Exposure to radio frequency (RF) fields from mobile phones is measured through the Specific Absorption Rate (SAR) – the amount of energy from an RF field absorbed by the human body, expressed in watts per kilogram (W/kg).

SAR is the internationally accepted measure for assessing exposure to electromagnetic fields, and the SAR value, determined by standardized tests, of a specific mobile phone is shown in the product safety information that comes with the purchased phone. Many manufacturers provide this information on their websites or on the Mobile Manufacturers Forum page: http://www.mmfai.org/public/sar.cfm.

The International Commission on Non-Ionizing Radiation Protection (ICNIRP) http://www.icnirp.org/documents/emfgdl.pdf recommends a maximum SAR level of 2 W/kg for every mobile phone. All mobile phones operating below this level are considered safe for use. Some countries, such as Canada, South Korea, and the United States, have adopted lower SAR limits of 1.6 W/kg for the head and body. Mobile phones are tested to ensure compliance with SAR levels in the countries where they will be marketed.

The Federal Communications Commission (FCC) in the United States explains in its consumer fact sheet on SAR values http://transition.fcc.gov/cgb/consumerfacts/sar.html. The document states:

“SAR values are an important tool for comparing the maximum possible RF energy exposure of a particular mobile phone model, but a single SAR value does not provide sufficient information about the typical exposure levels under normal usage conditions to make a reliable comparison between different mobile phone models.”

The actual level of exposure depends on the distance between the individual and the phone and on the level of RF energy transmitted by the phone. Mobile phones always use the minimum power needed to provide service, so real exposure varies constantly depending on several factors:

• Distance between the individual and the handset
  RF fields weaken significantly even at a short distance from the phone. Keeping the phone away from the body and using a headset or speakerphone significantly reduces exposure.

• Distance from the cellular base station
  The signal from base stations weakens with distance, meaning the RF power from the phone must increase to maintain communication with the base station.

• Obstacles between the user and the base station
  If a building, hill, or other obstruction is located between the mobile phone and the base station, the signal from the base station may be weaker.

• Service being used
  A voice call causes greater exposure to RF fields than sending a text, email, photo, using the internet, watching TV, or downloading files. This is because during voice calls the phone is usually held close to the head, whereas when sending texts or emails or watching TV, the phone is held farther from the body. Also, call duration is usually longer than the time required to send a text or email, thus increasing exposure.

Vodafone requires manufacturers to measure the amount of energy released by an RF field and absorbed by the human body – the Specific Absorption Rate (SAR) of mobile devices – when used at the ear or close to the body.

The International Electrotechnical Commission (IEC) standard http://www.iec.ch/index.htm for testing mobile phones near the body was published in April 2010, but it has not yet been incorporated into European Union regulations. We have continuously advocated for its adoption at the European level. Until this standard is approved, we will continue requiring testing based on the FCC method.