Electrical fields generated by equipment such as computers could increase the risk of respiratory infection, according to a study by Imperial College. 

The study shows that prolonged exposure to the electric fields generated in everyday indoor environments may cause an increased risk of respiratory diseases and infection from small airborne particles such as allergens, bacteria and viruses.

Imperial College found that such risks may be far higher than previously thought, but the good news is that quite simple actions can mitigate the problem.

The particles are less than one micron in size, and can be charged by the electrostatic field caused by synthetic clothing.

Once charged, the airborne particles are more likely to be deposited on skin and lung tissue, increasing the chances of infection.

Electrical fields can also create an opposite charge to that of the airborne particles to occur in the respiratory tract.

A greater deposition of these particles increases the toxic load that the body has to deal with, raising the risk of contamination, bacterial infection and the incidence of conditions such as asthma.

Furthermore, surface contamination can prove harder to remove, because charged particles are deposited at higher speeds under high-voltage electrical fields.

The particles become deformed as they crash-land on the human tissue, making them stick harder to surfaces.

These electrical fields have also been shown to significantly reduce localised concentrations of charged molecular oxygen, a type of small air ion that enhances biological function and kills harmful microbes.

Electrical field levels can also vary with the humidity levels of the air. Relative humidity below 20-30 per cent causes a marked increase in the level of fields that can be generated, thereby increasing the incidents of deposition and infection.

However, there are some simple actions which can be taken to offset the effects, such as ensuring that equipment is properly earthed, unplugging equipment when not in use, ensuring that the atmosphere indoors is reasonably humid and selecting natural materials which create lower electrical fields.

Earlier this week Essex University published the results of a three-year study into the effects of mobile phone mast radiation. The report concluded that the symptoms people blame on mast radiation must have another cause. 

The Imperial College study will be published in the Atmospheric Environment journal in August.