Frequently asked questions
Mobile handsets and devices work by sending and receiving low-power radio signals. These signals are exchanged with antennae which are connected to radio equipment, commonly known as base stations. In turn, the base stations are connected to the rest of the communications networks (landline and mobile) and they transmit the signal from or to those networks.
To provide a good-quality mobile communications service, the base stations must be located near to where mobile devices are used.Generally, the design of a mobile network is based on a “cellular grid” which covers a geographical area. The number of base stations required for an area will depend on the type of terrain and the number of people using mobile telephones. The more people that are using mobile telephones at the same time, the more capacity is needed, so it is necessary to install more base stations and these have to be closer to each other.
Mobile handsets and devices and base stations are perfectly designed to meet the strict national and international security standards and, of course, all the recommendations of the World Health Organisation.What are 2G, 3G and 4G networks?
3G or third generation networks are an evolution of 2G or second generation networks. 2G technologies include GSM (voice calls) and GPRS, which facilitates data communications. 3G technologies such as UMTS and HSPA permit mobile broadband, as well as voice calls, as they are technologies orientated towards high-speed data transmission. The evolution of 3G takes us to technologies of the fourth generation, 4G, such as LTE, which will permit super-fast data communications.Other wireless technologies
Other technologies that make use of radio waves in order to function are Bluetooth, Wi-Fi and NFC.
Bluetooth can be used to permit communication between devices which are very close to each other, such as headphones and hands-free equipment. Wi-Fi makes it possible to connect to the Internet from our Smartphone, Tablet or PC without the need for cables. And with NFC we will be able to carry out certain operations such a payments using mobile phones.LTE promises faster data rates than current mobile technologies, does that mean higher exposures from the antenna sites and will this grow with more data traffic?
LTE will improve data speeds and network capacity by carrying data more efficiently. This is needed to meet the high expectations and demands customers place on mobile communication applications and services both in their professional and private life. The power from an LTE base station will vary in response to the amount of data traffic. The maximum exposure levels will be similar to other mobile services using similar transmitter powersAre there safety standards for LTE devices?
Yes, LTE devices have to comply with the same type of safety limits as mobile phones. LTE devices LTE devices include data modems (such as USB ‘dongles’, smartphones and tablets. Exposure guidelines for mobile phones and devices used close to the head or body specify the maximum level of RF energy that can be absorbed with a large safety margin. The term for the amount of RF energy absorbed by the body or the head during a phone call or use of a mobile device is the Specific Absorption Rate or SAR. SAR is expressed in units of watts per kilogram (W/kg).
The maximum SAR level for a mobile phone used against the head or body in accordance with the international guidelines is 2 W/kg measured over a 10 gram averaging mass. Smartphones (including LTE devices) are tested for SAR compliance at the highest certified power level in laboratory conditions.
www.sartick.comDo I need to take any precautions when I use my LTE device?
All equipment transmitting radio signals must comply with national or international safety requirements, which also applies to LTE devices. Some devices are designed to have a small minimum separation from the body when in use, typically 15–25 mm depending on the device. This is to ensure that the device operates more efficiently and also meets the SAR requirements. If a separation is required this will be described in the documentation accompanying the device and is normally produced by the manufacturer. No other precautions are required.
In June 2011, the WHO stated: “A large number of studies have been performed over the last two decades to assess whether mobile phones pose a potential health risk. To date, no adverse health effects have been established for mobile phone use”.
Smart metersAre emissions from smart meters are harmful?
We should refer what Scientifics says: The Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) has published a technical report on RF EMF measurements taken from a mesh radio smart meter. It concludes: “The RF electromagnetic energy transmitted in a single pulse from the smart meter is similar to that from a car remote unlocking fob and much less than a single GSM SMS transmission. The measurements do not provide any indication of why smart meter transmissions would provoke symptoms in people otherwise unaffected by other wireless technologies such as mobile phone handsets. Indeed the low levels and short transmission times make any effects highly unlikely.”
“The measured and calculated exposures are all well below the public exposure limits. The radiofrequency used is similar to the frequency used by GSM mobile phones and the peak transmission power is somewhat less. Many other wireless technologies have pulsed structure to their transmissions and many transmit throughout the whole day….The measurements do not provide any indication of why smart meter transmissions would provoke symptoms in people otherwise unaffected by other wireless technologies such as GSM mobile phone handsets.”
BIBLIOGRAPHIC INFORMATION: Wijayasinghe D, Karipidis K. ARPANSA Preliminary Measurements of Radiofrequency Transmissions from a Mesh Radio Smart Meter. Technical Report Series No. 163. 2013 Dec 9.
Electromagnetic fields are natural phenomena that have always been present in our surroundings and which birds and fish use, for example, to orient themselves. Even though some are visible, such as rainbows, most are invisible to the human eye, such as the Earth’s magnetic field that causes compasses to point north or the Sun’s light.
The electromagnetic waves that make up these fields are those used in mobile telephony.What types of waves are there?
When you listen to the radio or watch TV, your receiver is receiving waves. If you have ever thrown a rock into a pool, you will have noticed that its impact on the water generates a wave.All these types of waves, apparently so very different from each other, can be classed into:
What types of electromagnetic waves are there?
- Mechanical waves: waves that need a physical medium to propagate (such as water or air).
- Electromagnetic waves: they do not need a medium to propagate. On the contrary, electromagnetic waves travel very fast through the air. Furthermore, their energy decreases as they move away from the emission source according to a ratio at least inversely proportional to the square of distance, such that at twice the distance the energy is four times lower.
The main feature of electromagnetic waves is frequency, which denotes the number of times the wave cycles in one second, setting apart some waves from others. Frequency is measured in hertzs (Hz).According to their frequency, electromagnetic emissions fall into two kinds:
Is radioactivity the same as radiation (or emission)?
- Ionising: electromagnetic waves of a extremely high frequency (X-rays and gamma rays) that contain enough photon energy to cause ionisation (the conversion of atoms or parts of molecules into ions with a positive or negative electric charge) by breaking the atomic bonds that keep molecules joined inside cells.
- Non-ionising: those generated by mobile telephony. They have so little energy that they cannot cause ionization in biological systems.
No, radioactivity refers to very high-energy emissions that can be of a purely electromagnetic nature, such as gamma rays, or be associated with the emission of subatomic particles, such as alpha and beta particles, produced by radioactive materials. The very high-energy emissions can break molecular bonds, thereby damaging living cells.
The term radiation, however, refers to the property of the electromagnetic energy that powers an antenna to radiate into free space, that is, to propagate and reach another place, where a receiving antenna can recover the enclosed message and decode. The electromagnetic waves used for telecommunications are not ionising e.g. they cannot modify the structure of matter since their energy is very low.How are electromagnetic fields (EMFs) measured?
The energy transmitted by high-frequency electromagnetic waves is usually also expressed as power density, measured in W/m2 (watts per square metre) or other similar parameters.
The biological effects of emissions depend on the time of exposure and the rate of absorption of radio frequency power, which is quantified as the so-called Specific Absorption Rate (SAR) and is expressed in W/Kg (watts per kilogram).
Specific Absorption Rate (SAR)
Radio waves are electromagnetic energy. It is established that such energy can lead to the heating of the body, but radio waves do not have enough energy to damage cell structures and are therefore known as ‘non-ionizing’ radiation. Scientific research has led to the conclusion that a temperature rise of no more than 1 degree Celsius is a safe level for the body to cope with.International health and safety guidelines are in place to limit public exposure to radio waves from base stations and mobile phones, and are set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP).
The unit of measurement for the amount of radio wave energy absorbed by the body when using a mobile phone is SAR, the Specific Absorption Rate. SAR is expressed in units of watts per kilogram (W/kg).
To find SAR information, follow the links to the manufacturer of your handset or visit the Mobile Manufacturers Forum for a summary of mobile phone models tested with their SAR values.
Information on SAR from the US FCC website:
http://www.fcc.gov/cgb/consumerfacts/sar.htmlHow is the SAR value measured?
The SAR for mobile phones is determined at the highest certified power level in laboratory conditions. However, the actual SAR level of the phone while operating can be well below this value. This is because the phone is designed to use the minimum power required to reach the network. Watch video:
Base stationsBase stations comprise several constituent elements:
How do they work?
- Antennas: they allow establishing communication with those users who are inside the coverage area of the base station. They are in charge of emitting or receiving the radio waves that are exchanged with mobile phones. The closer the mobile phones are to the antennas, the better the coverage will be and the lower the powers that must be emitted by both the mobiles and the base.
- Mast: the structure where the antennas are installed. They have different heights, shapes and sizes depending on their location. Usually, antennas must be raised so that the emission and reception of waves is appropriate.
- Equipment shed: in order for antennas to be able to exchange radio waves with mobile phones they need a range of equipment that is installed in a purposely designed shed.
The mobile telephony network consists of a network of base stations that allows the location of the terminal that makes a call and covey its transmission. The coverage area is divided into small cells – which is why it is also known as a cellular network – that can span an area with an approximately radius of 100-200 m in urban areas and of 5 to 8 km in rural or open areas.
The powers emitted by the mobile phone and the station are automatically set to minimum to ensure a good connection quality. When the signal is not sufficiently strong, the transmission is transferred to a neighbouring cell, something which is known as handover.What is the maximum power emitted by the antenna of a base station?
Mobile telephony antennas usually emit at maximum radiated powers of some hundreds of watts (W) and in most cases with maximum absolute levels below the 1,500-2,000 W of the Effective Isotropic Radiated Power (PIRE). Moreover, the actual radiated power is typically a lot smaller than those maximum values, which would be theoretically attainable only in extreme operating conditions since the actual emission power level is automatically set to the minimum necessary to maintain communications. Only the channels occupied and active at any time are emitted such that the aforementioned theoretical values cannot be reached in practice. This characteristic, which is essential in the operation of systems such as those involved in mobile telephony, does not arise in radio and TV broadcastings.
Thus, the power levels that are emitted by mobile telephony base stations are a lot lower than those used by radio and TV broadcasters, which can broadcast with several tens of kilowatts (thousands of watts; 1 kW = 1,000 W) and even megawatts (millions of watts; 1MW = 1,000,000 W).Is the maximum emission level always used?
No. In fact, it is rarely used. The power used depends on the number of simultaneous connections and the distance between the different mobile phones and the base stations that are communicating, or the obstacles present between them.
In order to reduce the emission levels and prevent interferences, the levels are automatically set to the minimum possible values.What is the safety distance from a base station antenna?
Base station antennas are directive, which means that they orient the power in certain directions. The antennas used for mobile telephony emit in the direction perpendicular to the antenna, mainly forward, in the shape of a fan, and practically do not emit backwards or towards the ground.
The safety distance varies according to the power emitted in each direction, which in turn is determined by means of the radiation diagram. The figure shows the typical emission characteristics of mobile telephony antennas.
Therefore, a standard distance cannot be ascertained; it must be calculated for each specific case. On the other hand, any obstacle in the wave’s path (such as walls or ceilings) greatly attenuates the electromagnetic field level, so the distance decreases proportionally. It is worth remembering that the power density declines with the square of the distance.
The calculation of the safety volume is defined by a parallelepiped as that depicted in the figure and whose dimensions are defined from the data corresponding to that antenna.Where are base stations installed?
From a technical standpoint, base stations must be distributed in a regular pattern so that they can provide the appropriate coverage. Thus, in cities it is necessary to arrange them in an orderly fashion; it makes no sense to locate them far away from users.
The greater the number of stations installed in cities, the better the coverage and the quality of service will be. The reason behind this is that the number of users who can communicate at the same time per base station is restricted, at best, to a few dozen. Therefore, in areas where there is a high density of users, cells must be small and abundant so that the number of users in their coverage areas is not too high. This is what is known as the capacity of the base, which, together with the coverage, determines whether the quality of service provided is good or not.Why do they have to be located right in the middle of population centres?
For both service reasons (if no base stations were to be built in populated areas, these areas would not have coverage) and capacity reasons (without enough base stations, not all the demand for communication from all users could be met).
In addition, in order to minimise the emitted power levels and thus the exposure to electromagnetic fields, it is necessary for antennas to be as close as possible to the phones.
The best arrangement is for antennas not to be moved away from urban areas since that way operators can emit with less power and radiation levels can remain sufficiently below safety limits; taking antennas away from urban centres would oblige both the base stations and mobiles to emit with greater power, thereby substantially increasing radio frequency levels and affecting the quality of service.Why has it been necessary to increase the number of base stations in cities?
To be able to provide a service of the best possible quality to mobile telephony users, which are ever growing, use more mobile telephony services (Internet access, e-mail, high-speed, mobile TV, MMS, etc.), for greater lengths of time and from more locations (inside buildings, vehicles, tunnels, trains, underground, and so on). All of this makes it necessary to gradually increase the number of base stations.Let’s go into more detailed about why this increase is necessary:
- To give coverage to a growing number of locations. Expanding the initial number of stations for the basic coverage needed outdoors makes it possible to gradually extend the coverage to the interior of a greater number of buildings, vehicles, car parks, tunnels, railway lines and so on.
- Even though there might be coverage, to have enough capacity to meet all users’ requests. Given that a base station can only deal with a limited number of simultaneous connections, as the number of users and the number of minutes during which they use the services increase, it becomes necessary to install more base stations so that the services do not become saturated.
- In order to use increasingly greater frequencies. Mobile telephony systems have progressively had to use higher frequencies (from the 900 MHz of the starting GSM system to the 2,000 MHz of the current UMTS, by way of the 1,800 MHz band of DCS), something which calls for a greater density of antennas to reduce the attenuations suffered by the waves as they travel through the air and interact with the obstacles they encounter in their path.
- In order to have new applications and services. In the particular case of UMTS – a 3rd generation technology that enables mobile broadband services, the basic voice, SMS and data services must migrate towards new high-speed data transmission services. In order for this to be possible, it is necessary to have a denser network of base stations.
These new data services require antennas and phones to be closer to each other than was the case in basic voice communications. In other words, in order to achieve the appropriate coverage, the distance between adjacent antennas must decrease. In some cases, it could be necessary to even double the number of existing GMS or 2nd generation base stations in order to be able to have a UMTS network that gives service in satisfactory conditions.
On the other hand, it is worth keeping in mind that the denser the network of antennas, the smaller the power levels that must be used by both bases and mobiles to communicate between each other; thus, a lower level of exposure to electromagnetic fields is achieved.Does the size of the mast that supports the antennas have a bearing on their emissions?
No. An antenna and a tower (or mast) are two entirely different things. The tower or mast is a necessary structure for supporting the antennas of a base station; these structures do not emit any type of radiation. Antennas are the elements that emit and receive mobile telephony signals.What kind of electromagnetic fields are we exposed to inside our home?
The fact that it is possible to talk over a mobile, listen to the radio and watch TV inside a house is indicative of the presence of electromagnetic waves. On the other hand, electricity and home appliances generate electromagnetic fields at a frequency of 50 Hz. TV screens and computer monitors and cordless and mobile phones also generate additional fields.
In addition, all radio, TV and mobile telephony emissions that arrive from the outside. On top of that, we receive the emissions from medical emergency, fire brigade, police and civil protection antennas; radar systems; and satellite communications systems.What do the emissions from mobile telephony infrastructures amount to with regard to the total level of exposure to electromagnetic emissions?
According to a study from the UK Radiocommunications Agency and the Institute of Applied Magnetism of the Complutense University of Madrid, only 2-5% of the total amount of electromagnetic emissions received by human beings comes from mobile phone antennas.Are the differences between mobile telephony base station antennas and other types of radio and TV broadcast antennas significant when it comes to evaluating their possible impacts on human health?
Yes. The radio frequency radiation generated by some antennas (particularly, radio, TV and radar antennas) is more powerful than that emitted by mobile telephony antennas.
Mobile phones communicate with the base stations of a mobile telephony system by means of electromagnetic waves. A mobile phone has coverage when it receives the electromagnetic waves from, at least, one base station with a sufficiently strong signal.Why do we lose coverage?
Mobile phones only work properly when they have coverage, that is, when they receive the electromagnetic waves emitted by the antennas of base stations, as with the reception of radio or TV signals. As we move away from an antenna, the power of the waves exchanged between our mobile phone and the base station antenna rises up to a maximum safety level set by Spanish legislation and guaranteed by the manufacturer of the terminal. Once that limit is reached, coverage is lost as a precautionary measure: this is why it is important for mobile phones to be close to antennas as that way they will operate at minimum power and will have the greatest coverage.What are the emission frequencies of base stations and mobile phones?
Current mobile telephony systems use the 900 MHz, 1,800 MHz and 2,000 MHz bands. The 900-MHz frequency band is very close to the one used by TV broadcasters (TV uses the frequencies up to 850 MHz). The frequencies around 1,800 MHz are used by domestic cordless phones.What is the maximum power emitted by a mobile phone?
Mobile phones must meet diverse technical standards in order for them to work properly in mobile telephony networks and with the appropriate guarantees for users as regards the exposure to electromagnetic fields. From among all the parameters that must be satisfied, phones have a maximum power value for which they have been designed and checked.
For terminals that are commonly found in the market, the typical maximum average power values range from 125 mW to 250 mW according to the type of terminal and the frequency band used.
However, in normal conditions, mobile phones emit at levels noticeably lower than their maximum power, given that the value of the power emitted at any time is controlled from the base station by means of a feature called power control, such that only the minimum power necessary to maintain the link is used. This allows to minimise exposure levels and to prevent interferences in the system.
Said power value depends to a large extent on the distance to the base station, the former being, as a general rule, lower the closer the latter is to the mobile phone. Should a power value greater than the maximum possible value be necessary to maintain the link, the communication would be interrupted since the phone cannot emit more power in any case.What is SAR?
When determining what is actually emitted by an antenna, what is measured is the power flux density, that is, the value of the wave’s power per surface area unit (W/m2). However, to express the energy that can be absorbed by a tissue we use the radio frequency power absorption rate, known as the specific absorption rate (SAR).
The biological effects of emissions depend on the exposure time and the quantified SAR. Therefore, SAR is used by the International Commission of Non-Ionizing Radiation Protection (ICNIRP) as a dosimetry unit for setting exposure limits and issuing recommendations (límites de exposición).
The European Standard (Norma Europea EN 50360) issued by the ICNIRP sets a maximum SAR level of 2 W/kg, which must be tested by means of international measurement protocols which are binding on all mobile phone manufacturers.
If you want you know your mobile phone’s SAR, please go to: www.mmfai.orgDo anti-radiation accessories for mobile phones actually reduce emissions?
No. The studies that have been carried out on the anti-radiation devices currently on the market have concluded that, in general, their use does not reduce exposure and, in some cases, it can even increase it because when they attenuate the signal from mobile phones they cause them to emit at greater power to maintain the quality of the transmission; thus, the exposure levels of users go up.
Biomedical aspectsDo health authorities have evidence on the health risks purportedly associated with living or working near mobile telephony base station antennas?
No. According to the World Health Organisation (WHO) and the health authorities, it cannot be concluded from the different studies that have been conducted in this respect that base stations cause adverse health effects.
All scientific committees of reference on this subject agree that there are no health risks involved at such a low emission power. In residential areas near base stations, field levels are greatly below the limit values set by the law (more than 1,000 times lower).
According to current scientific research, the limits in place guarantee the protection of people against electromagnetic fields.What are thermal effects?
The electromagnetic fields generated by base stations and mobile phones cause a transfer of energy that, when it comes into contact with the human body, dissipates as heat through the biological tissues. In the presence of a source of heat of any nature (natural or artificial), the body reacts by removing the heat passively through the blood and actively by sweating. These effects are known as thermal effects.What are non-thermal effects?
Scientists differentiate between thermal effects (increase of temperature) and non-thermal effects, that is, effects that are not related to heat. The criticism levied against mobile phones focuses on the possibility that they may cause non-thermal effects such as sleep disorders, sensory alterations, etc. The exhaustive research programmes that have been set in motion to investigate these claims have not been able to ascertain any of these effects.If there are no health issues related to antenna emissions, how do you explain the public alarm caused and the setting up of Committees of People Affected by antenna radiations?
We must not confuse public alarm with medical alarm. In this case, since there is no health alarm, experts talk of a distorted perception of risk, that is, believing that there is real danger when objectively there is none. The spreading of reliable information will undoubtedly dispel these fears.Do children need more protection against electromagnetic emissions?
The radio frequency exposure limits set in Spanish regulations (RD 1066/2001) assume the criteria of health protection against electromagnetic fields established in the EU Health Ministers’ Council Recommendation, dated 12th July 1999. These limits are those set by the International Commission of Non-Ionizing Radiation Protection (ICNIRP). Said values provide the public at large, including children, with a sufficient margin of safety.
In the opinion of the ICNIRP “there is no need or justification for a specific proposal for the protection of children or other special groups from the general population.”
This Commission is made up of the most distinguished experts on the matter at the international level. Together with the World Health Organisation they protect the safety of the general public.What is hypersensitivity?
The WHO, in its Note no. 206 on sensitivity to electromagnetic fields, published in December 2005, says:
The same scientific studies that endorse the existence of the Electromagnetic Hypersensitivity Syndrome (EHS) state that its symptoms:
- Are NOT correlated to the exposure to electromagnetic fields
- CAN be caused by environmental factors
“The Electromagnetic Hypersensitivity Syndrome is characterised by a variety of non-specific symptoms, which affected people ascribe to an exposure to electromagnetic fields (EMFs). The most commonly experienced symptoms include dermatological symptoms (skin redness, tingling and burning sensations) and neurasthenic and vegetative symptoms (fatigue, tiredness, concentration problems, vertigo, nausea, heart palpitations and digestive disorders). This set of symptoms is not part of any recognised syndrome.”
There is some evidence suggesting that these symptoms could be due more to pre-existing psychiatric conditions and to stress reactions as a result of the worries about the health effects of electromagnetic fields than to the exposure to electromagnetic fields itself.Is there any proof of any long-term effect caused by electromagnetic fields?
No. All the research that has been carried out up to date has not found any evidence of long-term exposure to electromagnetic fields being detrimental to human health. Nevertheless, continuing with this line of research is recommended.Are there any radio frequency experts who are concerned about possible health risks derived from mobile telephony base station antennas?
The mission of a scientist is to consider problems and give answers to them. Therefore, there is an interest in finding out more about the effects and applications of radio frequencies and knowing them better, which is why research goes on as in other scientific fields.
For a more detailed analysis of the health issues associated with mobile phones, we suggest you look up the exhaustive information available at the WHO’s website on electromagnetic fields.What is the IARC?
The International Agency for Research on Cancer (IARC) is part of the World Health Organization (WHO). The main objective of the IARC is to promote international collaboration in cancer research. Its mission is to coordinate and conduct research on the causes of human cancer, the mechanisms of carcinogenesis, and to develop scientific strategies for cancer prevention and control. In short, the IARC is one of the WHO’s advisory agencies, which is committed to establishing the carcinogenic potential of certain substances, processes and practices.
The IARC Monographs Programme identify environmental factors that can cause cancer in humans. The IARC can identify carcinogens even when the risk of suffering cancer is very low. It is not the IARC, but the WHO and health agencies who, after the publication of the IARC classification, determine any measures and policies to be adopted.What is the IARC classification and what does it mean?
IARC classifies carcinogens in five categories, based on the existing scientific evidence for carcinogenicity to humans.
Group 1: Carcinogenic to humans. There is enough evidence to conclude that it can cause cancer in humans. For example, alcoholic drinks, asbestos, tobacco, etc.
Group 2A: “Probably carcinogenic” to humans. This category is used when there is limited evidence of carcinogenicity in humans but sufficient evidence of carcinogenicity in experimental animals. For example, car exhaust fumes, sun lamps, PCBs, etc.
Group 2B: “Possibly carcinogenic” to humans. This category is used when there is limited evidence of carcinogenicity in humans and less than sufficient evidence of carcinogenicity in experimental animals. For example, coffee, petrol fumes, chloroform, ELF, sedatives (Oxazepam), pickled gherkins, barbiturates (Phenobarbital), progesterone-based contraceptives, talcum powder, etc.
Group 3: “Unclassifiable” agents. This category is used when the evidence
of carcinogenicity is inadequate in humans and in experimental animals. For example, caffeine, mercury, saccharine, maté, tea, fluorescent lighting, Kojic acid (used in cosmetics to lighten skin), silicone breast implants, hair dyes, ceramic dental implants, etc.
Group 4: Probably not carcinogenic to humans. There is strong evidence that it does not cause cancer in humans. For example, Caprolactam (the precursor to Nylon).What is the IARC classification and what does it mean?
The World Health Organization (WHO) maintains an extensive database of scientific research into the effects of electromagnetic energy (EME), including studies on the effects of radiofrequencies on public health.
As reviewed by the WHO in 1981 and 1992, research on biological effects and possible health hazards of exposures to radiofrequency fields has been underway for more than 50 years
The WHO database, which is available on their website, shows that there are more than 1900 published scientific articles on the biological and health effects of radiofrequency electromagnetic fields, and more than 630 studies on radiofrequencies specifically used by mobile phone networks.
WHO EMF Research Database http://www.who.int/peh-emf/research/database/en/
Exposure limits are the electromagnetic field limits that must not exceeded in populated areas. These limits are different from the limits at which base stations emit.
Exposure limits are specified as electric field levels (V/m) or power density levels (W/m2). These levels can be calculated and measured through objective methods.How are they determined?
With a method identical to that used to protect people from the effects of any physical or chemical emission: after reviewing all published scientific work, research institutes, scientists and international health protection committees assess the existing risk and recommend the levels that ensure that no adverse health effects take place. These values are totally safe but, just in case, health authorities study them and decide whether they should apply additional safety factors.
In the case of mobile telephony, the reduction factor is 50, a margin deemed by the WHO to ensure the protection of the nearest populations.Which public bodies establish regulations on exposure limits?
There are many bodies throughout the world working on coming up with regulations on the limits of exposure to electromagnetic fields and different methods to measure and evaluate them.
Many of the studies that have been conducted do not result in regulations but only in recommendations because the bodies that have carried them out do not have the authority to demand compliance with them. However, entities such as CENELEC at the European level and the FCC in the United States develop binding regulations.
The following table includes the different values of the reference levels – in terms of power density – for mobile telephony and wireless access frequencies as regards general public exposure.
TABLE 1: Comparison for several frequency bands. General public exposure.What limits does Telefónica meet?
At Telefónica we comply with ICNIRP regulations in all facilities in all countries where we operate.
Talking on a mobile phone, listen to radio and watch TV in a house indicates the presence of electromagnetic waves.
The power levels of mobile phone base stations are much smaller than those of radio or TV transmitters.
The radio frequency electromagnetic energy of a smart meter is similar to the remote control car.