The impact of oxygenated fuel additives on soot emissions has been investigated in a collaborative university, industry and government effort. The main objective of this program was to obtain fundamental understanding of how changes in fuel composition can reduce soot and PAH emissions from military aircraft combustors. The research team used a suite of laboratory devices that included a shock tube, a well-stirred reactor, a premixed flat flame, an opposed-flow diffusion flame, and a high pressure turbulent reactor. The two primary additives investigated were ethanol and cyclohexanone. Fuels included ethylene, heptane, a heptane/toluene blend and JP8. With one exception, an ethylene opposed-flow diffusion flame, the addition of an oxygenated compound led to substantial reductions in soot. Modeling of the premixed flame and opposed-jet diffusion flame was used to obtain insights into the mechanism behind the observed soot reductions.