LONDON — Following recent health warnings about potential risks from using mobile phones and Wi-Fi enabled computers and routers, a study to be published next month warns that electrical fields generated by equipment such as computers could increase the risk of respiratory infection.

Such fears were evaluated and studied decades ago when computers first became popular for home use, but according to researchers at Imperial College, London, 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.

Their work is scheduled to be published next month in the specialist journal Atmospheric Environment .

The team at the University's Centre for Environmental Policy suggests such risks may be far higher than previously thought, but they also stress relatively simple actions can mitigate the problem.

The scientists studies the electrical fields given off by a wide variety of household items, including computers, televisions, cookers, lamps and household wiring.

They note that the potentially harmful 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.

The research also shows that the electrical fields greatly reduced concentrations of charged molecular oxygen, which is readily absorbed by the body, enhances biological functions and can also kill harmful microbes. The easy, and in some respects obvious ways to offset the effects, the article suggests, include 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.

Despite this, the study is likely to add to the increasingly negative debate about the impact of 'electronic smog' on health, most recently from the use of Wi-Fi in schools.

Earlier this year a report published by the European Commission’s Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) concluded that further research was needed to determine the long-term impact of electromagnetic fields on health.

Last week, psychologists at Essex University, England, published results from a three-year study that concluded people who believe that mobile phone masts are making them ill are deluding themselves. This research suggested people who claimed to be sensitive to radiation from the masts could not tell when they were being subjected to them.