Soot Posted on 21st December 20157th May 2021 by ThePD (The Project Definition) Soot is a black powdery or flaky substance consisting carbon dust that is emitted into air as a result of incomplete fuel combustion. Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on LinkedIn (Opens in new window) Related Posted in Substance and tagged solid. ThePD (The Project Definition) ThePD has been developing the Preferred Project Definitions based on the actual project execution and operation experiences and knowledge with the Project Language, and sharing with you daily basis.