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Chemically, black carbon or BC is a component of fine particulate matter (PM ≤ 2.5 µm in aerodynamic diameter). Black Carbon consists of pure carbon in several linked forms. It is formed through the incomplete combustion of fossil fuels, biofuel, and biomass, and is emitted in both anthropogenic and naturally occurring soot. Black carbon causes human morbidity and premature mortality.〔 In climatology black carbon is a climate forcing agent. Black carbon warms the Earth by absorbing sunlight and heating the atmosphere and by reducing albedo when deposited on snow and ice (direct effects) and indirectly by interaction with clouds, with the total forcing of 1.1 W/m2. Black carbon stays in the atmosphere for only several days to weeks, whereas carbon dioxide () has an atmospheric lifetime of more than 100 years.〔V. Ramanathan and G. Carmichael, ''Global and regional climate changes due to black carbon'', 1 Nature Geoscience 221-22 (23 March 2008) ("The BC forcing of 0.9 W m–2 (with a range of 0.4 to 1.2 W m–2) … is as much as 55% of the CO2 forcing and is larger than the forcing due to the other GHGs such as CH4, CFCs, N2O or tropospheric ozone.")〕 The term ''black carbon'' is also used in soil sciences and geology, referring either to deposited atmospheric black carbon or to directly incorporated black carbon from vegetation fires. Especially in the tropics, black carbon in soils significantly contributes to fertility as it is able to absorb important plant nutrients.〔Glaser B (2007) Prehistorically modified soils of central Amazonia: a model for sustainable agriculture in the twenty-first century. ''PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY'' B, 362, 187–196.〕 ==Overview== The term black carbon was coined by Tihomir Novakov, referred to as "the godfather of black carbon studies" by James Hansen, in the 1970s. Smoke or soot was the first pollutant to be recognized as having significant environmental impact yet one of the last to be studied by the contemporary atmospheric research community. Faraday recognized that soot was composed of carbon and that it was produced by the incomplete combustion of carbon-containing fuels.〔Faraday, M., Chemical History of a Candle, Harper, New York, 1861〕 Soot is composed of a complex mixture of organic compounds which are weakly absorbing in the visible spectral region and a highly absorbing black component which is variously called “elemental”, “graphitic” or “black carbon”. The term elemental carbon has been used in conjunction with thermal and wet chemical determinations and the term graphitic carbon suggests the presence of graphite-like micro-crystalline structures in soot as evidenced by Raman Spectroscopy. The term black carbon is used to imply that this soot component is primarily responsible for the absorption of visible light.〔Rosen, H., Hansen, A.D.A., Dod, R.L., and Novakov T., Soot in urban atmospheres: Determination by an optical absorption technique, Science, 208, 741-744, 1980〕 The term black carbon is used as a synonym for both the elemental and graphitic component of soot.〔Novakov, T., 2nd International Conference on Carbonaceous Particles in the Atmosphere, The Science of Total Environment, Vol. 36, 1984〕 It can be measured using different types of devices based on absorption or dispersion of a light beam or derived from noise measurements. 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「Black carbon」の詳細全文を読む スポンサード リンク
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