds of the relevant epidemiology papers selected from ODEB showed effects associated with increased exposures. Details of the ODEB search results used to construct Figure 2 are given in Supplementary Data Sheet 1 .

The relative numbers of selected experimental and epidemiological papers showing effects, no effects and uncertain effects.

Sufficient evidence to motivate change

Results like those shown in Figure 2 provoke the question: “What constitutes enough evidence to support the claim that RF is an environmental stressor causing biological and health effects?” This issue of sufficient evidence has been explored in great detail in Late Lessons from Early Warnings, Part E: Implications for science and governance . In this report commissioned by the European Union, Gee ( 18 ) explains to all stakeholders that the strength of scientific evidence is not all or nothing; rather, it varies on a scale from very weak to very strong . That is, if the evidence is not yet conclusive, this does not mean there is no important evidence. There can still be sufficient evidence for governments and decision-makers to act so as to protect the health of humans, animals and plants from potential risks. The results shown in Table 1 and Figure 2 make the case for recognizing sufficient evidence exists and subsequently raising RF bioeffects in the environment as an important issue for decision-makers and providers of health policy, prevention and care.

This paper is aimed at those people who are responsible for setting health policy as well as those involved in health care. Given that the data above has established strong evidence, we now present in more detail the types of biological and health effects that have been shown to occur from real-world RF exposures.

Types of effects observed

Figure 1 illustrates the biological effects categories underpinning the Experimental bar chart shown in Figure 2 . The categories and counts in Figure 1 were taken from an ODEB summary page based on a search for the 323 selected experimental “Effect” papers [see Supplementary Data Sheet 3 , part (iii)]. This selection is from papers that use real-world signals in their experimental design. For example, a search in ODEB for experimental papers that satisfied all of the selection criteria and found effects due to Oxidative Stress/ROS/Free radicals resulted in 79 papers, shown as one of the categories in Figure 1 (These Oxidative stress papers are also listed in detail within Supplementary Data Sheet 1 ).

The main narrative of this paper has been drawn from the above weight of evidence, that biological effects from low level everyday radiofrequency exposures exist. The sections below review papers that are illustrative of the main categories of effects found within ODEB; in particular, those with potential implications for human health. However, there are papers contained within ODEB that show no effects. These papers are not presented; rather, it is left to the reader to explore these papers using the online ODEB resource.

Conditions arising from oxidative stress

Oxidative stress is now recognized as an underlying cause of many chronic diseases, such as cardiovascular disease and diabetes, Alzheimer's disease and depression. The Swiss expert research group BERENIS recently reviewed this topic and reported that most animal studies and more than half of the cell studies provided evidence of increased oxidative stress from electromagnetic fields, even in the low-dose range ( 19 ). Health conditions promoted by electromagnetic-induced oxidative stress include allergies and atopic dermatitis, autoimmune diseases such as diabetes, eye conditions, and fertility effects. Papers relating to all these topics can be found by searching ODEB online.

In 2011, The International Agency for Research on Cancer (IARC) classified radiofrequency as a Class 2B, Possible Carcinogen ( 20 ). More recently, the National Toxicology Program (NTP) results in the USA provided “clear” evidence linking radiofrequency exposure to cancer ( 21 , 22 ). The $30M NTP study used exposure scenarios on rats that simulated human mobile phone exposure levels and higher. The results showed that male rats were more likely to develop malignant cardiac schwannomas than the unexposed control group. These rare nerve tumors have been previously linked to heavy cell phone use ( 23 ).

A similar animal experiment using lifetime exposures to low-intensity radiofrequencies equivalent to cell phone base station exposures was performed by the Ramazzini Institute. The same rare nerve tumors found in the NTP study were also found in the Ramazzini study. In light of these combined results, scientists globally have called for a WHO IARC upgrade of radiofrequency to a Class 1, “Known Carcinogen” category ( 24 ). The NTP study was used for a landmark legal case by the Turin Court of appeal ( 25 ), where the court confirmed that acoustic neuroma (vestibular schwannomas) can be caused by the occupational use of a mobile phone and that sufficient scientific evidence exists supporting this causal link.

The vulnerable brain and children

In our technology-driven world, the human brain is constantly being subjected to everyday radiofrequency signals that cause structural and functional damage; e.g., to the hippocampus ( 26 ), the blood-brain barrier ( 27 ), mitochondrial energy metabolism ( 28 ) and neurotransmitters ( 29 ), which lead to negative consequences such as reduced spatial memory, unexplained headaches, reduced sleep performance, and neurological, cognitive and emotional disorders ( 29 – 32 ). Children's brains are especially vulnerable to damage and dysfunction because their skulls are thinner, and their brains absorb more radiation ( 33 , 34 ). Children are now being exposed to radiofrequency from before conception. Based on a 10-year longitudinal study showing declines in an array of psychophysiological indicators, Grigoriev and Khorseva ( 35 ) concluded that children are a “group at risk” from mobile phone exposures. Children are now starting to appear in the long-term mobile phone user group (>10 years), which is the group most likely to be at risk of developing brain tumors ( 36 , 37 ). Carpenter has warned that the cost of doing nothing may significantly harm a generation of young people who carry their mobile phones close to their bodies for many hours a day ( 38 ).

Electromagnetic hypersensitivity: The canaries in the coal-mine

Some individuals suffer noticeable symptoms when exposed to radiofrequency or electromagnetic fields from telecommunications systems, electronic devices or electrical wiring. These symptoms are highly varied yet relate to classical symptoms of “microwave sickness” ( 39 ) which sufferers attribute to exposures to radiofrequency emitting devices or cell towers. These symptoms include headaches (not the typical headache), head pressure, chest pressure, dysesthesia (skin irritation) and paraesthesia (tingling, prickling, burning sensations), insomnia, concentration difficulties, tinnitus (ringing in the ears), memory issues, dizziness, heart problems such as arrhythmia/palpitations/tachycardia, anxiety, joint pain, chronic fatigue, muscle pain and dermatological effects such as rashes ( 40 – 42 ). “Electromagnetic hypersensitivity” (EHS) is the common term used to describe this condition. It is classified in the International Classification for Diseases, ICD-10, under category W90: Adverse health effects of exposure to RF-EMR ( 43 ). The WHO recognizes electromagnetic hypersensitivity as “idiopathic environmental intolerance” ( 44 ) but not the cause, and in Sweden it is recognized as a functional impairment ( 45 ).

Before mobile phones existed, Frey ( 46 ) found robust evidence that humans have a sensory system tuned to microwave frequencies. Moreover, these frequencies induced blood-brain barrier penetration and altered the brain's opiate-dopamine system, likely causing the headaches reported by Frey's research participants ( 47 ). Frey concluded that a person reporting headaches from mobile phone exposures might be a canary in the coal mine warning of other biological effects [47, p. 102].

More recently, medical researchers have found further evidence to establish electromagnetic hypersensitivity as a real condition:

• Environmental factors implicated : Electromagnetic hypersensitivity often occurs after prolonged exposures to electromagnetic fields at work or after medical examinations using X-rays or strong magnetic fields ( 48 );
• General sensitivity to toxins : People with electromagnetic hypersensitivity have more frequent common colds, are more sensitive to chemicals, and are more likely to be affected by environmental factors such as car exhaust and dental amalgam ( 49 );
• Neurological damage: Consistent evidence of physiological damage to nerves associated with using a mobile phone has been found by medical researchers ( 50 , 51 );
• Brain changes: People with electromagnetic hypersensitivity show different fMRI patterns ( 52 );
• Biomarkers: Blood and saliva tests for diagnosing electromagnetic hypersensitivity are used by doctors aware of the condition, e.g., histamine levels are used to indicate inflammation, and serum malondialdehyde level is used to indicate oxidative stress from cell damage ( 53 , 54 );
• Not psychosomatic: A large proportion of people with electromagnetic hypersensitivity are not cognisant of any harm from radiofrequency prior to experiencing symptoms ( 40 , 55 ). Thus, an “expectation of harm” i.e., nocebo effect cannot be used as the explanation for the condition.

Together, the above results provide converging evidence for the existence of human sensitivity to electromagnetic fields. EHS has recently been reframed as existing at the extreme end of a continuum whereby all humans have some level of electro-awareness and sensitivity but where individuals have varying abilities to repair damage from EMFs due to oxidative stress and other mechanisms ( 56 ). A recent review of EHS research based on the underlying biological mechanisms has noted the need for more relevant diagnostic tests for EHS ( 42 ). The lack of health policies for dealing with EHS has been found to be a global issue, prompting calls for the WHO to develop and promote health policy to assist EHS sufferers ( 57 ).

Man-made radiofrequency is being added to dramatically with 5G signals, including thousands of small cell panels in every city, on street poles and apartment buildings in suburban areas, and close to hospitals and schools. The 5G signals differ from existing technologies because focused beams are used, and the new 5G plan is to use millimeter waves. Previously, millimeter waves were limited to police radar, military radar, and non-lethal weapons for crowd dispersal and airport scanners, which are not considered to be dangerous by authorities due to the short exposure times of use. However, current telecommunications systems emit constantly (24/7). The long-term effects on human health from beamed, pulsed millimeter waves have not been sufficiently studied, so that recent reviews have been unable to draw any strong conclusions ( 58 ) or have stated no confirmed evidence [( 59 ), p. 601] and little consistent evidence [( 60 ), p. 613]. Note that these statements do not mean evidence of no harm and must not be misconstrued that way ( 18 ). Furthermore, the review process itself can be biased or incomplete, as noted in ( 61 ).

Without adequate research, it is hard to formulate public policy, yet the 5G rollout is advancing nevertheless. Public regulatory bodies have attempted to reassure medical practitioners and the general public by advising that 5G millimeter waves will “only enter into the outer layers of the skin.” Such statements ignore the skin's critical biological functions, such as its role in the immune system, waste management and its rich innervation. The sweat duct ends within the epidermis have a helical shape, enabling them to act as antennas, drawing radiofrequency signals into the body ( 62 , 63 ). Furthermore, the rapid, pulsed, narrow beams comprising 5G signals may cause intense hot spots, creating permanent skin and tissue damage ( 64 ). A recently declassified Russian study found an unfavorable influence of millimeter radio-waves on the organism [( 65 ), p. 60] such as bunched and damaged nerves in the skin and surface layers, changes to protein and carbohydrate metabolism, and disturbances of the immune and blood systems. Bioactive and possibly dangerous exposures to 5G millimeter waves may create a cascade of biological events with unknown consequences ( 48 ). At the same time, Russian research has also shown that millimeter waves in specific frequency ranges given in very short doses (e.g., 15 min) can have therapeutic effects that act on the body via the skin ( 66 , 67 ). Overall, there is inadequate research on the impact of 5G waves on the skin ( 68 ), and further investigations are paramount given the current rollout of these technologies and the non-consensual nature of most exposures.

One way to put this situation into context for health care professionals is to compare it with the concept of polypharmacy . When certain drugs are combined, sometimes no studies exist to demonstrate safety. In the case of polypharmacy, nurses are aware that there are risks involved in adding even just a few new drugs to a patient's regime, and that close monitoring for effects is crucial in such cases. Similarly, 5G is being added to the current 2G, 3G and 4G mixture of radiofrequencies. However, there has been no biological safety testing and no corresponding public health warnings about the analogous “polyfrequency” effects on biological systems occurring from multiple exposures to different types of radiofrequencies, including millimeter waves. The unknown effects of such layering of radiofrequencies are flagged in the guidelines of the International Commission on Non-Ionizing Radiation Protection ( 69 ). Despite this caution, no tests have been conducted for such potential additive effects, and the 5G rollout is advancing, unhindered by the current lack of research.

Implications for science and medicine

The above findings have far-reaching implications. From a postpositivist perspective ( 70 ) a scientific truth is being established via converging evidence from many sources and the rejection of alternative explanations. The fact being pointed out is that human systems interact with electromagnetic fields even at low power levels, which challenges the current understanding of human perceptual and signaling systems, and warrants further investigation ( 71 ). From a medical perspective, these results may give some clues about the rising levels in technology dominant countries of serious health conditions such as cancer, Alzheimer's disease and other forms of dementia, as well as illnesses in young people that are on the increase, such as depression, hyperactivity, Type II diabetes, hypertension and psychoses.

Medicine and the lens of biophysics

Health education involves the study of human biology, physiology, biochemistry and anatomy. However, understanding how electromagnetic fields can harm human systems requires an understanding of biophysics i.e., how human biology responds to physical forces. Biophysics explains the electrically sensitive nature of the human body both at the basic level i.e., the role of electrical signaling in the heart, the brain, the nervous system, and also at a cellular level, the voltage-gated channels that enable cells to function and respond to the extracellular environment. The sections below briefly introduce the biophysics of electromagnetic radiation, describing some of the suggested mechanisms of action.

Mechanisms of biological interaction

The literature shows that the effects of radiofrequency are dependent on various wave characteristics such as the frequency of the carrier wave, the frequency of the modulating wave (which rides on top of the carrier wave so as to define the information being carried; e.g., the text message being sent from a mobile phone), the intensity of the wave and whether the wave is pulsed or continuous ( 72 ). Therefore, to understand how electromagnetic fields interact with human biology, there is a complex puzzle to be solved with many dimensions to be considered. While the mechanisms are not yet fully understood, several plausible mechanisms have been postulated, as described below.

Many charges vibrating coherently

Making up the biological system of the body are building blocks such as atoms, molecules and crystals. These small components of life all contain many charged components, which vibrate at various frequencies. Synchronized vibrations between large numbers of charged components can create very large electromagnetic forces that cause the molecules and other biological components to resonate with one another at specific frequencies ( 73 , 74 ). This phenomenon, called “coherence,” may be fundamental to determining which interactions occur between biological components (e.g., between molecules) and even the shapes of various tissues. Fröhlich ( 73 ) warned that because the membranes of cells vibrate at millimeter wave frequencies, they would likely be affected by microwaves oscillating at the same frequency. Fröhlich thus predicted that 5G frequencies would disrupt cell membrane functioning.

Inappropriate movement of Calcium ions

An oscillating electric field can cause inappropriate movement of Calcium ions across cell membranes ( 73 , 74 ). One example is the inappropriate opening of the voltage-gated calcium channels in cell membranes. These are protein “gates” which sit on the external plasma membranes of cells, opening and closing when they detect a specific change in voltage in order to allow Ca++ ions to pass across. It has been shown theoretically that the oscillating electric and magnetic fields of a radiofrequency wave can cause the free calcium ions to vibrate with enough energy that they signal a “false” change in voltage to the gate proteins. This results in the inappropriate opening of the gates and an influx of Ca++ ions through the channels and into the cell ( 75 , 76 ). Calcium influx due to the opening of the calcium gated channels can then result in a myriad of adverse intracellular activities, including nitrosative and oxidative stress, leading to downstream health effects ( 77 , 78 ).

Disruptive movement of charges

The disruptive movement of charges created by the vibrational frequency of a radiofrequency wave can move other charged ionic molecules in unexpected ways. One result is the redistribution of charges in protein molecules, leading to changes in protein structure and subsequent pathologies ( 79 ). Other outcomes include damage to cells, mitochondria, cellular stress, damage to proteins and DNA ( 80 ) as well as incorrect signaling between cellular and neural systems. This can further result in oxidative stress and inflammation, resulting from long-term exposures to disruptive radiofrequency forces, cellular repair mechanisms struggle to keep up with the damage from oxidative stress, resulting in DNA mis-repair and cancer ( 81 ) and cardiovascular disease ( 82 ).

Further understanding of possible mechanisms of action between electromagnetic fields and biological systems has been explored in more depth elsewhere ( 83 – 85 ). Main themes and research needs were also presented in 2017 at a European joint biomedical and engineering conference ( 86 ).

Currently, the above mechanisms are not fully understood and unfortunately used by some as a reason to downplay observed changes. In science, as well as in clinical practice, lack of understanding of the mechanisms of action does not detract from the observed data; e.g., aspirin was used as an anti-inflammatory for over 70 years before its mechanism of action was understood, and the inflammatory and immune suppressant effects of cigarette smoking are still being explored.

Public safety issues

The above evidence basis for the biological effects of microwave radiation has far-reaching implications for public health policy. To date, these implications have not been reflected in the guidelines of international regulatory bodies such as the International Commission on Non-Ionizing Radiation Protection (ICNIRP) that governments look to for guidance on these matters.

Official limits focus on thermal mechanisms only

One well-known mechanism by which radiofrequency wavelengths can damage living tissue is heating, a process well-understood by engineers and physicists. Unfortunately, damage from heating as the only mechanism of harm is assumed and used as the basis for the ICNIRP safety guidelines, which specify power density thresholds for radiofrequency exposures beyond which the public must not be exposed. Industry must comply with these limits to prevent short-term heating effects from medical devices, smart devices and wireless technologies. However, the types of biological harm from radiofrequency described in the sections above are not necessarily due to heating yet may lead to short- and long-term harm to the population. The guidelines do not protect against these biological effects because such effects occur at exposures with much lower power densities than ICNIRP guidelines permit, which set the “safety” thresholds at a power density of 10,000 milliwatts/m 2 ( 69 ) and an average whole-body heat absorption (SAR) of 0.08 Watts/kilogram. At much lower power densities, Frey found the human heart is sensitive to pulsed signals (at 3 microwatts/cm 2 ; i.e., 30 milliwatts/m 2 ) ( 87 ), and Salford found dark neurons in the brains of rats (at 240 and 2,400 milliwatts/m 2 ). A recent review of over 100 studies using very low intensity exposures has revealed that the median SAR at which effects occur is 0.0165 W/kg ( 3 ). These works, showing significant effects at very small doses, demonstrate that there is no clear linear dose-response relationship (where greater the RF power absorption, the greater the adverse effect). The invalid assumption of a linear-dose relationship is embodied within the ICNIRP guidelines. What is more true is that exposure dose is a product of both exposure intensity and time of exposure ( 3 ); however, the ICNIRP guidelines do not cater for exposures longer than 30 min. Moreover, the guidelines do not consider modulation and pulsing, which may be the more bioactive components of wireless signals ( 17 ). Altogether, these results position the ICNIRP guidelines as invalid and irrelevant to real-world exposure scenarios.

Lack of protection for vulnerable populations

The most recent ICNIRP guidelines ( 69 ) do not have a stricter category for children, babies, fetuses, sperm or ovaries, thereby treating them all the same as adults; i.e., as “members of the public.” Exposures to members of the public are uncontrolled exposures and should protect against plausible risk, as specified by the International Commission on Radiation Protection (ICRP) ( 88 ). ICNIRP radiation protection philosophy does not align with ICRP best practices and does not provide protection or “opt-out” rights for people who do not want to be exposed, such as those with microwave sickness or electromagnetic hypersensitivity. This situation is also in contrast with the Russian Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing (Rospotrebnadzor) , which has heeded their scientists' warnings that children are in the “at risk” group ( 89 ) and has subsequently issued guidelines for schools and parents on the safe use of mobile phones. In addition, the governments of Cyprus, France and Israel have banned Wi-Fi in nurseries and schools.

Around the world, RF protection is determined at the national level, where exposure guidelines and limits for most countries are based on values derived by ICNIRP. However, there are ongoing debates about the adequacy of these guidelines, raising questions about whether they are sufficiently protective ( 90 ). There are also questions from researchers outside of WHO and ICNIRP, about the independence of ICNIRP from industry, and freedom of independent thought within ICNIRP ( 91 ). A recent review has shown that in the majority, ICNIRP affiliates belong to a small group of 17 self-referencing authors ( 92 ).

In the case of radiofrequency exposures, poor guidance and lack of transparency has meant that neither medical professionals nor the public has been adequately advised about potential harm. Consequently, patients may only realize their brain tumor is linked to their mobile phone usage when it is far too late, as was the case for the late Robert Kane, a previous telecommunications engineer and employee of Motorola ( 93 ). The situation is similar to the levels of medical and public awareness in the middle of the last century regarding the link between smoking and lung cancer.

Invoking a precautionary approach

Globally, government regulators of medical services such as X-ray units take a precautionary approach to managing low-dose ionizing radiation, even though the long-term biological effects of very low doses of X-rays are considered uncertain. Precaution means that action needs to be taken to reduce risks, and the decision making behind these actions needs to be justified, open and transparent ( 94 ). The same philosophy must prevail with non-ionizing radiofrequency radiation in that the Precautionary Principle should be invoked in hospital settings, schools, workplaces, public places and in the home ( 95 – 97 ). Several countries have adopted a precautionary stance, such as China, India, Poland, Russia, Italy and Switzerland, regions of Belgium and cities such as Paris. Unfortunately, in most other countries, the current ICNIRP guidelines have been wholly adopted by government radiation protection agencies as standard without due consideration for risk assessment and protection ( 98 ).

Practical applications for health professionals

The above overview shows how radiofrequency signals comprise an ever-present environmental stressor that may contribute to the significant increases in chronic illnesses and mental health issues observed globally. A list of suggestions surrounding best practices with issues related to radiofrequency exposures are offered below to assist health professionals in making the healthcare environment safer and to equip them to advocate for the health, safety and rights of their patients, e.g., as is articulated in the Code of Ethics for Nurses, Provisions 3, 5, 6–9 ( 99 ). Steps that health professionals can take include:

• Responding appropriately to patients with electromagnetic hypersensitivity : When presenting to hospitals or clinics, EHS patients may ask for tablets and laptops or office Wi-Fi to be disabled (Airplane Mode on, Location Services off). They may also request for distancing from cordless phones, which can affect the heart ( 100 ). The uninformed health care worker may be confused and no know how to respond. To provide guidance, the Austrian Medical Association has written a set of Guidelines ( 6 ), which include recording patient history, examination, measurement, prevention or reduction of exposure, diagnosis and treatment. Prevention includes removing sources of radiofrequency by switching off, unplugging, shielding, distancing, or using wired connections as an alternative.
• Recording cases with links between symptoms and EMR exposures : Peel ( 101 ) has suggested that professionals' experiences can help identify possible sources of uncertainty and evaluate the health risks due to various environments. Therefore, if health care workers record cases where they observe patients who seem to be affected by radiofrequency, this will provide data for positive change in the future.
• Being mindful of radiofrequency as a possible contributor to illnesses when patients present. This includes developing an awareness of the radiofrequency emitting devices in the environment that may be causing distress to some patients ( 6 ).
• Self-education : Healthcare workers typically strive to stay up to date with the current medical evidence base. Accordingly, they can investigate the effects of radiofrequency on the health of their patients and the general public. The references in this report provide a good grounding and helpful sites for medical professionals. For example, the Physicians' Health Initiative for Radiation and Environment in the UK provides practical “how-to”' advice ( 102 ), and has recently issued a consensus statement ( 103 ) regarding the health effects of radiofrequency exposures. The Environmental Health Trust 2 provides short videos and modules explaining the primary research and applications, such as the effects of cell phones on the body ( 104 ).
• Giving guidance to patients: Healthcare workers are in a position to advise on healthy lifestyles, particularly those working in Primary Care. In these settings, they can speak one-on-one with patients about the risks associated with mobile phone use and show them how to use their phones more safely. The existing online resources ( 6 , 102 , 104 ) can be used to devise educational leaflets for placement in clinics and waiting rooms.
• Institutional education : Doctors and other medical professionals, particularly those in psychiatry and psychology, need to understand how biological harm can occur from exposure to physical entities in the built environment and how the downstream effects may contribute to ailments in their patients. At the same time, courses that provide general training on epidemiological and toxicological aspects of environmental health ( 105 ) also need to include the biological and health effects of electromagnetic fields. A 21st-century tertiary curriculum incorporating biophysics needs to be designed for relevant graduate courses and modules for continuing professional development.
• Precaution in health care delivery: Those responsible for the design and delivery of healthcare need to consider electromagnetic fields in the environment. In face-to-face settings, this means precaution in placing electromagnetic equipment and radiofrequency devices in waiting rooms and treatment areas.
• Policy needed for eHealth: Internet-based health services bring many advantages; however, the technology needs to be used wisely. Because the health effects of EMFs are unknown to most practitioners and policy makers, eHealth practices are currently running ahead of the science and potentially causing harm. Patients and health professionals need to be aware of the potential adverse combinative effects that exposure to wireless devices may have on health conditions; e.g., using a wireless modem connection to consult a practitioner, a smartwatch to report a heart rate ( 106 ) or sending heart data wirelessly from inside an ambulance carrying a heart attack patient may all exacerbate heart injury ( 82 ). Wired solutions need to be put in place for all eHealth services where possible, and policy makers need to lobby research institutions to find appropriate eHealth solutions that first do no harm.

Man-made radiofrequency signals from everyday devices and communications technology infrastructure constitute an environmental stressor, well-documented as creating various adverse biological effects. Plausible mechanisms in which harm can occur initially on a cellular level have been proposed, and these mechanisms are known to have subsequent downstream health effects. The application of the ICRP radiation protection philosophy and framework for the protection of members of the public is over 90 years in the making and is absent in setting exposure limits for this form of (wireless) radiation. The extensive evidence base is compelling enough to call for an update in medical education and practice. Out of care for their patients, healthcare workers may develop their understanding using the practical methods introduced in this discussion paper. Furthermore, modern institutional practices need to be reviewed to ensure that any harm from electromagnetic fields is reduced as much as reasonably possible while still providing optimal health care.

Author contributions

All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication.

1 ODEB is a free online research tool ( https://a037613.fmphost.com/fmi/webd/Research_Review_V4 ). To assist users to best use this database, a webinar has been created ( https://www.orsaa.org/orsaa-database-training-webinar.html ).

2 https://ehtrust.org

ORSAA has self-funded this research and wishes to thank Mr. Bruce Rowe (musician) for his generous donation, without which this research would not be possible. The authors declare that this study received funding from the late Bruce Rowe as a bequest from his estate. Neither the funder nor anyone associated with him was involved in the study design, collection, analysis, interpretation of data, the writing of this article, or the decision to submit it for publication.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher's note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Supplementary material

The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fpubh.2022.986315/full#supplementary-material

Innovative PaddleSat Concept for Thin Satellite Construction Honored

Oct 10, 2023 —.

Student researchers Vaibhav Ghosale (middle) and Grishma Kalepu (right) being presented the WiSEE Best Paper Award from Juan Fraire, the conference’s technical program committee chair.

A team of researchers from the Georgia Tech School of Electrical and Computer Engineering (ECE) has won the Best Paper Award at the 2023 IEEE Wireless in Space and Extreme Environments (WiSEE) international conference.

The team is comprised of Professor Greg Durgin and graduate students Vaibhav Bhosale, Jonathan Dolan, Grishma Kalepu, and Deeksha Manjunath. Their award-winning paper, “PaddleSats: Attitude Control and Station-Keeping for Ultra-Low Density SSP Satellites,” was selected from a field of 37 international papers.

The research presents the authors’ new PaddleSat concept in which satellites are constructed from uniformly thin surfaces, using deflections in their solar panels and subsequent changes in solar pressure-induced momentum to perform station-keeping operations. Such satellites have low launch costs and very long lifetimes in space, as there is no longer the need to carry station-keeping fuel.

PaddleSats also mitigate space debris concerns as the uniformly thin satellites will—without intervention from their controller—gradually descend from orbit (either in fragments or as a whole) due to the influence of solar pressure on the spacecraft. The PaddleSat concept is crucial for developing space solar power satellites for green energy or even low-cost communication satellites that do not contribute long-term orbital debris.

The four students who co-authored the paper began investigating the concept in 2022 as an “ECE 6390 Satellite Communications and Navigation Systems” course project. They continued to refine their work after the course, which led to this original, award-winning concept paper.

The IEEE WiSEE international conference series has been a home for the top-tier research in wireless-related systems in space for the last 11 years. The researchers were honored at this year’s conference held in Aveiro, Portugal from September 6-8.

Top photo caption: Student researchers Vaibhav Ghosale (middle) and Grishma Kalepu (right) being presented the WiSEE Best Paper Award from Juan Fraire, the conference’s technical program committee chair.

A Review of LiFi Technology

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