Soot

Soot is a mass of impure carbon particles produced by the incomplete combustion of hydrocarbons. It is considered a hazardous substance with carcinogenic properties. In its broadest sense the term covers all the particulate matter this process produces, including black carbon and residual pyrolysed fuel particles such as coal, cenospheres, charred wood, and petroleum coke classified as cokes or char, and it can include polycyclic aromatic hydrocarbons and heavy metals such as mercury. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/