Soot samples were extracted from a swirl-stabilized, liquid-fuel fired laboratorycombustor to (i) assess the validity of the ASTM smoke point test in predicting thesooting characteristics of fuels in complex combustion systems and (ii) assess theeffect of fuel molecular structure and smoke suppressant additives on the physicaland chemical properties of soot. Fuels utilized were shale JP-8, iso-octane, andblends of iso-octane with either decalin, toluene, tetralin, or 1-methylnaphthalenesuch that smoke points similar to JP-8 were achieved. Each fuel was separatelyblended with 0.05 percent (by weight) ferrocene smoke suppressant. The resultsindicate that the ASTM test can be misleading, increased fuel molecular complexityincreases soot content of higher molecular weight polycyclic aromatics, andferrocene additive reduces small particle number density but not necessarily the sootmass loading. © 1984 by ASME.