A mobile phone works as a small radio, transmitting and receiving radio waves. |During a phone call it radiates energy as digital electromagnetic waves from its aerial at a frequency of 900Mhz. The danger to our health from mobile phone signals causes concern to some people. Microwaves are used in microwaves ovens to cook food.
Can microwaves cook our bodies?
In principle they can, but the power radiated by a mobile phone is much lower than the power radiated by a microwave oven. If rats are exposed to high levels of microwaves, some of them develop cancer. The effect of low doses of microwaves on humans is unclear. Even if they do cause damage that leads to cancer,this may not result in any symptoms for decades – mobile phones have only been widely used since around 2000.
All mobile phones are tested for the amount of energy absorbed by the body when in use. This energy is called the specific absorption rate (SAR) and is measured in Watts per kilogram. In the UK the legal limit is 2W/kg and in the USA it is 1.6 W/kg.The SAR values of some phones is shown below.
| Model | SAR |
| Sony Ericson T610 | 1.21 |
| Motorola A1000 | 0.74 |
| Siemens SF65 | 0.38 |
| Nokia 9300 | 0.24 |
The risk is anyway relative. If the risk of catching a specific type of cancer as a result of using a mobile phone is multiplied by some factor, does it really matter if the risk is still small compared with other sorts of risk? The risk of getting a benign head tumour is about 1 in 100,000. Swedish research implies that this risk increases by a factor of four for mobile phone users. It is still much smaller than dying in a car accident.