Search results
Results from the WOW.Com Content Network
Black carbon is in the air and circulates the globe. Black carbon travels along wind currents from Asian cities and accumulates over the Tibetan Plateau and Himalayan foothills. Black carbon (BC) is the light-absorbing refractory form of elemental carbon remaining after pyrolysis (e.g., charcoal) or produced by incomplete combustion (e.g., soot).
Worker at carbon black plant, 1942. Carbon black (with subtypes acetylene black, channel black, furnace black, lamp black and thermal black) is a material produced by the incomplete combustion of coal tar, vegetable matter, or petroleum products, including fuel oil, fluid catalytic cracking tar, and ethylene cracking in a limited supply of air.
The pollutant species black carbon appears gray or black due to the absorption of electromagnetic energy by partially mobile electrons in the graphitic microstructure of the black carbon particles. This absorption is purely ‘resistive’ and displays no resonant bands: consequently, the material appears gray rather than colored.
The United Nations has raised concerns about the amount of black carbon and methane produced from open burning as a method of waste disposal. [2] Many cities and regions suffer with air pollution and low air quality as a direct result of open burning of waste. [3] [4] [5]
Created Date: 8/30/2012 4:52:52 PM
However, coal use is responsible for the majority (60 to 80%) of black carbon emissions in Asia and Africa, while diesel combustion produces 70% of black carbon in Europe and The Americas. [42] Black carbon in the lower atmosphere is a major contributor to 7 million premature deaths caused by air pollution every year. [43]
Black carbon in the Asian Brown Cloud may be reflecting sunlight and dimming Earth below but it is warming other places by absorbing incoming radiation and warming the atmosphere and whatever it touches. [19] Black carbon is three times more effective than carbon dioxide—the most common greenhouse gas—at melting polar ice and snow. [20]
Charcoal is a lightweight black carbon residue produced by strongly heating wood (or other animal and plant materials) in minimal oxygen to remove all water and volatile constituents. In the traditional version of this pyrolysis process, called charcoal burning, often by forming a charcoal kiln , the heat is supplied by burning part of the ...