Understanding and Preventing Air Pollution
Air pollution is a major problem affecting the entire world. In the United States some progress has been made in reducing air pollution through the Clean Air Acts passed by the Congress. Still there is a lot to be done. To prevent air pollution it is important to understand how the air is being polluted, how it impacts on the ecosystem and what we can do about it.
Earth is surrounded by layers of gases known as atmosphere. The layer closest to the earth is called the troposphere. It extends up to ten miles above the surface of the earth. Over the troposphere is the stratosphere which extends from ten to forty miles above the earth ( Gutnick pg. 9). Ozone is a part of the stratosphere that blocks the sun’s harmful ultraviolet rays from reaching the earth. Over the stratosphere is the ionosphere which extends up to 400 miles ( Sandak pg. 37 ). In the ionosphere, the gases are broken into individual electrically charged particles called ions ( Gutnik pg. 9 )
Air, as we know, is the mixture of gases in the troposphere closest to the surface of the earth. It is mainly composed of nitrogen (78%), oxygen (21%), carbon dioxide (0.02%), argon and other rare gases (0.08%). Air pollution takes place when undesirable gases and particles mixes with the air to cause harmful effects on living and non-living things ( Becklake pg. 6 ).
There are many types of air pollutants which can be put under three basic categories. These are - gaseous, particulates, and aerosol.
Gaseous pollutants is any harmful gas that mixes into the air. Gaseous pollutants could be divided into four major groups. These are - carbon based gases, sulfur based gases, ozone, and nitrogen based gases ( Gutnik pg. 15 ).
Carbon based gases include carbon dioxide (CO2), carbon monoxide (CO), and methane (CH4). Although carbon dioxide is found naturally in small quantity in the air, increased levels of this gas produced by the burning of fossil fuels will upset the temperature balance of the earth through the greenhouse effect. Carbon monoxide is a colorless, odorless, and tasteless gas which is emitted through the process of incomplete combustion of fossil fuel. Carbon monoxide is a deadly gas that, when inhaled, combines with the blood and renders them incapable of carrying oxygen. Methane occurs as a principal ingredient in natural gas, and is produced by the bacterial decomposition of plant and animal matters. Methane in the troposphere absorbs heat and causes greenhouse effect ( Gutnik pg. 15).
A sulfur based gas occurs mostly as sulfur dioxide (SO2) which is a colorless, tasteless, foul smelling , heavier-than-air gas. Besides naturally produced from activities of the volcanoes or decomposition of organic material in swamps, it also is produced by the burning of sulfur containing fossil fuels. Sulfur dioxide combines with water vapor in the air, forming sulfurous acid (H2SO3), a major component of acid rain ( Gutnik...