Eight questions on exposure to electromagnetic waves
We are exposed to electromagnetic fields and waves on a daily basis: from sunlight, during X-ray examinations, when standing near electrical cables or while using our mobile phones. What exactly are they? What are their potential health effects? Can they also have consequences on animal health? Can we limit our exposure and if so, how? This article provides some answers.
1. What waves are we exposed to?
A radio or television antenna or a mobile phone in use generates electromagnetic fields that propagate through the environment in the form of waves. There are also electromagnetic fields of natural origin such as the Earth's magnetic field or fields generated by lightning. Other naturally occurring electromagnetic waves include ultraviolet radiation and visible light from the Sun.
Waves carry energy and can be used to transmit data, which is why they are used in radio communications.
Electromagnetic waves or fields are characterised by their frequency, i.e. the number of oscillations of the electromagnetic field in one second. This frequency is expressed in Hertz.
The main electromagnetic fields created by human activities are:
- static and low-frequency electromagnetic fields (from 0 to about 10 kHz) generated by:
- high-voltage power lines, and power cables for electrical distribution, including in the home;
- all household appliances: any appliance that runs on electricity emits an electric field when it is plugged in and a magnetic field when it is in use.
- radiofrequency electromagnetic fields (from about 10 kHz to 300 GHz) are used, for example, in information transmission:
- TV, radio and mobile phone transmitters;
- Wi-Fi transmitters;
- contactless communication devices (RFID).
Lastly, electromagnetic fields are also widely used in industry and the medical sector:
- Radar in the aviation, maritime and automotive fields, for example.
- Magnetic resonance imaging (MRI), therapeutic applications, etc.
- Resistance welding, induction furnaces, etc.
2. What are the effects of electromagnetic waves on the human body?
Exposure to high-intensity low-frequency electromagnetic fields, such as those emitted by certain industrial machines, for example, can stimulate the nervous tissue of the human body, as well as the retina.
In the area of radiofrequencies, exposure to high levels of electromagnetic waves can cause heating of biological tissues (the skin, but also the body's internal tissues); this is known as the thermal effect. However, the exposure limits currently in force in France ensure that such levels of radio waves are never reached in public places or under the normal conditions of use of emitting devices.
Some experimental studies have shown that biological effects can also occur from exposure to lower levels of electromagnetic fields than those causing nerve stimulation (low frequency) or a significant increase in tissue temperature (radiofrequency). These effects include temporary changes in the functioning of certain cells or organs. However, such biological changes are regularly observed as part of the body's normal functioning. In addition, exposure to the waves emitted by a mobile phone has been associated with a change in the electrical activity of the brain. However, these effects have not been shown to have any impact on health.
Lastly, the simultaneous exposure of populations to numerous sources of electromagnetic fields has raised the question of the possible effects that could be associated with this multiple exposure.
Given this complexity, only a multidisciplinary approach can meet the challenges to health risk assessment posed by technological innovations. The working groups set up by ANSES to assess these risks bring together biologists, epidemiologists, physicists, risk assessors and researchers specialising in the area of interactions between electromagnetic fields and the human body, who together contribute to meeting these challenges.
What is ANSES's role?
ANSES assesses the possible health effects of electromagnetic fields in order to inform public decision-making. In particular, the Agency has issued opinions on the health effects of 5G deployment, high-voltage lines, body scanners and light-emitting diodes.
3. Are mobile phone waves dangerous to health?
Based on current knowledge, the Agency's work does not show any causal link between exposure to the waves emitted by mobile communication technologies and health effects.
However, some publications have suggested a possible long-term increased risk of brain tumours for heavy mobile phone users, which is why the IARC (International Agency for Research on Cancer) has classified radiofrequency electromagnetic fields as "possibly carcinogenic".
ANSES's most recent expert appraisals had also highlighted, with limited levels of proof, various biological effects in humans and in animals, some of which had already been reported in a previous expert appraisal published in 2009, concerning sleep, male animal fertility and cognitive performance. Indeed, biological effects corresponding to generally reversible alterations in internal bodily function were observed, as in the case of exposure to various everyday stimuli . However, to date, no link between the biological effects described in cell, animal or human models and any resulting health effects has been demonstrated.
SAR, a key index for limiting exposure
Some of the energy carried by electromagnetic waves that interact with the human body is reflected back outwards, while the rest is absorbed. To quantify this effect, the reference measurement is the specific absorption rate (SAR), for all waves between 100 kHz and 6 GHz. The SAR is expressed in Watts per kilogram (W/kg).
To limit exposure to these waves, users are advised to buy mobile phones with the lowest SAR values.
4. High-voltage power lines: what are the health risks?
Populations are exposed to many sources of low-frequency electromagnetic fields, including power lines, transformers and modes of transport outdoors, or electrical appliances inside the home.
The home is the source of the highest levels of magnetic fields, produced by domestic appliances, but the associated exposure is usually very brief and localised. Outside the home, the highest electromagnetic field values are measured primarily under very-high-voltage power lines or next to transformers and electricity substations. Some industrial activities may also generate much higher exposure to low-frequency magnetic fields.
ANSES has not found any causal link between exposure to low-frequency electromagnetic fields in the everyday environment and health effects. However, there are still questions about the possible long-term effect of exposure to sources of these fields – such as very high-voltage power lines – on the occurrence of childhood leukaemia or the onset of neurodegenerative diseases. Nevertheless, no biological mechanism to explain the epidemiological observations has yet been identified.
5. What is electromagnetic hypersensitivity?
For several decades, the scientific literature has been reporting cases of people claiming to suffer from various symptoms that they attribute to their exposure to electromagnetic fields emitted by household appliances, electrical installations or mobile technologies. This is what is known as electromagnetic hypersensitivity.
Current scientific knowledge shows no cause-and-effect relationship between the symptoms of people declaring themselves as electrohypersensitive (EHS) and their exposure to electromagnetic waves. However, in an expert appraisal on this specific topic, the Agency stressed that the pain and suffering (headaches, sleep, attention and memory disorders, social isolation, etc.) expressed by the people declaring themselves as EHS is a reality, requiring them to adapt their daily lives to cope with it. The Agency recommended pursuing research work, in particular by setting up studies whose experimental conditions take into account the circumstances of people declaring themselves as EHS.
6. Are there any risks to livestock animals?
The Agency's expert appraisal published in 2015 on the consequences of exposure to extremely low-frequency electromagnetic fields on farm animal health stressed that it is still difficult to give an opinion on this subject.
In 2021, the Agency also issued an opinion on disorders on two cattle farms located near a wind farm, a facility connected to the electricity grid and a source of electromagnetic fields. It concluded that the problems encountered – reduced milk yield and quality, behavioural problems, increased mortality – were most likely unrelated to the presence of the wind turbines.
7. How are electromagnetic waves regulated?
In France, as in most European countries, regulatory limit values for exposure of the general population to electromagnetic fields have been set in accordance with the European Union's 1999 recommendations (Recommendation 1999/519/EC). These limit values are intended to protect people and the environment from the harmful effects of electromagnetic fields.
Exposure of the public to radiofrequencies emitted by equipment used in telecommunications networks or by radio installations is thus specifically regulated (Decree No. 2002-775 of 3 May 2002). It is monitored by the French Frequency Agency (ANFR). The checks carried out each year show that environmental exposure to radio waves is well below the regulatory limits. Of the 4700 measurements carried out in 2020, almost 80% showed exposure of less than 1 volt per metre (V/m), whereas the regulatory limit values are between 28 and 87 V/m depending on the frequency. All these measures are made public.
The ANFR also carries out numerous checks on the SAR of mobile phones and, if the limit values are exceeded, it proposes that the terminals in question be updated or even withdrawn from the market.
How do I know if I am exposed to waves?
Under the national programme for the surveillance and measurement of public exposure to electromagnetic waves, managed by the ANFR, any individual, along with the State, local authorities and approved associations, can request that exposure be measured free of charge to waves generated by a relay antenna or communicating object such as the Linky smart electricity meter. Measurements can be carried out both in residential premises and in places accessible to the public (parks, shops, stations, etc.).
To enable the health risks of waves to be assessed, the results of these measurements are transmitted to ANSES under Article 42 of the Grenelle I Act of 3 August 20091.
Regarding exposure to low frequencies, following the Grenelle 1 and 2 Acts, a system for monitoring and verifying electromagnetic fields emitted by public electricity transmission networks was set up. The data collected in this context are published on this site.
8. How can you limit your exposure to waves?
Limit exposure to waves emitted by mobile telephones (radiofrequencies):
- in "talk" mode, intensive adult users of mobile telephones should use hands-free accessories more systematically and, more generally, all users should make phone calls when they have a good signal, and choose telephones with the lowest specific absorption rate (SAR) values;
- children should use mobile phones in moderation and, in particular, should use hands-free kits. This is because children can be more exposed than adults because of their morphological and anatomical features, in particular their small size, as well as the characteristics of some of their biological tissues.
Limit exposure to low-frequency magnetic fields (electric currents):
In the workplace, some jobs, particularly in connection with the use of certain industrial machines, may involve greater exposure to low-frequency magnetic fields. The Agency therefore stresses the need for better control of exposure in the workplace for certain professionals, particularly pregnant women.
Stakeholders responsible for land use planning should stop any further increase in the number of vulnerable people exposed around high-voltage lines by avoiding:
- the establishment or development of new facilities accommodating vulnerable people (hospitals, schools, etc.) immediately next to very-high-voltage power lines;
- the installation of new power lines over these facilities.
1 ANSES, represented by its Director General, is responsible for the processing of personal data intended for characterising population exposure to radiofrequency electromagnetic fields. The Data Protection Officer at ANSES is the Director of Legal Affairs (email@example.com). This processing is based on ANSES's public interest mission. Data are kept for a period of 5 years. In accordance with the provisions of Regulation (EU) 2016/679 on the protection of natural persons with regard to the processing of personal data and on the free movement of such data (GDPR) and the French Data Protection Act of 6 January 1978, as amended, you have the right to access, rectify, limit and in certain cases delete any information concerning you. You can also, for any legitimate reason, object to the processing of any data concerning you. Your information is passed on to the team responsible for processing the measurement data on exposure to electromagnetic fields. You can access information about yourself by contacting: firstname.lastname@example.org. If, after contacting us, you feel that your rights with regard to data protection have been infringed, you can submit a complaint to the French Data Protection Authority (CNIL).