e 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 pg. 15).Ozone is a form of oxygen (O3) and a major air pollutant in the troposphere. It is very harsh and irritant to the lungs, and can be a serious problem for people with lung disorders. Ozone in the stratosphere, on the other hand, is good and acts as a filter to the suns harmful rays which can reach the earths surface, causing skin cancer to the human and damaging plant tissues ( Gutnik pg. 15). Nitrogen based gases include nitrogen oxide (NO), nitrogen dioxide (NO2) and nitric oxide (NO3). These are mainly produced by the incomplete combustion of fuel in gasoline and diesel engines, and industrial and power plants. These gases in the presence of light energy and hydrocarbon form a group of compounds called PAN ( peroxyacetyl nitrate) through photochemical process which are responsible for causing smog. They also combine with water vapors in the air to form nitric acid (HNO3) which is also a component of acid rain ( Gutnik pg. 16).Particulates that pollute the air come mos...