Radiowaves

Radio waves are made up of both electric and magnetic fields and are the basis for telecommunication and broadcasting systems. Antennas radiate or receive radio signals. Those that irradiate can do so in all directions for broadcasts or in narrow beams for point to point communications.

The strength of field is dependent on:

• The total radiated power - the higher the power, the stronger the field
• Radiation pattern - narrow beams contain stronger fields
• Distance from the antenna – as distance increases field strength decreases

Health Effects

The only established health effects of the body absorbing radio waves are due to partial or whole body heating which could cause tissue damage or heat stress. This occurs at frequencies above 10 MHz, with the depth of penetration decreasing with increasing frequency. At lower frequencies currents could be induce which can interfere with function of nervous system.

Metal objects near high-powered transmitters can cause burns if touched.

The current evidence for an association between exposure to electromagnetic fields and cancer is weak and no biological mechanisms have been established for such an effect. It would however be prudent to minimise exposure to the lowest practicable level whilst working with or near sources of radiowaves.

Mobile Phones

These convert sound into radio waves for transmission or reception. Handsets are used close to the body and the head of the user will absorb some of the waves. There is no evidence that this has detrimental effect but applying precautionary principles and limiting use is advised. The use of hand-held mobile phones whilst driving is prohibited (see guidance document ).

Microwaves

Microwaves are radio waves and are emitted by certain types of equipment such as open-ended wave-guides and microwave ovens.

Care must be taken when using open-ended wave-guides. Burning of the skin may occur if any part of the body is placed in the path of the beam. The eyes are particularly vulnerable and in no circumstances should one look down an open-ended wave-guide when the source of microwave power is switched on. Some microwave generating equipment may also produce X-rays.

Microwave ovens are designed to ensure that all microwave radiation is contained within the working volume. However, if damage occurs there is a possible risk to operating personnel. It is therefore necessary to arrange for periodic measurements of the radiation levels outside the oven. The Engineering Faculty Workshop has the facilities to carry out these tests and is prepared to do so on request.

Microwave ovens are also widely used in laboratories. Please refer to the specific guidance on their safe use .