To ask the Secretary of State for Trade and Industry what typical levels of radiation are emitted by a mobile telephone during use; at what distance from a mobile telephone mast with a maximum licensed power of 32 dbW a person is subject to (a) the equivalent, (b) 10 per cent. and (c) 1 per cent. of this level of radiation; and whether these statistics are affected when multiple carriers are using the same mast. (137343)

I have been asked to reply.

The question is framed in terms of emissions, whereas public exposure is the real point of interest. I am informed by the Health Protection Agency's Radiation Protection Division (HPA-RPD) that it is neither straightforward nor meaningful to perform the calculation requested because of the different beam patterns formed by different types of base station antennas and mobile phones, and the consequent different spatial distributions of absorbed energy in the body. Moreover, any region around a high-powered base station site, e.g. with 32 dbW output, where localised exposure of the head could be comparable to that from using a mobile phone would not normally be accessible to the general public.

The HPA-RPD, has advised that the electromagnetic field exposure guidelines published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) should be adopted in the United Kingdom. The ICNIRP guidelines are set to avoid adverse effects of exposure on health. Mobile phone base station installations in the UK are designed to comply with the ICNIRP exposure guidelines, as are mobile phones.

Techniques for measuring specific absorption rate (SAR) in the head when a phone is held to the ear have been standardised and the information for individual handsets can be found on the website of the Mobile Manufacturer's Forum at www.mmfai.org.uk. Typically the SAR values quoted for mobile phones are in the range of 20-70 per cent. of the ICNIRP guidelines.

Ofcom (and formerly the Radiocommunications Agency) has been performing an audit involving measurements of exposure to base station signals at many different sites in the UK since 2001. The maximum exposures measured are well below the ICNIRP reference level. Information about the audit is available at

www.sitefinder.ofcom.org.uk.

In summary, it is difficult to readily compare base station exposures and mobile phone exposures because the pattern of absorption of radio energy in the body is different. In both cases, public exposure is expected to be within the ICNIRP guidelines, and by a considerable margin for base stations.