SAR Value & Health

Vertu

2008-09-12T04:30:00.002-07:00

Toshiba

2008-09-12T04:30:00.001-07:00

Sony Ericsson

2008-09-12T04:28:00.002-07:00

Siemens

2008-09-12T04:28:00.001-07:00

Sharp

2008-09-12T04:18:00.000-07:00

Samsung

2008-09-12T04:16:00.001-07:00

Sagem

2008-09-12T04:15:00.000-07:00

Philips

2008-09-12T04:14:00.002-07:00

Pantech

2008-09-12T04:14:00.001-07:00

Panasonic

2008-09-12T04:13:00.003-07:00

Palm

2008-09-12T04:13:00.001-07:00

Nokia

2008-09-12T02:37:00.000-07:00

Motorola

2008-09-12T02:14:00.000-07:00

LG

2008-09-12T01:48:00.002-07:00

Levi's

2008-09-12T01:48:00.001-07:00

HTC

2008-09-12T01:46:00.002-07:00

ETEN

2008-09-12T01:46:00.001-07:00

BlackBerry

2008-09-12T01:45:00.001-07:00

Asus

2008-09-12T01:43:00.001-07:00

Apple

2008-09-12T01:42:00.000-07:00

Alcatel

2008-09-12T00:30:00.000-07:00

Electromagnetic fields and public health: mobile telephones and their base stations

2008-07-09T04:59:00.000-07:00

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).

Use of mobile phones

In many countries, over half the population already use mobile phones and the market is still growing rapidly. The industry predicts that there will be as many as 1.6 billion mobile phone subscribers worldwide in the year 2005. Because of this, increasing numbers of mobile base stations have had to be installed. Base stations are low-powered radio antennae that communicate with users' handsets. In early 2000 there were about 20,000 base stations in operation the United Kingdom and about 82,000 cell sites in the United States, with each cell site holding one or more base stations.

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.

Exposure levels

Mobile phone handsets and base stations present quite different exposure situations. RF exposure to a user of a mobile phone is far higher than to a person living near a cellular base station. However, apart from infrequent signals used to maintain links with nearby base stations, the handset transmits RF energy only while a call is being made, whereas base stations are continuously transmitting signals.

Handsets: Mobile phone handsets are low-powered RF transmitters, emitting maximum powers in the range of 0.2 to 0.6 watts. Other types of hand held transmitter, such as "walkie talkies", may emit 10 watts or more. The RF field strength (and hence RF exposure to a user) falls off rapidly with distance from the handset. Therefore, the RF exposure to a user of a mobile phone located 10s of centimetres from the head (using a "hands free" appliance) is far lower than to a user who places the headset against the head. RF exposures to nearby people are very low.

Base stations: Base stations transmit power levels from a few watts to 100 watts or more, depending on the size of the region or "cell" that they are designed to service. Base station antennae are typically about 20-30 cm in width and a metre in length, mounted on buildings or towers at a height of from 15 to 50 metres above ground. These antennae emit RF beams that are typically very narrow in the vertical direction but quite broad in the horizontal direction. Because of the narrow vertical spread of the beam, the RF field intensity at the ground directly below the antenna is low. The RF field intensity increases slightly as one moves away from the base station and then decreases at greater distances from the antenna.

Typically within 2-5 metres of some antennae mounted on rooftops, fences keep people away from places where the RF fields exceed exposure limits. Since antennae direct their power outward, and do not radiate significant amounts of energy from their back surfaces or towards the top or bottom of the antenna, the levels of RF energy inside or to the sides of the building are normally very low.

Other RF sources in the community: Paging and other communications antennae such as those used by fire, police and emergency services, operate at similar power levels as cellular base stations, and often at a similar frequency. In many urban areas television and radio broadcast antennae commonly transmit higher RF levels than do mobile base stations.

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.

EMF guidelines

International guidelines developed by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) are based on a careful analysis of all scientific literature (both thermal and non-thermal effects) and offer protection against all identified hazards of RF energy with large safety margins. Both measurements and calculations show that RF signal levels in areas of public access from base stations are far below international guidelines, typically by a factor of 100 or more. RF exposure levels to a user from mobile handsets are considerably larger but below international guidelines.

What WHO is doing

In response to public concerns, WHO established the International Electromagnetic Fields (EMF) Project to assess the scientific evidence of possible health effects of EMF. Specific studies have been identified to address the problem of localised exposure. The project has established a formal mechanism for reviewing the research results and conducting risk assessments of RF exposure. It is also developing public information materials, and bringing together standards groups worldwide in an attempt to harmonise international exposure standards.

WHO is also conducting RF research. A large epidemiology study is being co-ordinated in over 10 countries by the International Agency for Research on Cancer (IARC) -- a specialised cancer research agency of WHO -- to identify if there are links between use of mobile phones and head and neck cancers. The study is anticipated to be completed in 2003.

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 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.
Consultations with the community in siting base stations: Base station sites must offer good signal coverage and be accessible for maintenance. While RF field levels around base stations are not considered a health risk, siting decisions should take into account aesthetics and public sensibilities. Siting base stations near kindergartens, schools and playgrounds may need special consideration. Open communication and discussion between the mobile phone operator, local council and the public during the planning stages for a new antenna can help create public understanding and greater acceptance of a new facility.
Providing information: An effective system of health information and communications among scientists, governments, industry and the public is needed to raise the level of general understanding about mobile phone technology and reduce any mistrust and fears, both real and perceived. This information should be accurate, and at the same time be appropriate in its level of discussion and understandable to the intended audience.

Warning: Using a mobile phone while pregnant can seriously damage your baby

2008-07-09T04:53:00.000-07:00

Study of 13,000 children exposes link between use of handsets and later behavioural problems

The Independent / Health News

By Geoffrey Lean, Environment Editor

Sunday, 18 May 2008

Scientists found that mothers who did use the handsets were 54 per cent more likely to have children with behavioural problems and that the likelihood increased with the amount of potential exposure to the radiation

Women who use mobile phones when pregnant are more likely to give birth to children with behavioural problems, according to authoritative research.

A giant study, which surveyed more than 13,000 children, found that using the handsets just two or three times a day was enough to raise the risk of their babies developing hyperactivity and difficulties with conduct, emotions and relationships by the time they reached school age. And it adds that the likelihood is even greater if the children themselves used the phones before the age of seven.

The results of the study, the first of its kind, have taken the top scientists who conducted it by surprise. But they follow warnings against both pregnant women and children using mobiles by the official Russian radiation watchdog body, which believes that the peril they pose “is not much lower than the risk to children’s health from tobacco or alcohol”.

The research – at the universities of California, Los Angeles (UCLA) and Aarhus, Denmark – is to be published in the July issue of the journal Epidemiology and will carry particular weight because one of its authors has been sceptical that mobile phones pose a risk to health.

UCLA’s Professor Leeka Kheifets – who serves on a key committee of the International Commission on Non-Ionizing Radiation Protection, the body that sets the guidelines for exposure to mobile phones – wrote three and a half years ago that the results of studies on people who used them “to date give no consistent evidence of a causal relationship between exposure to radiofrequency fields and any adverse health effect”.

The scientists questioned the mothers of 13,159 children born in Denmark in the late 1990s about their use of the phones in pregnancy, and their children’s use of them and behaviour up to the age of seven. As they gave birth before mobiles became universal, about half of the mothers had used them infrequently or not at all, enabling comparisons to be made.

They found that mothers who did use the handsets were 54 per cent more likely to have children with behavioural problems and that the likelihood increased with the amount of potential exposure to the radiation. And when the children also later used the phones they were, overall, 80 per cent more likely to suffer from difficulties with behaviour. They were 25 per cent more at risk from emotional problems, 34 per cent more likely to suffer from difficulties relating to their peers, 35 per cent more likely to be hyperactive, and 49 per cent more prone to problems with conduct.

The scientists say that the results were “unexpected”, and that they knew of no biological mechanisms that could cause them. But when they tried to explain them by accounting for other possible causes – such as smoking during pregnancy, family psychiatric history or socio-economic status – they found that, far from disappearing, the association with mobile phone use got even stronger.

They add that there might be other possible explanations that they did not examine – such as that mothers who used the phones frequently might pay less attention to their children – and stress that the results “should be interpreted with caution” and checked by further studies. But they conclude that “if they are real they would have major public health implications”.

Professor Sam Milham, of the blue-chip Mount Sinai School of Medicine in New York, and the University of Washington School of Public Health – one of the pioneers of research in the field – said last week that he had no doubt that the results were real. He pointed out that recent Canadian research on pregnant rats exposed to similar radiation had found structural changes in their offspring’s brains.

The Russian National Committee on Non-Ionizing Radiation Protection says that use of the phones by both pregnant women and children should be “limited”. It concludes that children who talk on the handsets are likely to suffer from “disruption of memory, decline of attention, diminishing learning and cognitive abilities, increased irritability” in the short term, and that longer-term hazards include “depressive syndrome” and “degeneration of the nervous structures of the brain”.

What is SAR Value?

2008-07-09T04:41:00.000-07:00

Specific Absorption Rate (SAR) is a measure of the maximum rate at which radio frequency (RF) energy is absorbed by the body when exposed to radio-frequency electromagnetic field. It is used for exposure to fields between 100kHz and 10 GHz.

The SAR value will depend heavily on the geometry of the part of the body that is exposed to the RF energy, and on the exact location and geometry of the source of the RF energy. Thus tests must be made with each specific source, such as a mobile phone model, and at the intended position of use. The value cited for a specific model is then the maximum level measured in the body part studied.

The most common use is in relation to mobile phones, and here the mobile phone is placed at the head in a talk position. The SAR value measured is then value measured in the place that has the highest absorption rate in the entire head, which for a mobile phone often is as close to the phone as possible. Various governments have defined safety limits for exposure to RF energy produced by mobile devices that mainly exposes the head or a limb for the RF energy:

United States: the FCC requires that phones sold have a SAR level at or below 1.6 watts per kilogram (W/kg) taken over a volume of 1 gram of tissue.

European Union: the SAR limit is 2 W/kg, averaged over ten grams of tissue.

For whole body exposure there is a limit of 0,08 Watt/kg averaged over the whole body.

For more informations: http://www.icnirp.org/documents/emfgdl.pdf