Atmosphere - Research Article from Macmillan Encyclopedia of Energy

This encyclopedia article consists of approximately 19 pages of information about Atmosphere.
This section contains 5,547 words
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Atmospheric Composition

Unpolluted air contains about 78 percent molecular nitrogen, 21 percent molecular oxygen, 1 percent argon, up to 3 percent water vapor, and a host of trace gases, including carbon dioxide, carbon monoxide, methane, nitrous oxide, helium, krypton, and radon. Oxygen is constantly released to the atmosphere by green plants during photosynthesis. Plants and animals excrete carbon dioxide during respiration. Water evaporates from the surface of the Earth and travels as a vapor through the atmosphere, eventually condensing and falling as precipitation. The atmosphere-ocean-geosphere and biosphere have maintained a natural chemical balance over many millennia, although steadily increasing anthropogenic trace gas emissions may have the potential to change this natural balance in the future.

Air pollution is produced by various natural and anthropogenic sources. Natural sources inject large amounts of particles into the atmosphere, including inorganic minerals, pollen, small seeds, bacteria, fungi, and effluvia from animals, especially insect parts. These natural particles...

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This section contains 5,547 words
(approx. 19 pages at 300 words per page)
Buy the Atmosphere Encyclopedia Article
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Macmillan Encyclopedia of Energy
Atmosphere from Macmillan Encyclopedia of Energy. Copyright © 2001-2006 by Macmillan Reference USA, an imprint of the Gale Group. All rights reserved.
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