Increased exposure to pollutant aerosols under high voltage power lines

Purpose: To assess increased exposure to airborne pollutants near power lines by investigating theoretically and experimentally the behaviour of Rn-222 decay product marker aerosols in the 50 Hz electric field under power lines. Materials and methods: The behaviour of aerosols in outdoor air including those carrying Rn-222 decay products was modelled theoretically in the presence of an AC field. TASTRAK alpha-particle spectroscopy was used to characterize Po-218 and Po-214 aerosols outdoors. Sampling points were chosen along a line at right angles up to 200 m from a number of high voltage power (transmission) lines. Each sampling point comprised an arrangement of mutually orthogonal TASTRAK detectors. Exposures were carried out at different power line locations in various weather conditions. Results: The model predicts a two- to three-fold increase in deposition of aerosols on spherical surfaces mimicking the human head under high voltage power lines. Experimental measurements using detectors mounted on grounded metal. spheres showed an enhanced deposition of both Po-218 and Po-214 aerosols. Enhanced Po-218 deposition on 400 kV lines ranged from 1.96 +/- 0.15 to 2.86 +/- 0.32. Enhanced Po-214 deposition on 275 kV and 132 kV lines were 1.43 +/- 0.07 and 1.11 +/- 0.21, respectively, where the latter value was not significant. Conclusions: The observations demonstrate a mode of increased exposure to pollutant aerosols under high voltage power lines by increased deposition on the body. The total (indoor+outdoor) Po-218 and Po-214 dose to the basal layer of facial skin is estimated to be increased by between 1.2 and 2.0 for 10% of time spent outdoors under high voltage power lines.