First Global Standard For Measurement Of Mobile Phone Exposure Developed
Geneva -- How can you be sure that your mobile telephone is safe to use when it comes to the radio frequency (RF) field it emits? Are any public health authorities or international organizations putting safeguards into place?
RF fields cause human tissue to heat up. Specific absorption rate (SAR) limits are intended to eliminate risk to human health of this effect and are set at levels well below the point where any adverse effects are known to occur. SAR limits are set by organizations such as the International Commission on Non-Ionizing Radiation Protection (ICNIRP), headquartered in Germany, and the Institute of Electrical and Electronics Engineers (IEEE), based in the United States.
Until now there hasnt been a single, globally accepted standardized measurement method for products that must adhere to SAR limits. RF emissions from similar devices vary from one product and one manufacturer to another. The SAR limit for mobile phones of 2 Watts per kilogram averaged over any 10 grams of contiguous tissue is the value used in most countries; 1.6 Watts per kilogram averaged over any 1 gram of tissue in the shape of a cube is used mainly in North America. Both are considered safe by the World Health Organization.
The International Electrotechnical Commission has just published a new International Standard that mobile phone manufacturers -- or anyone making hand-held wireless communication devices -- can use to ensure that their products adhere to internationally recognized SAR limits. It specifies the methods to use to measure SAR limits and harmonizes different practices and different methods used around the world. This standard deals only with measurement methods. It does not set SAR limits.
SAR, which was first proposed by the National Council on Radiation Protection and Measurements in 1979 as a measure of the rate at which RF energy is absorbed in a unit mass of biological tissue, is measured in units of Watts per kilogram averaged over 1 gram (IEEE) or 10 grams (ICNIRP) of tissue. SAR can be determined analytically (computer modeling) or by measurement. Using robot-controlled miniature probes to measure the electric field strength in an anthropomorphic phantom model of the human head is currently the preferred technique.
IEC Technical Officer Rémy Baillif says there has been a high demand from manufacturers for this standard. Manufacturers of mobile phones, specialized test laboratories, telecommunications regulators and health officials should constitute the largest user group of the new standard, but it is the end-user -- the consumer -- who is the ultimate beneficiary.
The World Health Organization is deeply involved in the question of RF fields and human health. As part of its charter to protect public health and in response to public concern over health effects of electromagnetic frequency exposure, the WHO established the International EMF Project in 1996 to assess the scientific evidence of possible health effects of EMF in the frequency range from 0 to 300 GHz. The EMF Project encourages focused research to fill important gaps in knowledge and to facilitate the development of internationally acceptable standards limiting EMF exposure. Ultimately, the intention is for the WHO to issue clear recommendations to its member countries so that they can enact safety legislation on this question. The IEC is a partner in the EMF Project and was encouraged by WHO to develop measurement standards for EMF emitting devices.
The new International Standard IEC 62209-1 was developed jointly by the IEC, by the European Committee for Electrotechnical Standardization (CENELEC), and by the IEEE, who worked together informally through common membership in various technical committees. This is the first of a multi-part series of standards and it covers devices, such as mobile phones, with a frequency range of 300 MHz to 3 GHz.
Source: International Electrotechnical Commission