Modelling and analyses do not support the hypothesis that charging by power-line corona increases lung deposition of...

The National Radiological Protection Board's advisory Group on Non-ionising Radiation has recommended further study on the effects of electric charge on the deposition of 0.005-1 microm particles in the lung. Estimates have been made regarding the integrated ion exposure within the corona plume generated by a power line and by ionisers in an intensive care unit. Changes in the charge state of particles with sizes in the range 0.02-13 mum have been calculated for these exposures. The corona plume increases the charge per particle of 0.02 and 0.1 microm particles by the order of 0.1. The ionisers in the intensive care unit produced negative ions-as do power lines under most conditions. Bacteria can carry in the order of 1000 charges (of either sign) and it is shown that the repulsion between such a negatively charged bacterium and negative ions prevents further ion deposition by diffusion charging. Positively charged bacteria can, however, be discharged by the ions which are attracted to them. The data provide no support for the hypothesis that ion exposure, at the levels considered, can increase deposition in the lung.