How do mobile phones emit EME?
Mobile phones are low-powered devices that transmit and receive radiofrequency (RF) electromagnetic energy (EME) signals from mobile phone base stations. Mobile phones are required to transmit signals over distances of up to 20 kilometres. In order to minimise interference and conserve battery life, a mobile phone limits its transmit power to the minimum required to maintain good contact with the nearest base station. So, as the phone moves closer to the base station, the power emitted from the phone antenna is usually reduced.
How does the ACMA regulate EME for mobile phones?
All mobile phones supplied in Australia must comply with the ACMA’s
Radiocommunications (Electromagnetic Radiation – Human Exposure) Standard 2014 (the Human Exposure Standard). The Human Exposure Standard applies the EME exposure limits set by the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) in the Radiation Protection Standard for Maximum Exposure Levels to Radiofrequency Fields – 3 kHz to 300 GHz (2002) (the ARPANSA Standard).
The ARPANSA Standard specifies exposure limits to EME that regulate the rate at which the user absorbs energy from the handset. This is known as the specific absorption rate (SAR)—the rate at which radiofrequency energy is absorbed by a specified mass of biological tissue, expressed in watts per kilogram (W/kg).
The SAR limit for mobile phone handsets in Australia is 2 W/kg of tissue (averaged over 10 grams). The limit includes a significant safety factor, with the maximum temperature rise in the side of the head for the level in the ARPANSA Standard being less than 0.1°C. Normal human temperature fluctuations typically exceed 0.1°C.
The SAR associated with mobile phones sold in Australia is below the ARPANSA limits.
How can we be confident that mobile phones are operating within the safety limits?
Mobile phones are designed to transmit at the lowest power possible to maintain good contact with the nearest base station, whilst minimising interference with other mobile phones. It is also in the interests of mobile carriers to limit EME emissions from base stations, such that interference with adjacent cells is minimised.