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Soot is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. It is more properly restricted to the product of the gas-phase combustion process but is commonly extended to include the residual pyrolysed fuel particles such as coal, cenospheres, charred wood, and petroleum coke that may become airborne during pyrolysis and that are more properly identified as cokes or chars. Soot is theorized to be the second-largest cause of global warming.〔 * *〕 == Sources == Soot as an airborne contaminant in the environment has many different sources, all of which are results of some form of pyrolysis. They include soot from coal burning, internal-combustion engines,〔 power-plant boilers, hog-fuel boilers, ship boilers, central steam-heat boilers, waste incineration, local field burning, house fires, forest fires, fireplaces, and furnaces. These exterior sources also contribute to the indoor environment sources such as smoking of plant matter, cooking, oil lamps, candles, quartz/halogen bulbs with settled dust, fireplaces, exhaust emissions from vehicles, and defective furnaces. Soot in very low concentrations is capable of darkening surfaces or making particle agglomerates, such as those from ventilation systems, appear black. Soot is the primary cause of "ghosting", the discoloration of walls and ceilings or walls and flooring where they meet. It is generally responsible for the discoloration of the walls above baseboard electric heating units. The formation of soot depends strongly on the fuel composition.〔Seinfeld, John H. ; Pandis, Spyros N. Atmospheric Chemistry and Physics - From Air Pollution to Climate Change (2nd Edition).. John Wiley & Sons.〕 The rank ordering of sooting tendency of fuel components is: naphthalenes → benzenes → aliphatics. However, the order of sooting tendencies of the aliphatics (alkanes, alkenes, and alkynes) varies dramatically depending on the flame type. The difference between the sooting tendencies of aliphatics and aromatics is thought to result mainly from the different routes of formation. Aliphatics appear to first form acetylene and polyacetylenes, which is a slow process; aromatics can form soot both by this route and also by a more direct pathway involving ring condensation or polymerization reactions building on the existing aromatic structure.〔 *Graham, S. C, Homer, J. B., and Rosenfeld, J. L. J. (1975) "(The formation and coagulation of soot aerosols generated in pyrolysis of aromatic hydrocarbons )", Proc. Roy. Soc. Lond. A344, 259-285. *Flagan, R. C., and Seinfeld, J. H. (1988) Fundamentals of Air Pollution Engineering, Prentice-Hall, Englewood Cliffs, NJ.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Soot」の詳細全文を読む スポンサード リンク
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