ID Number		1205
Study Type		Engineering & Physics
Model		Corona ions (small ions) emitted into the atmosphere around high voltage power lines are measured and characterized for their potential contribution to pollution
Details		High voltage powerlines ionise the air, emitting so-called corona ions (small ions) into the atmosphere. These attach to, and increase the charge state on, aerosol-sized particles of air pollution. Corona ions and charged particles can be carried several hundred metres from the powerlines by the wind (Fews et al 1999, 2002). When inhaled, charged particles have a higher probability of deposition in the lung compared with uncharged particles. Corona ions therefore mediate increased exposure to air pollution. We have estimated the possible magnitude of increased air pollution related illness associated with living near powerlines in the UK (Henshaw 2002). To compare simultaneously the size spectrum of small ions and charged aerosols upwind and downwind of powerlines, four high resolution state-of-the-art spectrometers are in various stages of construction, two each to cover respectively the size range 0.4 to 30 nm and 20 nm to 1 m. The small ion spectrometers (0.4 V 30 nm) have been constructed and can operate near to 100% relative humidity outdoors. One of the larger spectrometers (20 nm V 1 m) is currently undergoing trials. The devices are novel extensions of a Gerdien aspiration condenser consisting of a single cylindrical capacitor divided into three electrically insulated sections. The current arriving at the central section is measured by an electrometer and represents the ion flux over a known range of mobilities determined by the applied voltage. High-resolution mobility spectra are obtained from the recorded ion signal and the instrument response function using a maximum entropy procedure. Measurements will be presented of typical background ion spectra outdoors away from powerlines and for comparison, similar spectra obtained near powerlines. To assess the probability of lung deposition of inhaled charged aerosols, a mechanical model of the human lung has been constructed. Measurements will be presented of deposition of particles upwind and downwind of powerlines.
Findings		Not Applicable to Bioeffects
Status		Completed With Publication
Principal Investigator		University of Bristol, UK - peter.fews@bristol.ac.uk
Funding Agency		DOH, UK
Country		UNITED KINGDOM
References		Fews, AP et al. Int J Radiat Biol, (1999) 75:1523-1531 Fews, AP et al. Atmospheric Research , (2002) 63:271-289 Henshaw, DL Medical Hypotheses , (2002) 59:39-51
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