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What does SAR stand for and what does it relate to in association with mobile phones
01:00 Mon 11th Feb 2002 | Technology
A. SAR stands for specific absorption rate. Often thought to monitor levels of radiation emitted by mobile phones, it is actually the unit of measurement for the amount of radio frequency (RF) absorbed by the body when using a mobile (wireless) phone. It is used by regulatory bodies and phone manufacturers alike, for the former it is used to monitor emissions and for the latter to sell their products (a low SAR rating is good for sales).
Q. How would I find out the SAR rating for my mobile phone
A. It should be included in your user manual, otherwise you can contact the Federal Communications Commission, the telecommunications regulatory body in the US, its website includes SAR information on all mobile phones in the international marketplace. Its Wireless Telecommunications Bureau website address is http://wireless.fcc.gov/ and www.fcc.gov/oet/fccid.
Q. How are phones tested for their SAR level
A. All mobile phones are tested, in laboratories, at their highest power levels for their SAR rating. A normal call will usually be below a recommended SAR level because the mobile network is designed to use only the power needed to reach a network, which means in real terms that if you're near a base station then the power you use (and that which is absorbed by your body) is very low, whereas if the network is pushed to its limit to connect your call (you're in the middle of nowhere but can still get a signal to use your phone) then the SAR level will be higher.
Q. Do SAR rates differ on every model of mobile phone
A. Yes, they will all be slightly (occasionally markedly) different.
Q. Are SAR levels and the means of testing them accepted internationally
A. They were until the end of 1999, when solely testing a phone on its thermal (heat) emissions, calculated under its RF frequency, began to be challenged. A well-respected report published in 2000 by the University Complutense in Madrid, Spain stated that current methods of calculating mobile emissions substantially underestimated the effects on human tissue.
Q. How did this affect the regulatory position in the UK
A. As a result of this, and a lot of other research, the British government reversed its health approval recommendations on mobile phones. Until then its position had been to recommend the use of hands-free headsets to reduce radiation levels, but as research demonstrated this could actually concentrate more radiation towards the brain and could represent a greater health risk than holding a phone against your head, it changed its mind - not because it totally disbelieved all the SAR data but because it had been proved to be flawed.
Many scientists now believe that SAR standards and ratings should not be relied upon solely because they are reached in simulated, not real, test situations.
SAR tests are theoretically acceptable human body radiation absorption rate simulations that measure temperature (thermal) increases, rather than actual phone radiation emissions in decibels (dB). To date, the effects of phone radiation upon cells and biological mechanisms in the body are being debated worldwide, as are the SAR standards themselves.
Q. Isn't it more dangerous for children, with regard to radiaton emissions, to use mobile phones
A. Yes it is believed that children are more vulnerable because their skulls are not fully fixed, their nervous system is not fully developed and that they are likely to be exposed longer during their lifetimes to mobile phone radiation. A report issued by the Independent Expert Group on Mobile Phones in January 2002 advised against frequent use of mobiles by children and young adults, recommending the use of text messaging as an alternative.
The report's findings and its further research are supported by the UK government. The health secretary, Alan Milburn, has written to the chief executives of mobile phone shops throughout the UK, reminding them to ensure that all customers get official guidance on the use of mobile phones.
Further information on the health issues surrounding the use of mobile phones is available online from the following sites:
World Health Organisation site on mobile phones and health related issues.
Mobile phone health research project
Independent Expert Group on Mobile Phones
http://bmj.com/cgi/content/full/318/7196/1495
British Medical Journal follow-up on a BBC Panaroma programme about mobile phone use and radiation.
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By Karen Anderson
