How mobiles work
Mobile devices use radio waves, also called radio frequency (RF) fields, to send and receive calls, texts, emails, pictures, web, TV and downloads. The RF field carries a signal to the nearest base station (often called masts or antennas), which sends the signal to a digital telephone exchange and on to the main telephone network. This connects the signal to the receiving mobile, again via a base station (if it is another mobile device). Without base stations mobiles will not work and we cannot connect our customers’ calls.
Mobiles connect to the base station providing the best signal - usually the nearest. The more power a mobile uses, the greater the potential exposure to RF fields, however the mobile automatically adjusts to use the minimum power needed to communicate with the base station. This depends on a range of factors, including:
- The distance between the mobile and the base station
- The landscape and buildings between the mobile and the base station
- The operating frequency band at a given time
- The service the mobile is being used for (e.g. texting, data or voice calls)
If they would like to, people can reduce their RF exposure from using a mobile device, as indicated by the WHO.
Mobiles and health
The vast majority of experts agree that mobile devices do not produce enough RF energy to cause long-term changes in the body.
Based on thousands of scientific studies, the World Health Organization (WHO) concludes in its factsheet, Electromagnetic fields and public health: mobile phones, published in June 2011, that "no adverse health effects have been established as being caused by mobile phone use."
The full findings of the International Agency for Research on Cancer (IARC), a specialist agency within the World Health Organization (WHO), evaluating the carcinogenic hazard to humans of radiofrequency electromagnetic fields (RF-EMF), were published on 19 April 2013 in Monograph 102.
The IARC Working Group met in May 2011 to classify the cancer hazard of RF-EMF, including those from broadcast and mobile communications, microwaves and radar. This process resulted in RF-EMF being classified as "possibly carcinogenic to humans (Group 2B), based on an increased risk for glioma, a malignant type of brain cancer, associated with wireless phone use." A summary of their findings was published in The Lancet Oncology, which concluded that there is "limited evidence in humans" for the carcinogenicity of RF-EMF.
In May 2010, the International Agency for Research on Cancer (IARC) published the first combined findings from all study centres of the Interphone study, a major piece of research into the possible health effects of mobile devices.The study observed no overall increase in the risk of glioma or meningioma (tumours of the head) from the use of mobile devices. This is consistent with expert reviews of the large body of existing research. While Interphone researchers reported that there may be an increased risk of glioma at the highest exposure levels, they discussed limitations in the study which prevent them from stating a causal link. IARC recommends further investigation into long-term heavy use of mobile devices.
The UK National Health Service reports that Interphone does not provide evidence that mobile phones cause cancer: "While there is a need for further research into longer-term mobile phone use, this study certainly does not support the clear-cut claims of some newspapers that "talking for 30 minutes a day" increases the risk of brain tumours."
Exposure from mobiles
Exposure to radio frequency (RF) fields from mobile devices is measured using the specific absorption rate (SAR) - the amount of energy from an RF field absorbed by the human body, expressed as watts per kilogram (W/kg).
SAR is the accepted international measure of exposure to electromagnetic fields, and the SAR value determined under standardised test conditions for a particular mobile is provided in the product safety information when it is bought.
The International Commission for Non-Ionizing Radiation Protection (ICNIRP) guidelinesrecommend a maximum SAR value of 2W/kg for a mobile, and which, in August 2009, ICNIRP confirmed were still valid. All mobiles operating below this level are considered safe to use. Some countries such as Canada, South Korea and the United States have adopted slightly lower SAR limits of 1.6W/kg for the head and the trunk. Mobiles are tested to ensure compliance with the SAR limit for the countries where they are sold.
The United States' Federal Communications Commission (FCC) explains what SAR values mean in its consumer fact sheet. This fact sheet states that:
“While SAR values are an important tool in judging the maximum possible exposure to RF energy from a particular model of cell phone, a single SAR value does not provide sufficient information about the amount of RF exposure under typical usage conditions to reliably compare individual cell phone models.”
The level of exposure depends on the distance between the person and the mobile and the amount of RF power the mobile transmits. Mobiles always use the minimum amount of energy to provide a service, so actual exposure varies continually depending on a range of factors:
- The distance between the person and the mobile device. RF fields are much weaker even a short distance from a mobile. Keeping the mobile away from the body by using an earpiece or loudspeaker function will significantly reduce exposure.
- The distance from the base station. The signal from a base station becomes weaker the further away the mobile is, meaning the RF field strength from the mobile must increase so it can still communicate with the base station.
- The landscape between the user and the base station. If there is a building, hill or other obstruction between the mobile and the base station, the signal from the base station may also be weaker.
- The service being used. Making a voice call from a mobile leads to greater exposure to RF fields than texts, emails, pictures, web, TV and downloads. This is because voice calls are generally made with the mobile next to the head, while it is held away from the body when sending texts and emails and watching TV. Calls also take longer than sending texts and emails, again increasing exposure.
Vodafone continues to require manufacturers to test the amount of energy from a radio frequency (RF) field absorbed by the human body – the specific absorption rate (SAR) of mobile devices – when used against the ear or near the body.
The International Electrotechnical Commission (IEC) standard for testing mobile device use close to the body was published in April 2010, but has not yet been incorporated into EU Regulations. We have been actively advocating its adoption at a European level. Until this happens, we will continue to require testing using the FCC methodology.
International guidelines ensure that all mobile devices and their base stations operate within strict radio frequency (RF) exposure limits set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). These guidelines have a substantial safety margin built into them and are the basis for ensuring our technology is safe.
We also take advice from health experts such as the World Health Organization (WHO). The WHO states that: “To date, no adverse health effects have been established as being caused by mobile phone use”.
In its fact sheet Electromagnetic fields and public health: mobile phones, the WHO states that: "While an increased risk of brain tumors is not established, the increasing use of mobile phones and the lack of data for mobile phone use over time periods longer than 15 years warrant further research of mobile phone use and brain cancer risk".
People can reduce their RF exposure from using a mobile device in the following ways, as indicated by the WHO: "In addition to using "hands-free" devices, which keep mobile phones away from the head and body during phone calls, exposure is also reduced by limiting the number and length of calls. Using the phone in areas of good reception also decreases exposure as it allows the phone to transmit at reduced power".
There have been attempts to design mobile covers that absorb RF fields, to reduce a person's exposure. The WHO advises that the effectiveness of the covers is unproven. They are also likely to affect the quality of service, and may in fact increase the mobile's operating power.
Children and mobiles
A mobile device can improve children's personal security, as they can maintain contact with their parents and get help in emergencies.
Some parents are concerned their children's health may be affected by using mobiles. They may choose to consider what experts say about children's use of mobiles, as well as the security benefits.
The majority of scientific opinion, supported by the World Health Organization (WHO), is that from the research undertaken to-date there is no clear evidence that mobile phones or base stations present adverse risks to human health - and that there is no evidence that children are at special risk. However, with the likelihood of today’s younger population using mobile phones over a longer period, the WHO has identified further research into the use of mobiles by children of different ages as a priority and further research into use by children and long-term use is underway. Vodafone closely monitors the results of such research and the views of organisations such as the WHO.
To help parents make an informed decision about their children’s mobile use, we provide information and advice from the WHO and its linked organisations.
In its factsheet, Electromagnetic fields and public health: mobile phones, published in June 2011, the WHO states that “no adverse health effects have been established as being caused by mobile phone use”. It provided the following information on how to reduce RF exposure from using a mobile phone: “In addition to using "hands-free" devices, which keep mobile phones away from the head and body during phone calls, exposure is also reduced by limiting the number and length of calls. Using the phone in areas of good reception also decreases exposure as it allows the phone to transmit at reduced power".
We also provide information from the International Agency for Research on Cancer (IARC) and the International Commission on Non-Ionizing Radiation Protection (ICNIRP), both of which are part of the WHO. See the boxes below for more details.
Information from the International Agency for Research on Cancer (IARC)
The full findings of the International Agency for Research on Cancer (IARC), a specialist agency within the World Health Organization (WHO), evaluating the carcinogenic hazard of radiofrequency electromagnetic fields (RF EMF) to humans, were published on 19 April 2013.
The IARC Working Group originally met in May 2011 to classify the cancer hazard of RF-EMF, including those from broadcast and mobile communications, microwaves and radar. This process resulted in RF-EMF being classified as "possibly carcinogenic to humans (Group 2B), based on an increased risk for glioma, a malignant type of brain cancer, associated with wireless phone use." A summary of their findings was published in The Lancet Oncology, which concluded that there is "limited evidence in humans" for the carcinogenicity of RF-EMF.
The IARC classification only considers whether there is a possible link between long-term heavy mobile device use and cancer, it does not assess the likelihood of this link arising. To understand the likelihood and therefore the potential risk posed, the WHO will carry out a wider health risk assessment, which will take into account all the available science relating to RF and health, including the IARC classification and work done by ICNIRP.
Other studies are also underway under the WHO's research agenda priorities. The results of one such study, the CEFALO study into mobile use in children, were published in July 2011. The study involved nearly 1,000 children in Denmark, Sweden, Norway and Switzerland. The study compared mobile use by children and adolescents aged 7-19 years, who were diagnosed with a brain tumour between 2004 and 2008, with that of a randomly selected group of the same age range.
The study found no overall evidence of increased risk of brain cancer, concluding that: "The absence of an exposure - response relationship either in terms of the amount of mobile phone use or by localization of the brain tumour argues against a causal association".
Information from the International Commission on Non-Ionizing Radiation Protection (ICNIRP)
ICNIRP produces guidelines governing radio frequency (RF) exposure from mobile devices and base stations, and these are designed to protect the whole population, including children. All phones and devices sold by Vodafone and all base stations operated by Vodafone, are designed to comply fully with the ICNIRP guidelines.
In August 2009, ICNIRP released a statement confirming there is no scientific evidence to suggest that using a mobile device poses adverse health risks for adults or children.
ICNIRP also published a review of the scientific evidence concerning RF exposure in 2009. This states that: "The experimental data do not suggest so far that children are more susceptible than adults to RF radiation, but few relevant studies have been conducted" and that "Overall, there is no robust evidence of any effect of mobile phone type RF on children or adolescents".
In May 2011, the WHO and ICNIRP held an international health expert meeting on children and non-ionizing radiation. The meeting aimed: "to determine if the ICNIRP guidelines are adequate to protect children - who are different in terms of physiology, anatomy and lifestyle".
Following the meeting, the Chairman of ICNIRP concluded: "From the scientific results of the workshop, we can conclude that our guidance is adequate. For UV radiation, we do know that people are at risk and now we have even more evidence for this position. In contrast, for EMF, and mobiles in particular, there is no evidence that children are at special risk. This means that there is no reason to change current guidelines. Nevertheless we will continue to review the science, and the outcome of this workshop has contributed to that".
Mobile technology is advancing all the time to provide new services, better coverage and higher speeds. Current technologies available to our customers include GSM, 3G, 4G, Wi-Fi and femtocells.
Introducing new services means we have to expand our network to handle the increased traffic. This may involve installing new base stations, where possible on existing structures, such as buildings and towers, to minimise visual impact.
All new mobile devices and base stations comply with the international safety guidelines for public exposure to radiofrequency (RF) fields set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP), which, in August 2009, ICNIRP confirmed were still valid.
4G is the latest generation of mobile device network, which provides faster broadband internet access to devices such as smartphones, tablets and laptops. 4G technology manages mobile internet data more efficiently, making surfing the web using a mobile device more reliable and at speeds closer to those of fixed-line broadband.
2G technology enabled mobile phones to make calls and send text messages, and 3G technology added fast access to the internet and a range of other data services from mobile devices.
With more people wanting to watch TV, make video calls and play online games on the go, faster data transfer speeds are needed to support these more advanced services. The introduction of 4G is making this possible.
4G provides up to 100 megabits per second (Mbps) download speed and up to 50 Mbps upload speeds. Typical downloads can be five to seven times faster than those for existing 3G networks - so instead of taking 20 minutes to download a music album, it could take just over 3 minutes*.
Higher data transfer speeds using 4G will mean people can access more content on their mobile devices than they could using 3G, including high-definition mobile TV, video conferencing and cloud computing.
4G is subject to existing international safety guidelines for public exposure to RF fields, which, in August 2009, ICNIRP confirmed were still valid. The guideline levels include substantial safety margins and the World Health Organization (WHO) states that exposure below these levels does "not appear to have any known consequence on health".
Wireless networks are commonly used to create cable-free computer networks, to connect to the internet and to connect electronic items from mobile devices and games consoles to TVs and DVD players. This is clearly much more convenient than using a cable, because people are much freer to use their equipment in different places. Wi-Fi and wireless devices use similar RF signals to mobiles and base stations, and similar concerns over health and well-being have been raised.
The World Health Organization factsheet on base stations and wireless technologies states that:
"Considering the very low exposure levels and research results collected to date, there is no convincing scientific evidence that the weak RF signals from base stations and wireless networks cause adverse health effects."
If you would like to reduce exposure when using a wireless device, as when using a mobile device, the WHO fact sheet suggests steps that can be taken. These include, keeping wireless devices away from your head and body.
A femtocell is a low-power wireless access point that provides improved localised wireless coverage as a support for the mobile network. 'Femto' means one quadrillionth in the metric measurement system, in the same way that 'deci' means a tenth and 'centi' means one hundredth. Femtocells do not literally cover an area a quadrillionth of the size of a regular base station, but are essentially very small versions of the same thing. They look similar to a wireless internet router and are straightforward to install at home or in the office.
Radio signals inside buildings are sometimes weaker than outside because buildings and walls hinder the radio waves being transmitted to and from the base station. This can sometimes reduce the signal quality, and mobiles have to use more power to connect to the base station.
Femtocells can improve coverage by connecting to the Vodafone network using an existing broadband connection. They then create a local mobile device signal that allows connection with mobile devices close to it. Typically, several mobiles will be able to transmit data and make calls through one femtocell at the same time.
For Vodafone, femtocells are a great way to increase our network coverage and capacity without necessarily installing more base stations. They provide a high-quality, high-speed signal, giving improved voice calls and faster data downloads when using a mobile device inside, enabling people to access the latest services when at home or at the office. What's more, thanks to the improved connection to the Vodafone network, the mobile will use less power, so the battery may last longer and RF exposure may be reduced.
Like mobiles, base stations and Wi-Fi, femtocells use very low level radiofrequency (RF) fields to receive and transmit data. They comply with the same public limits for exposure to RF fields that apply to other wireless devices, which are set by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). As with mobiles, there is no scientific evidence that the very low levels of RF exposure from femtocells can be harmful to health.
The RF power output that femtocells use is less than 0.1 watt, similar to other wireless home network equipment, such as a Wi-Fi router. Mobiles connected to a femtocell typically operate at a similar power level to other wireless phones used in the home.
For more information visit EMF Explained Series - Femtocells and Health.
* Download speeds based on existing average of 1 Mbps for 3G and 6 Mbps for 4G services.
Base stations and health
Mobile devices cannot work without base stations. Our comprehensive network of base stations allows us to keep improving our coverage and to introduce new services such as video calling, internet and mobile TV. Most people welcome improved coverage and services, but we recognise that expanding our network can sometimes cause concern, usually about the visual impact of base stations or health issues concerning radio frequency (RF) fields.
The International Commission for Non-Ionizing Radiation Protection (ICNIRP) has issued guidelines for limiting exposure to RF fields, including from base stations. These guidelines have a safety margin built into them, and all our base stations comply. In fact, public exposure to RF fields from our base stations is typically many times below the guideline limit.
The majority of experts and national advisory boards say there is no scientific reason to distance base stations from places where people live and work, as long as the ICNIRP guidelines are adhered to. The World Health Organization’s (WHO) factsheet on base stations and wireless technologies concludes that "there is no convincing scientific evidence that the weak RF (radio frequency) signals from base stations and wireless networks cause adverse health effects". The WHO has no plans to conduct further research into the effects of RF exposure from base stations, as it is not considered necessary.
Our operating companies gather and communicate information about RF exposure from our base stations. For example in Greece, we work with two local universities through the HERMES Program to monitor electromagnetic radiation emitted by various radio frequency sources in the environment. In the UK, government regulator Ofcom publishes a directory of mobile phone base stations.
Exposure from base stations
Base stations use radio signals to connect mobile devices to the network, enabling people to send and receive calls, texts, emails, pictures, web, TV and downloads.
Radio frequency (RF) fields spread out from an antenna high on the supporting structure, like a beam of light from a lighthouse. The RF field strength is greatest close to the antenna at the height level with the antenna. Where necessary, our base stations have signs, barriers and other controls in place to restrict access to this area. There is a ‘blind spot’ between the beam and the mast where exposure is very low. At ground level, the RF field strength initially increases as the distance from the base station grows. After it peaks, it reduces rapidly as the distance increases.
This means that, when an antenna is placed on a rooftop, be it on a house, school or office, the people in the building directly below receive very low exposure. The area where people receive the greatest exposure is typically between 50 and 200 metres away, depending on the height and angle of the antenna. However, this is still a fraction of the recommended limit for public exposure to RF from base stations set by the International Commission for Non-Ionizing Radiation Protection (ICNIRP) guidelines, which, in August 2009, ICNIRP confirmed were still valid.
All our base stations comply with the ICNIRP guidelines. The power of an individual base station varies depending on the area covered, but is typically between 2 and 150 watts. Micro-cell base stations that give extra coverage and capacity in busy areas, and in and around buildings, usually have a power of between 1 and 2 watts. This means people’s maximum exposure is usually between 0.01% and 2% of the ICNIRP guideline limits for public exposure. Even people who live or work near a base station are not exposed to more than this amount.
The World Health Organization (WHO) factsheet on base stations and wireless technologies concludes that "there is no convincing scientific evidence that the weak RF (radio frequency) signals from base stations and wireless networks cause adverse health effects". The WHO has no plans to conduct further research into the effects of RF exposure from base stations, as it is not considered necessary.
4G: providing faster internet access
4G provides faster broadband internet access to devices such as smartphones, tablets and laptops. 4G technology manages mobile internet data more efficiently, making surfing the web using a mobile device more reliable and at speeds closer to those of fixed-line broadband.
Vodafone offers 72% 4G population coverage, increased from 32% in September 2013 and increasing to over 90% by March 2016.
There have been thousands of scientific studies into the effects of radio frequency (RF) fields on health. Scientists know more about this than they do about most chemicals. Find out more about the scientific process.
Authorities including the World Health Organization (WHO) agree there is no evidence that convinces experts that exposure to RF fields from mobile devices and base stations operated within guideline limits has any adverse health effects.
However, there are still some gaps in scientific knowledge. We look to the WHO to identify and prioritise research needs and are dedicated to supporting independent scientific research into these areas.
Scientists and public health officials assess risks to human health based on the entire body of evidence, rather than individual scientific studies. The evidence is considered by panels of experts in this field. We look to such expert reviews for advice on mobile devices, masts and health.
The World Health Organization's International EMF Project records global research into mobile devices, masts and health and prioritises research needs. We look to the WHO to review, identify and define health research needs, for example in their RF research agenda.
- Population-based studies
- Effects on the brain
- Early life and children
- Ageing and degenerative disease
- RF exposure levels from new technologies.
Vodafone acknowledges this uncertainty and is dedicated to developing scientific understanding of the effects of mobiles on health. We fund our share of the cost of independent national, regional and international scientific research in these priority areas. We do this through national research programmes and funding organisations to ensure the research is independent of industry influence. Since 1999, we have spent over £9 million on research.
We believe research is best conducted under frameworks requiring that:
- Researchers design and report their studies independently of third parties
- Research is of the highest standard
- Research is published in peer-reviewed literature.
We will consider providing information to enable the best quality research upon request.
We review all major research into mobiles and health and will update our policies and practices if one of the following bodies advises that the findings change the overall weight of scientific evidence:
- The WHO (including the International Agency for Research on Cancer)
- A reference review
- A body which has previously prepared a reference review
- An external expert review commissioned by Vodafone
Current research programmes
We are dedicated to developing scientific understanding of the effects of mobile devices and base stations on health by funding independent scientific research into the priority areas identified by the World Health Organization (WHO). We do this through national research programmes and funding organisations such as the second phase of the Mobile Telecommunications and Health Research Programme (MTHR 2) in the UK (now transferred to the Department of Health, Research Initiative on Health and Mobile Telecommunications (RIHMT)), and the GSM Association, to ensure the research is independent of industry influence. We also respond to requests for technical advice from researchers.
We all sometimes disagree with others about the things we see in the world around us, and experience things at odds with our present understanding. Science aims to explain the things we experience and improve our understanding.
The scientific method is the series of steps that all scientists should follow. By following these steps correctly, scientists ensure their results are not affected by external influences such as their own or others’ prior beliefs.
The steps in the scientific method are:
- Observation or idea
- Experiments to test hypothesis
- Peer review
- Replication (typically by other scientists)
It is important to question whether the scientific method has been followed when news stories draw attention to the latest miracle cure or health scare. For example, if a scientist publicises their work directly to the media rather than through a peer-reviewed journal, their results should be treated with caution. Even if a study has been published in a peer-reviewed journal, it is only one step towards reaching a considered opinion on any health consequences.
At Vodafone, we only consider the opinion of panels commissioned by recognised national or international health agencies such as the World Health Organization. Their opinions are based on the entire body of evidence, rather than on the basis of single scientific studies.
Advice from the WHO
The World Health Organization (WHO) has published a number of fact sheets providing information and guidance on electromagnetic fields (EMF) and public health.
Considering short and long-term effects
The June 2011 fact sheet considers both the short-term and long-term effects of using mobile devices, and concludes that:
"To date, no adverse health effects have been established as being caused by mobile phone use."
In the short term, the WHO states that:
"At the frequencies used by mobile phones, most of the energy is absorbed by the skin and other superficial tissues, resulting in negligible temperature rise in the brain or any other organs of the body".
"To date, research does not suggest any consistent evidence of adverse health effects from exposure to radiofrequency fields at levels below those that cause tissue heating. Further, research has not been able to provide support for a causal relationship between exposure to electromagnetic fields and self-reported symptoms, or "electromagnetic hypersensitivity."
In the long term, the WHO states that:
"Epidemiological research examining potential long-term risks from radiofrequency exposure has mostly looked for an association between brain tumours and mobile phone use. However, because many cancers are not detectable until many years after the interactions that led to the tumour, and since mobile phones were not widely used until the early 1990s, epidemiological studies at present can only assess those cancers that become evident within shorter time periods. However, results of animal studies consistently show no increased cancer risk for long-term exposure to radiofrequency fields."
The fact sheet also references the first combined findings of the Interphone study, a major piece of research into the possible health effects of mobiles phones. The study, published in May 2010, concludes:
"The international pooled analysis of data gathered from 13 participating countries found no increased risk of glioma or meningioma with mobile phone use of more than 10 years."
In response to this study, the WHO concludes:
"While an increased risk of brain tumors is not established, the increasing use of mobile phones and the lack of data for mobile phone use over time periods longer than 15 years warrant further research of mobile phone use and brain cancer risk. In particular, with the recent popularity of mobile phone use among younger people, and therefore a potentially longer lifetime of exposure, WHO has promoted further research on this group. Several studies investigating potential health effects in children and adolescents are underway."
Understanding base station and wireless technologies' impacts
The conclusion of the WHO fact sheet on Base stations and wireless technologies, published in May 2006, is that:
"Considering the very low exposure levels and research results collected to date, there is no convincing scientific evidence that the weak RF signals from base stations and wireless networks cause adverse health effects."
Conclusions from the WHO:
"In the area of biological effects and medical applications of non-ionizing radiation approximately 25,000 articles have been published over the past 30 years. Despite the feeling of some people that more research needs to be done, scientific knowledge in this area is now more extensive than for most chemicals. Based on a recent in-depth review of the scientific literature, the WHO concluded that current evidence does not confirm the existence of any health consequences from exposure to low level electromagnetic fields. However, some gaps in knowledge about biological effects exist and need further research."
Since 2001, there have been a significant number of expert reviews of scientific research studies into mobiles, masts and health published by expert panels around the world. Here, find a summary of reviews published from 2006 to date and see the table of expert reviews for a complete list of reviews meeting our standards of scientific rigour.