SAR information

Mobile phone manufacturers have begun providing information about the Specific Absorption Rate (SARs) of their products.

How much radiation from mobile phones is absorbed by the user’s head? Are some models of mobile phones safer than others? What information is available to help consumers make an informed choice when purchasing a new phone?

The public’s plea for information about comparative radiation levels from mobile phones has not entirely fallen on deaf ears. Manufacturers have finally agreed to provide the information they have had all along—the SAR levels for mobile phones.

On October 1 some manufacturers began providing SAR levels for new model mobile phones sold in Australia and others will shortly follow suit. The Australian Mobile Telecommunications Association (AMTA) expects that by late March 2001 “most new mobile phones sold in Australia will include SAR information.” SAR details will be provided in the user manual or in a leaflet inside the box and most manufacturers will also provide details on their websites.

SAR (Specific Absorption Rate) is an indication of how much radiation is absorbed by the head. It is tested on a plastic model, moulded to the shape of a large male head, that is filled with a liquid designed to simulate the brain. While the mobile phone is held in position against the phantom head, sensitive probes are inserted into the liquid and the temperatures recorded. Tests are conducted with the phone operating at its highest power output.

Are SAR levels necessarily an indicator of mobile phone safety? Not necessarily. Firstly, the SAR tests assess the absorption of radiation when the phone is operating at its maximum power. However, in reality mobile phones do not always operate at their highest power level, as adaptive power control allows them to increase or decrease their power according to need.

Secondly, SAR tests measure radiation absorption in specific positions and locations. Simply adjusting the angle of the phone can make a considerable difference to the amount of radiation that is absorbed by the phantom head. Further, more symptoms have been reported by users of the low-SAR rated Motorola Startac than by users of higher-SAR phones, perhaps because the Startac emits less radiation from the region of the antenna and more from the body of the handset itself.

The text that accompanies SAR measurements in the user manual or box states that “The SAR limit for mobile phones is 1.6 watts/kg averaged over one gram of body tissue. The standard incorporates a substantial margin of safety to give additional protection for the public and to account for any variations in measurements.” While this may be true of the standard, it may not necessarily be the truth. There are concerns that it may not be appropriate to average radiation in the head and that localised heating may cause serious problems. Indeed, there are many people already claiming symptoms from mobile phone use and studies indicating adverse effects at exposures below the standard.

Professor Olle Johansson of Sweden’s Karolinska Institute, believes, “today’s recommendation values for mobile telephony, the SAR-value, are just recommendations, and not safety levels. Since scientists observe biological effects at as low as 20 microWatts/kg, is it then really safe to irradiate humans with 2 W/kg (ie, with 100 000 times stronger radiation!) which is the recommendation level for us?” (

While SAR tests may be ideal for assessing radiation in a bowl of jelly, it may be questioned whether they are necessarily an indication of what is happening inside our brains. Nevertheless, manufacturers’ willingness to provide this information to the public and the availability of a comparable rating system is certainly a step in the right direction.

EMRAA News Dec 2001, Vol 6 No 4