Technology review of aeroengine pollutant emissions

The Environmental effects issue of air traffic has been gaining increasing public attention. This has led to a considerable world-wide effort to reduce aircraft emissions. The task encompasses a broad variety of scientific and technological problems which are reviewed.The concerns about atmospheric effects have been based largely on laboratory information and experience from weather and climatic simulations. Research carried out over the past few years will improve the understanding of physical and chemical interaction phenomena and will support regulatory activities. Operational changes of airline flight profiles would be of benefit to the reduction of NO_x released into the stratosphere but would probably involve a major economic penalty. Emissions reductions through improved engine technology offer an overall potential of 10 % lower fuel burn but will also require a considerable component development effort and investment.Combustion technology appears most promising and industry is concentrating research in this area. Over the past two decades smoke emissions have become negligible and oxides of nitrogen have been reduced by 50 %. Staged combustion and emerging lean premix and rich-burn quick-quench lean-burn technologies are potentially good for another 50 % reduction. Alternative gaseous fuels will become of interest only in the context of a necessity to generally replace crude oil fuels.