ABSTRACT
This chapter outlines the characteristics of gaseous and particulate aircraft emissions as well as potential technology options to reduce them. Reductions in overall emissions can be obtained by reducing the total amount of fuel burned via more efficient engine technology. Emissions from aircraft jet engines include excess oxygen, excess nitrogen, carbon dioxide (CO2), water vapor, nitrogen oxides (NOx), carbon monoxide (CO), sulfur oxides (SOx), unburned hydrocarbons, particulate matter, and other trace compounds. The formation of NOx in aircraft gas turbines that consume aviation kerosene is overwhelmingly dominated by a thermal mechanism. There are two primary NOx-controlling combustion modes that could be applicable to gas turbines: rich-burn, quick-quench, lean-burn (RQL), and lean burn. Engine design involves making tradeoffs among many requirements. The most important tradeoffs at the engine level are those between NOx and CO2 emissions, as well as the tradeoff between NOx emissions and noise.
