Base stations and health

Base stations are designed to send and receive electrical signals from mobile devices and relay them to a core switching centre. Each base station consists of antennas and a cabinet with equipment to power it. The antennas are usually fixed to a support structure, which is known as a mast.

Your mobile phone only works if it can connect to a base station. 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 International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines are adhered to. These guidelines include a substantial safety margin.

The World Health Organization (WHO) fact sheet on base stations and wireless technologies states that:

“…There is no convincing scientific evidence that the weak RF (radio frequency) signals from base stations and wireless networks cause adverse health effects.”

Surveys have shown that the RF exposures from base stations range from 0.002% to 2% of the levels of international exposure guidelines, depending on a variety of factors such as the proximity to the antenna and the surrounding environment.

Mobile devices and health

Your mobile device converts radio waves into electrical signals in order to send and receive your communications. At its peak (when the phone is turned on), power use ranges between 0.1 and 2 watts. The radio waves that mobile devices rely on are at the non-ionising end of the electromagnetic spectrum. While a mobile device is used close to the human body, a small amount of energy from the radio waves is absorbed and this is converted into heat.

Scientific research has concluded that a temperature rise of no more than one degree Celsius is a safe level for the body. Our normal biological processes cool us down and prevent any significant temperature rise in our bodies.

The vast majority of experts, including the WHO, agree that mobiles, operated in line with international guidelines, do not produce enough energy – and therefore heat – to cause long-term changes in the body.

WHO periodically reviews the science and is currently conducting another risk assessment of radio frequency electromagnetic fields. This is based on an extensive review of scientific studies published since their first review in 1993 and is due to be published inbetween 2017 and 2018.

Mobile devices:

• Need base stations to work and connect customers' calls
• Use radio frequency (RF) fields to send and receive calls, texts, emails, pictures, web, TV and downloads
• An RF signal is sent 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 device, again via a base station (if it is another mobile device)
• Use the minimum transmit power needed to communicate with the base station
• This automatically adjusts according to the signal at the base station. The better the signal – the lower the transmitted power needed from the mobile device. The power needed depends on a range of factors, including:
  1. Distance between the mobile device and the base station;
  2. Landscape and buildings between the mobile device and the base station;
  3. Operating frequency band at a given time; and
  4. The service the mobile device is being used for (eg texting, data or voice calls);
• Connect to the base station providing the best signal – usually the nearest.

As a person moves away from the base station the signal becomes weaker, so the mobile device automatically adjusts its own transmit power to maintain the minimum needed to communicate with the base station.

The area covered by a base station is known as a cell. Each cell is usually split into three sectors, which overlap with the sectors of neighbouring cells to create an uninterrupted network. When people travel, the signal is passed from one base station to the next, and typically never has to travel further than the nearest base station.

The size and shape of each cell is determined by the features of the surrounding area, such as buildings, trees and hills, which can block signals.

• Cells are largest in flat open landscapes, where they can cover a radius of several kilometres.
• Cells in urban areas typically cover up to a two kilometre radius.
• The smallest cells, covering a few tens or hundreds of metres, are in built up areas, where micro-cell base stations are used to provide extra coverage and capacity.

Each base station can only handle a limited number of connections at a time.

• In areas of high demand, additional antennas are sometimes added to a base station to send and receive more calls and other mobile services, or an extra base station is installed.
• A large number of base stations are needed to allow more people to use mobile devices, from more locations, and for coverage to be continuous when moving around.

Children and mobile devices

All our phones and devices conform to international guidelines, which ensure protection for everyone.

The International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines are designed to protect the entire population, irrespective of a person’s age, and include a substantial safety margin.

Children use mobiles to study, stay in touch, for gaming and to go online. Some parents are concerned that their children’s health may be affected by their regular use. To help parents make an informed decision about their children’s mobile use, we provide information and advice from the World Health Organization (WHO) and its linked organisations.

The majority of national and international scientific opinion, including from WHO, has concluded that the research undertaken to date shows no evidence of risks to human health.

“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 as being caused by mobile phone use.” WHO, October 2014

As young people today are likely to use mobile phones over a much longer period in their lifetime, WHO has made it a priority to carry out further research into this area. Studies into the use of mobiles by children and usage of more than 10 years are currently under way. Vodafone closely monitors the results of such research and the views of international bodies such as WHO.

Information from International Agency for Research on Cancer (IARC)

In May 2011, IARC classified radio frequency (RF) fields as possibly carcinogenic to humans, and stated that more research is needed in this area. A number of studies are already 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 to 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 localisation of the brain tumor argues against a causal association”.

Information from International Commission on Non-Ionizing Radiation Protection (ICNIRP)

ICNIRP produces guidelines governing 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 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.”

Wave spectrum

Electromagnetic fileds

Further reading