Mobile Telephony and Health
Summary
There are over 65 million mobile phones being used in the UK and they continue to increase in popularity, as new features become available. Base stations and their antenna masts are needed to serve these mobile phones and the number of base stations has increased in line with the number of phones. There are around 47,000 base stations.
Key messages
Mobile Phones Base Stations
• Radiate powers up to around ¼ watt. • Radiate powers up to around 100 watts.
• Held with their antenna around 2 cm from the user’s head. • Antennas are typically tens of metres away from the general public.
• Mostly expose the tissues of the head nearest to the phone’s antenna. • Exposure is more even over the body but at a very much lower level than with a phone.
• Localised exposure is measured as the Specific Absorption Rate (SAR) of energy in the head. • The power density of the radio waves incident on the body is a good measure of whole-body exposure.
• Guidelines advise localised SAR should not exceed 2 watts per kilogram when averaged over any 10 grams of tissue and any 6 minute period. • Guidelines advise reference levels of either 4.5, 9 or 10 watts per square metre depending on the frequency band.
• All phones sold in the UK have to be tested to ensure they produce SARs below the above figure. • In addition to their obligations under UK safety law, the Network operators have voluntarily agreed to comply with international guidelines.
• SAR values for specific phone models can be found through the MMF website and range up to around 1.5 watts per kilogram. • Typical exposures at locations accessible to the public are thousands of times lower than guidelines.
These webpages provide general background information relating to the radio waves from phones and base stations, typical exposure levels of people using phones and living near base stations and relevant scientific and policy positions.