6.1. Evaluative literature review of the occurrence and the propagation of corona ions

Project management: Leibniz Institute for Tropospheric Research e.V., Leipzig
Start: 1 July 2019
End: 30 September 2020

Background

The high electric field strengths at live components of high-voltage overhead lines can lead to the ionisation of air components. Particularly at sharp edges (e.g. defective components, contamination), the electric field strength can quickly exceed the critical value of approx. 30 kV/cm, and a "corona discharge" can occur.

This well-studied physical phenomenon has been an undesirable side effect of high voltage power transmission since the development of high voltage power lines. The situation of radiation protection in Germany has not been sufficiently clarified in this respect.

Among other things, uncertainties exist in the risk assessment of pollutant particles that can be ionised in ion clouds emitted by high-voltage DC transmission lines. The risk assessment to date is based on indications of possible health-relevant effects from individual studies and unconfirmed hypotheses.

Objectives

The aim of the project is to systematically process and comprehensively assess the exposure of the population to ionised pollutant particles in the effective area of high-voltage power lines and the resulting consequences for the health of the exposed population based on the current state of knowledge. With reference to relevant literature, a comparison will be made with exposure from other sources, and the influence of charge and magnetic and electric fields on the deposition of pollutant particles will be determined. Further research needs to be identified as appropriate. This serves to improve risk assessment and to inform the population.

Implementation

In the first phase of the project, the researcher will review the literature on

• the mechanisms and laws of the generation of corona ions and charging of aerosols in the effective range of high-voltage power lines,
• the short- and long-term measurements of emitted space charge zones (E-fields) and their quantitative composition of charged aerosols (including charge and size distribution and chemical properties) and ions in the effective range of high-voltage installations,
• the accumulation of aerosols, pollutants, radon after-products, and the like in the effective area of high-voltage power lines,
• the emissions of ions and charged pollutants from other industrial and technical sectors and naturally occurring levels,
• the change of physical and chemical properties of pollutants through interactions with ionised air (e.g. condensation, coagulation),
• the influence of electric and magnetic fields on the deposition and movement of charged particles,
• the influence of particle charge on deposition and effect in the human respiratory tract (in both children and adults, healthy and sick individuals, and at rest and under stress) as well as on the skin and other surfaces,
• Theoretical lung models, simulations, and calculations that include the influence of particle charge.

In the later course of the research project, statements on the exposure of the population to airborne ions and ionised aerosols in the effective range of high-voltage installations will be derived from the literature identified, and the plausibility of biological and health effects of these exposures will be evaluated.