The ethanol blend petrol is only marginally less polluting, Australian study shows.
The project, carried out by Orbital, the CSIRO and the Department of the Environment, Water, Heritage and the Arts, collected emissions data and used scientific models to predict the health impact of five and ten per cent ethanol blend petrols (E5 and E10 respectively).
The estimates were carried out for the Australian passenger vehicle fleet in Sydney and three other major urban centres.
The project involved:
measuring exhaust emissions (including particulate matter)
measurement of evaporative emissions examination of the formation of secondary organic aerosol
assessment of the impact of E5 and E10 on photochemical smog
assessment of the health impacts of E5 and E10
The measurement program was designed to examine vehicles representative of the current Australian light duty petrol vehicle fleet. This was achieved by choosing vehicle makes and models with highest representation in the Australian fleet, ethanol suitability and emissions control system. A representative sample of 21 vehicles from the Australian passenger vehicle fleet was selected based on the above criteria for emissions testing.
The study measured the difference in vehicle emissions between ethanol blend petrol (up to 10 per cent) and unleaded petrol under Australian conditions. The study then estimated the impact that changes in emission levels may have on the health budget, by modelling the costs of illness and death due to air pollution. The results of the study are calculated using Sydney data, which has been extrapolated to include the four major Australian cities (Sydney, Melbourne, Brisbane and Perth).
The study measured decreases in particulate matter (PM) emissions from vehicles using up to 10 per cent ethanol blends (E5 and E10). In some individual vehicles, emission reductions were measured at up to 30 per cent. However, while this is a positive finding, these figures represent a small fraction (less than a half of one per cent) of the total PM emissions in the Sydney airshed.
Results for other emissions from E5 and E10 show that some pollutants marginally increase such as oxides of nitrogen while others marginally decrease such as carbon monoxide marginally decrease.
Overall the study estimates a marginal health cost savings in the four major Australian cities from widespread use of E5 and E10. However this saving will be eroded over time as new vehicles, with improved emission control technology, enter the Australian fleet.