Electromagnetic Fields And Public Health
Mobile Telephones and Their Base Stations:
Mobile telephones, sometimes called cellular phones or handies, are now an integral part of modern telecommunications. In some parts of the world, they are the most reliable or only phones available. In others, mobile phones are very popular because they allow people to maintain continuous communication without hampering freedom of movement.
This fact sheet has been updated in the light of recent reviews of the effects on human beings of exposure to radiofrequency (RF) fields conducted by the World Health Organization (WHO) in November 1999, the Royal Society of Canada (1999), and a review on mobile phones and health by an expert committee in the United Kingdom (IEGMP 2000).
Concerns for health:
Given the immense numbers of users of mobile phones, even small adverse effects on health
could have major public health implications. This fact sheet addresses these concerns.
Several important considerations must be kept in mind when evaluating possible health effects of RF fields. One is the frequency of operation. Current mobile phone systems operate at frequencies between 800 and 1800 MHz. It is important not to confuse such RF fields with ionizing radiation, such as X-rays or gamma rays. Unlike ionizing radiation, RF fields cannot cause ionization or radioactivity in the body. Because of this, RF fields are called non-ionizing.
Health effects:
RF fields penetrate exposed tissues to depths that depend on the frequency - up to a centimetre at the frequencies used by mobile phones. RF energy is absorbed in the body and produces heat, but the body's normal thermoregulatory processes carry this heat away. All established health effects of RF exposure are clearly related to heating. While RF energy can interact with body tissues at levels too low to cause any significant heating, no study has shown adverse health effects at exposure levels below international guideline limits.
Most studies have examined the results of short-term, whole body exposure to RF fields at levels far higher than those normally associated with wireless communications. With the advent of such devices as walkie-talkies and mobile phones, it has become apparent that few studies address the consequences of localised exposures to RF fields to the head.
WHO has identified research needs to make better health risk assessment and promoted the research to funding agencies. Briefly, at present time this research indicates:
Cancer:
Current scientific evidence indicates that exposure to RF fields, such as those emitted by mobile phones and their base stations, is unlikely to induce or promote cancers. Several studies of animals exposed to RF fields similar to those emitted by mobile phones found no evidence that RF causes or promotes brain cancer. While one 1997 study found that RF fields increased the rate at which genetically engineered mice developed lymphoma, the health implications of this result is unclear. Several studies are underway to confirm this finding and determine any relevance of these results to cancer in human beings. Three recent epidemiological studies found no convincing evidence of increase in risk of cancer or any other disease with use of mobile phones.
Other health risks:
Scientists have reported other effects of using mobile phones including changes in brain activity, reaction times, and sleep patterns. These effects are small and have no apparent health significance. More studies are in progress to try to confirm these findings.
Driving:
Research has clearly shown an increased risk of traffic accidents when mobile phones (either handheld or with a "hands-free" kit) are used while driving.
Electromagnetic Interference:
When mobile phones are used close to some medical devices (including pacemakers, implantable defibrillators, and certain hearing aids) there is the possibility of causing interference. There is also the potential of interference between mobile phones and aircraft electronics.
Conclusions and recommendations:
None of the recent reviews have concluded that exposure to the RF fields from mobile phones or their base stations causes any adverse health consequence. However, there are gaps in knowledge that have been identified for further research to better assess health risks. It will take about 3-4 years for the required RF research to be completed, evaluated and to publish the final results of any health risks. In the meantime, WHO recommends:
Strict adherence to health-based guidelines:
International guidelines have been developed to protect everyone in the population: mobile phone users, those who work near or live around base stations, as well as people who do not use mobile phones.
Precautionary measures:
Government: If regulatory authorities have adopted health-based guidelines but, because of public concerns, would like to introduce additional precautionary measures to reduce exposure to RF fields, they should not undermine the science base of the guidelines by incorporating arbitrary additional safety factors into the exposure limits. Precautionary measures should be introduced as a separate policy that encourages, through voluntary means, the reduction of RF fields by equipment manufacturers and the public. Details of such measures are given in a separate WHO Background document.
Individuals: Present scientific information does not indicate the need for any special precautions for use of mobile phones. If individuals are concerned, they might choose to limit their own or their children’s’ RF exposure by limiting the length of calls, or using "hands-free" devices to keep mobile phones away from the head and body.
Obey local restrictions on mobile phone use to avoid EMF (Electromagnetic Fields) interference: Mobile phones may interfere with certain electromedical devices, such as cardiac pacemakers and hearing aids. In hospital intensive care departments mobile phone use can be a danger to patients and should not be used in these areas. Similarly mobile phones should not be used in aircraft as they may interfere with its navigation systems.
Driving safety:
In moving vehicles there is a well established increase in the risk of traffic accidents while the driver is using a mobile phone, either a conventional handset or one fitted with a "hands free" device. Motorists should be strongly discouraged from using mobile phones while driving.
Simple protective measures:
Fences or barriers or other protective measures are needed for some base stations (principally, those located on building rooftops) to preclude unauthorised access to areas where exposure limits may be exceeded.
RF absorbing devices: Scientific evidence does not indicate any need for RF-absorbing covers or other "absorbing devices" on mobile phones. They cannot be justified on health grounds and the effectiveness of many such devices in reducing RF exposure is unproven.