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MindTouch
http://mindtouch.com

This file and accompanying files are licensed under the MindTouch Master Subscription Agreement (MSA).

At any time, you shall not, directly or indirectly: (i) sublicense, resell, rent, lease, distribute, market, commercialize or otherwise transfer rights or usage to: (a) the Software, (b) any modified version or derivative work of the Software created by you or for you, or (c) MindTouch Open Source (which includes all non-supported versions of MindTouch-developed software), for any purpose including timesharing or service bureau purposes; (ii) remove or alter any copyright, trademark or proprietary notice in the Software; (iii) transfer, use or export the Software in violation of any applicable laws or regulations of any government or governmental agency; (iv) use or run on any of your hardware, or have deployed for use, any production version of MindTouch Open Source; (v) use any of the Support Services, Error corrections, Updates or Upgrades, for the MindTouch Open Source software or for any Server for which Support Services are not then purchased as provided hereunder; or (vi) reverse engineer, decompile or modify any encrypted or encoded portion of the Software.

A complete copy of the MSA is available at http://www.mindtouch.com/msa

Sources of Sulfur Oxides

It has been estimated that on a global basis, natural sources, such as volcanoes, contribute about as the same amount of sulfur oxides to the atmosphere as human industrial activities. This amounts to 75-100 million tons from each source per year. However, in industrial countries such as in Europe and North America, human activities contribute 95 % of the sulfur oxides and natural sources only 5 %. In the Western States, natural sources of sulfur oxides may be more important.

Human Sources of Sulfur Oxides

In 1980, emissions of sulfur dioxide totaled 24.1 million tons in the United States. Of this total 66 % came from electric power companies. Electric power companies that burn coal are a major source of sulfur oxides. Other industrial plants contributed about 22 %. Smelting of metals such as copper, zinc, lead, and nickel can produce large amounts of sulfur dioxide. In Canada, 45% of the emissions are from smelting operations, compared to only 6 % in the United States.

Coal contains mainly carbon with some hydrogen. When coal is burned it reacts with oxygen in the air to produce carbon dioxide and water and large amounts of heat.

$C + O_2 \rightarrow CO_2$

In addition, coal may contain from 1-4 % of the element, sulfur. When the coal is burned with oxygen in the air, the sulfur is reacted to form sulfur dioxide.

$S + O_2 \rightarrow SO_2$

Wood Smoke

In certain resort towns, a significant source of visible smog conditions results from the burning of large quantities of wood in fireplaces and stoves. The smoke contains solid particles which may provide the initial bit of solid or catalyst that initiates the reactions to produce sulfuric acid or nitric acid in the water droplets. This is a well recognized problem in Aspen and Vail Colorado. Steps are being taken to reduce the burning of wood.

Contributors

10:43, 16 May 2014

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