Specific Absorption Rate

Radiofrequency radiation deposits energy in the body. The amount depends on the strength of the RF field. The various international guidelines for maximum permissible amounts of RF radiation for human exposure are designed to prevent heating, the only known consequence of the energy deposition (Ahlbom and Feychting, 2003). For details on the exposure limits, see "Primer - Wireless Phones - Exposure Limits".

The Specific Absorption Rate, or SAR, indicates the amount of energy from radiofrequency radiation (RFR) that is absorbed by the body when a wireless phone is used. It is defined as the rate of energy absorption per unit mass, and is expressed in units of watts per kilogram (W/kg). The internal SAR cannot be measured directly in the body, but is estimated by theoretical calculations.

Governments or governmental agencies in individual countries have established the maximum permissible SAR values for wireless phones. In many cases the values are based on standards recommended by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) or other independent organizations. Many countries require SAR values of a phone to be published by the manufacturer. The actual SAR of a phone while in use is usually well below the maximum permissible value, since the phone uses the least power needed to reach the nearest base station. More information on SAR is found at the following web sites:

World Health Organization. www.who.int/peh-emf
Go to the section on EMF standards. You will find a map of the world, and you can click on regions/countries to ascertain the standards that apply there for electromagnetic fields protection.

Mobile Manufacturers Forum www.mmfai.org
The MMF is an international association of radio communications equipment manufacturers. Its members include Alcatel-Lucent, Ericsson, Mitsubishi Electric, Motorola, Nokia, Panasonic, Philips, Sagem, Samsung, Nokia-Siemens Networks,  Sony Ericsson and TCL & Alcatel Mobile Phones. On the site there is a health issues section that includes SAR information on many of the models produced by these companies.

UK.
Government.www.ofcom.org.uk This site gives general information about mobile phones and health. There is more information on the website of the Health Protection Agency www.hpa.org.uk

USA.
Food and Drug Administration (FDA). www.fda.gov/cellphones/
The FDA and the Federal Communications Commission (FCC) jointly operate this site. It has a series of questions and answers covering wireless phones, radiofrequency energy, base stations, safety standards, and SAR values for phones.

Federal Communications Commission.
The FCC requires wireless phones to comply with a safety limit of 1.6 W/kg for SAR to the head. SAR information can be found at. www.fcc.gov/oet/rfsafety or at www.fcc.gov/cgb/sar/

ICNIRP. www.icnirp.de
The publications page lists reviews, guidelines, and statements published by ICNIRP. Several can be downloaded free of charge. Many countries in the world follow ICNIRP guidelines.