Pollution is any atypical contributions to the environment resulting from the activities of human beings. Air pollution results primarily from the products of combustion and industrial processes released into the atmosphere. Smoke and soot from coal burning have been a problem for over 700 years. Some have even led to loss of life. Smog is the combination of smoke and fog. The presence of fog indicates that the temperature of the air near the ground is at the dew point; and with the release of latent heat, there is a possibility of temperature inversion.
The major source of air pollution is the incomplete combustion of fossil fuels - namely, coal, gas, and oil. Fossil fuels are the remains of plants and animals and are composed mainly of hydrocarbons. Incomplete combustion could result in carbon (soot), various hydrocarbons, and carbon monoxide (CO)
2 C + O2 = 2 CO
Carbon Dioxide (CO2) combines with water forming carbonic acid (H2CO3)
CO2 + H2O = H2CO3
Complete combustion can also pollute by forming Nitrogen Oxides (NOx) Nitrogen Oxide (NO) and Nitrogen Dioxide (NO2) combines with water vapor in the air to form nitric acid (HNO3)
Photochemical smog results from chemical reactions of hydrocarbons with oxygen in the air and other pollutants in the presence of sunlight, which supplies the energy. Being first identified in Los Angeles, it is often referred to as Los Angeles smog. These smogs contain many dangerous contaminants, which may be carcinogens. They can also corrode and decompose certain materials.
Sulfur, often present in fossil fuels combines with oxygen and water to form sulfuric acid (H2SO4). Although rain is slightly acidic, sulfur and nitrogen oxides cause it to be more acidic forming acid rain. a pH as low as 1.4 has been recorded. (pH of pure water is 7) Most fish species die at a pH of 4.5 to 5.0
The relative sources and magnitudes of various atmospheric pollutants
are given in the table below
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For more details of Atmospheric Pollution click here: Atmospheric Pollution
From 1880 to 1940 the average annual temperature increased by about 0.6 degrees C or 1.1 degrees F. Since 1940, the average temperature has decreased by 0.3 degrees C or 0.55 degrees F. But in the last decade, it has started rising again, with the warmest temperatures recorded in the last three years. This spring (2000) was the warmest spring since records were kept.
Global climate is sensitive to atmospheric contributions that affect the radiation balance of the atmosphere. They include concentrations of carbon dioxide and other "greenhouse" gases, which affect the Earth's albedo. Particulate pollution contributes to changes in the Earth's thermal balance. Computer models of atmospheric chemistry suggest that the acid aerosols cause a thinning of the Earth's protective ozone layer allowing more ultraviolet radiation to reach the ground.
For more on the Ozone hole, click here: The Ozone hole
Recent studies predict that the atmospheric carbon dioxide will double by the year 2065, with an increase of temperature of 1.5 to 4.5 degrees C. The possible effect of increasing temperatures include melting of polar ice caps, causing an increase in sea levels leading to flooding of low lying coastal areas.
For more information on global warming, click here: Global warming
For more information on greenhouses gases, click here: Green House Gasses Greenhouse gases
Supersonic transport (SST) aircraft operating in the lower stratosphere
release particulates and gaseous emissions.
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