Increased exposure to pollutant aerosols under high voltage power lines

Abstract

Purpose: To assess increased exposure to airborne pollutants near power lines by investigating theoretically and experimentally the behaviour of 222 Rn decay product marker aerosols in the 50Hz electric field under power lines. Materials and methods: The behaviour of aerosols in outdoor air including those carrying 222 Rn decay products was modelled theoretically in the presence of an AC field. TASTRAK alphaparticle spectroscopy was used to characterize 218 Po and 214 Po aerosols outdoors. Sampling points were chosen along a line at right angles up to 200m 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 218 Po and 214 Po aerosols. Enhanced 218 Po deposition on 400kV lines ranged from 1.96 0.15 to 2.86 0.32. Enhanced 214 Po deposition on 275kV and 132kV 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) 218 Po and 214 Po 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.