Sunday, October 24, 2010

Diesel Generators releases black carbon which affects plant life.

It is also hazardous to the lungs and general health.

by
Dr. Nitish Priyadarshi
Fig.1. Thick layer of black carbon deposited on the fungus. Source is nearby diesel generator.
Fig.2 Black carbon being deposited on the fungus.
Fig.3 Black carbon deposited on the fungus.
Fig.4. Black carbon deposited on leafs.
Fig.5. Dead leafs due to the impact of exhaust fumes from the diesel generator.

Above photographs shows how the black carbons released by the diesel generators affect the plants. Black carbon or soot is seen deposited on fungus. These fungus are very nearer to the exhaust pipe of the generator. Even the leaves exposed to the fumes are seen dead in the picture.

Commonly known as soot, black carbon enters the air when fossil fuels and biofuels, such as coal, wood, and diesel are burned. Black carbon is found worldwide, but its presence and impact are particularly strong in Asia.

These black particulate can affect vegetation in three ways. These are:

  • Direct deposition on leaf surfaces or other surfaces exposed to atmosphere.
  • Blocking leaf stomata and /or uptake into leaf tissues.
  • Deposition onto substrates (e.g. soil) and indirect effects via changes in substrate chemistry.

Black carbon is a potent climate forcing agent, estimated to be the second largest contributor to global warming after carbon dioxide (CO2).

Soot is a general term that refers to impure carbon particles resulting from the incomplete combustion of a hydrocarbon. They are classified as a "known human carcinogen" by the International Agency for Research on Cancer (IARC).

Soot or black carbon is in the general category of airborne particulate matter, and as such is considered hazardous to the lungs and general health when the particles are less than five micrometres in diameter, as such particles are not filtered out by the upper respiratory tract. Smoke from diesel engines, while composed mostly of carbon soot, is considered especially dangerous owing to both its particulate size and the many other chemical compounds present.

Between 25 and 35 percent of black carbon in the global atmosphere comes from China and India, emitted from the burning of wood and cow dung in household cooking and through the use of coal to heat homes. Countries in Europe and elsewhere that rely heavily on diesel fuel for transportation also contribute large amounts.

Diesel combustion in trucks, buses and cars emit a lot of black carbon. The particulate air pollution also commonly comes from burning firewood, indoor cooking, and biomass burning.

Black soot deposited on Tibetan glaciers has contributed significantly to the retreat of the world's largest non-polar ice masses, according to new research by scientists from NASA and the Chinese Academy of Sciences. Soot absorbs incoming solar radiation and can speed glacial melting when deposited on snow in sufficient quantities.

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