The formation of suspended particulate matter (SPM) is one of the most important matters on the environmental policy in Japan. There are many mechanisms studied about those formations. In these days, a problem on condensation dust from funnels becomes grave. Those are formed from the high-temperature gases from funnels by cooling and diluted in the air. Generally, the gases are gathered with cylinder filter paper. But the mechanism of its formation in the course of cooling in the air has not yet understood enough. In this study, we applied the TOF-SIMS to analyzing the condensation dust formed from the combustion gases of heavy oil. The results, we have found out that the most gases formed were alkanes, but its composition depends on a combustion condition, and that the condition of cooling gases was very important. (C) 2002 Elsevier Science B.V. All rights reserved.