Documents of the NRPB Volume 15 (1), 3-62 (2004)
Particle Deposition in the Vicinity of Power Lines and Possible Effects on Health.

Report of an independent Advisory Group on Non-ionising Radiation and its Ad Hoc Group on Corona Ions.

Production of corona ions

Whenever high voltages are present in electrical systems there is the possibility that the high electric fields that exist close to conductors may cause electrical breakdown of the surrounding air; an effect known as corona discharge.

As a consequence of corona discharges, high voltage AC power lines may produce clouds of negative or positive ions that are readily blown downwind.

The ion clouds charge pollutant particles that pass through them.

The presence of corona ions could influence the uptake of pollutants by increasing their deposition in the lung or on the skin.

Inhalation of pollutant particles

[on the effect of corona ions and charge on deposition in the lung] There are substantial difficulties in the way of modelling such effects, making all such estimates very uncertain.

The information reviewed suggests that some increase in lung deposition of pollutant particles seems likely as a result of charging by corona ions.

The main health hazards of airborne particulate pollutants are cardiorespiratory disease and lung cancer. There is strong evidence that the risk of cardiorespiratory disease is increased by inhalation of particles generated outdoors, mainly from motor vehicle exhaust, and of environmental tobacco smoke produced within buildings. The risk of lung cancer is increased by particulate pollution in outdoor air, and by radon decay products and environmental tobacco smoke in buildings.

The potential impact of corona ions on health will depend on the extent to which they increase the dose of relevant pollutants to target tissues in the body. It is not possible to estimate the impact precisely… However, it seems unlikely that corona ions would have more than a small effect on the long-term health risks associated with particulate air pollutants, even in the individuals who are most affected. In public health terms, the proportionate impact will be even lower because only a small fraction of the general population live or work close to sources of corona ions.

Deposition on the skin

There is experimental evidence … supported by theoretical analysis that the deposition of both radon decay products and chemical pollutants on surfaces are somewhat larger under power lines.

However, the physical situation is very complicated and it seems unlikely that it can be modelled with sufficient accuracy to provide reliable information in the foreseeable future.

Any health risks from the deposition of environmental particulate air pollutants on the skin appear to be negligible.

Recommendations for further research

The possible implications for health of the mechanisms discussed in this report do not provide a strong case for further research in this area.