HEALTH FACTORS AFFECTING THE ROUTE SELECTION / INSTALLATION OF THE PROPOSED 110kV LINE FROM LYTTON BULK SUPPLY SUBSTATION TO FISHERMAN ISLAND SUBSTATION
Volume 15 No.1 2004 National Radiological Protection Board (United Kingdom)
Particle Deposition in the Vicinity of Power Lines and Possible Effects on Health: Report of an Independent Advisory Group on Non-ionising Radiation and its Ad Hoc Group on Corona Ions
Airborne particles having the greatest effects on health include radon decay products, chemical pollutants, spores, bacteria and viruses…Since charged particles are more likely than uncharged particles to be deposited when close to the walls of the airways or the skin, an increase in the proportion that are charged could lead to an increase in adverse health effects. Such an increase could arise from the generation of corona ions by power lines (8:6).
The extent of any effect of corona ions on health will depend upon the extent of any increase in exposure to pollutants, the extent to which these pollutants are causes of disease, and the numbers and types of individuals who are exposed (16:8).
Health effects of airborne particulate pollution
The two long-term adverse health effects that have been clearly identified are cardiorespiratory disease and lung cancer (38:13).
It has been shown that daily fluctuations in outdoor concentrations of particulate matter (most often measured as PM10, that is particles of less than 10 µm diameter) are associated with changes in morbidity and mortality from both cardiac and respiratory disease (EPAQS, 2001) (41:14).
It is clear from experimental data that clouds of positive and/or negative ions may be produced by AC power lines and transported downwind…There is no doubt that the mobile negative ions attach to and thus charge pollutant particles in the atmosphere (83:24).
Deposition of 0.02 and 0.125 µm particles with a single charge was two to three times greater than that of particles with equilibrium distribution of charge, and five to six times greater than for particles with no charge (Cohen et al, 1998) (99:31).
Thus there is potential for electrostatic charge effects to increase total respiratory tract deposition and lung deposition by a large factor, about three-to ten-fold, over a limited size range, essentially between about 0.1 and 1µm, where deposition is normally low (106:33).
The PAH air concentrations in urban areas are typically three to four times those in rural areas, so any effect of corona ions on pollutant intake there could be significant (110:35).
In the light of the review above, some increase in lung deposition of particles of these sizes is likely in some circumstances as a result of charging by corona ions (112:35).
The average impact at a population level would be far lower because only a small proportion of people live in areas of high particulate pollution that are also close to sources of corona ions (144:44).
It is unclear exactly how the contribution to risk from PM10 is distributed across the different size fractions of particles, but the maximum increase in lung deposition of particulate carcinogens at any time, because of corona ions, is unlikely to be more than three-or four-fold, and probably less (146:44).
Overall Summary and Conclusions
As a consequence of corona discharges, high voltage AC power lines may produce clouds of negative or positive ions that are readily blown downwind. An increase of charge density downwind of power lines is well established and can be measured at distances up to several kilometres. The ion clouds charge pollutant particles that pass through them…The presence of corona ions could influence the uptake of pollutants by increasing their deposition in the lung or on the skin (152:45).
People may be exposed to these more highly charged pollutant particles and the effect of electrostatic charge on increasing respiratory tract deposition has been recognised for some time (153:45-6).
Henshaw and Fews (2001) have calculated that people downwind of power lines in corona might have 20%-60% more particles deposited in their lungs than those upwind. This estimate is for people exposed out of doors to pollutant particles which originate out of doors. When outdoor air enters houses, many of the pollutant particles, will be carried with it (Liu and Nazaroff, 2003), so a similar effect would be expected indoors (156:46).
The increase in pollutant deposition in the lungs seems likely to be highest in areas of the country downwind of power lines where there are high levels of airborne particulate pollution and also where the power lines are continuously in corona (157:47). The information reviewed suggests that some increase in lung deposition of pollutant particles seems likely as a result of charging by corona ions (158:47).
CSIRO Media Release -Ref 2004/31 -Mar 02 , 2004
Australia's air pollution death toll is higher than fatalities from road accidents. So air quality scientists, medical researchers and Government agency representatives from around Australia are meeting in Melbourne this week to tackle the health problems associated with air pollution.
Queensland Government – Environmental Protection Agency
http://www.epa.qld.gov.au/environmental_management/air/air_quality_monitoring/air_ pollutants/airborne_particulates/ (accessed 27/02/04)
There have been extensive studies into the health effects of different levels of particles and pollution mixes. However, no studies have yet determined a threshold value for long-term or short-term exposure below which no adverse health effects are observed.
Australian Govt, Dept of Environment and Heritage National Pollutant Inventory
http://www.npi.gov.au/ (accessed 21/03/04).
2002 – 2003 Substance Emissions Report – All Sources
PM10 pollutant particle emissions in Wynnum postcode area 4178 — 400,000 kg per year
PM10 pollutant particle emissions in Manly postcode area 4179 — 3,700 kg per year
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