Atmosphere Chemistry Essay Research Paper Topic Atmosphere

Atmosphere Chemistry Essay, Research Paper

Topic: Atmosphere Chemistry

Pollution has always been an emotive irrespective of whether it occurs in the air, on land or at sea. In the latter half of this century much attention has been drawn to air pollution caused by modern methods of communication, although some cradles of the Industrial Revolution must have experienced local levels of high pollution quite unimaginable by present standards. Campaigns against the more widespread effects of atmospheric pollution are constantly mounted by the media, of which the printed word is only a part; meanwhile scientific knowledge still advances on all fronts. This greater appreciation allows a more fundamental understanding of the consequences of pollution upon the whole environment and all those who live in it.

Atmosphere chemistry involves understanding the chemical composition of the natural atmosphere, the way gasses, liquids, and solids interact with each other and how human activities may be changing the chemical and physical characteristics of the atmosphere. The difficulty is making out what it all means and what the consequences are to all of us and to the world in which we live.

The enhancing of the Green House Effect, air pollution and the depletion of the Earth s Ozone Layer are the major hazards/consequences that the human race has put on itself over the last one hundred years for revolutionizing into a much more sophisticated society. Fossil fuels such as crude oil or petroleum, coal, natural gas are burnt to provide society with the adequate energies, communication, and transport we need to keep extending and functioning. By burning these fossil fuels, a variety of pollutants are emitted (Carbon dioxide, oxides of Nitrogen, Hydrocarbons, Chlorofluorocarbons (CFC s), and Sulfur dioxide) into the Earth s Troposphere/Stratosphere. These pollutants are altering the characteristics of the Earth s atmosphere, thus having an effect on all life forms upon the Earth. The problems associated with the changes in our atmosphere include acid rain, photochemical smog, changes in the carbon and nitrogen cycles, and the Greenhouse effect.

Acid rain

When coal is burnt, for example in a smelting plant, it releases sulfur in to the atmosphere and combines with the oxygen molecules in the atmosphere to produce sulfur dioxide and sulfur trioxide.

S (in coal) + 02 SO2 (sulfur dioxide)

2SO2 + O2 2SO3 (sulfur trioxide)

When sulfur dioxide and trioxide gasses are in the atmosphere they combine with water to form sulfurous and sulfuric acid. Oxidation also occurs in the clouds and in heavily polluted air where other compounds such as ammonia and ozone help to catalyze the reaction, converting more sulfur gasses into acids.

The carbon cycle

The carbon in the atmosphere is continually recycled. The movement of carbon to carbon dioxide in the air through living things and back into the air is called the carbon cycle. Other gasses, including methane, carbon monoxide, and chlorofluorocarbons, are also found in the atmosphere.

The CO 2 is removed from the atmosphere and stored by plants (as starch and cellulose), by the ocean (which is able to dissolve some CO2), by carbonate rocks (most often shelled marine animals) by other animals (which eat plants) and by fossil fuels. CO2 is returned to the atmosphere by combustion of carbon compounds and by respiration.

These sources of carbon are called sinks or reservoirs, and represent a long-term store for carbon. By burning fossil fuels humans are releasing enormous quantities of carbon dioxide into the atmosphere in a very short time span. Such action alters the balance between the carbon reservoirs and may ultimately impact on global climate patterns.

The nitrogen cycle

The movement of nitrogen from the air and nitrogen compounds from the soil, through living things, and then back into the air and the soil is called the nitrogen cycle. The nitrogen cycle is dominated by reaction involving biological material by the following series of changes. Oxides of nitrogen: Firstly natural inorganic reaction mechanisms do not produce ammonia from nitrogen. However, high temperatures (caused by lighting, bush fires, and by car engines and industrial furnaces) can cause nitrogen and oxygen to combine to form oxides of nitrogen.

Humans have altered the balance of the nitrogen cycle through the wide spread planting of leguminous plants and the large-scale fixation of nitrogen in the manufacture of inorganic fertilizers such as ammonia (NH3), and ammonium nitrate (NH4NO3). The consequences are that these nitrates react with water vapor in the atmosphere causing an acidic solution, thus producing acid rain.

Unburnt hydrocarbons and photochemical smog

Evaporation of solvents and fuels, as well as incomplete combustion of fossil fuels, cause a different wide range of hydrocarbons to be released into the atmosphere. By far the greatest global problem with unsaturated hydrocarbons is their ability to promote the formation of photochemical smog in the presence of oxides of nitrogen, strong sunlight and stable meteorological conditions. The reaction chains involved in photochemical formation may be long and complicated because one reaction involving a free radical often generates another, which in turn reacts to generate a t

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