Types of Greenhouse Gases

There are several types of greenhouse gases. They include:

Greenhouse Gas*	Chemical Symbol	Sources
Controlled
Carbon Dioxide	CO2	Occurs naturally. Also a by-product of burning fossil fuels (oil, coal) and biomass as well as land-use changes and various industrial processes.
Methane	CH4	Occurs naturally. Other sources are landfills, coal mines, paddy fields, natural gas systems, and livestock.
Nitrous Oxide	N2O	Generated by burning fossil fuels, in the manufacture of fertilizer and by cultivation of soils.
Perfluorocarbons (PFCs)	Various compounds	Human-made chemicals. A by-product of aluminum smelting. Also used as a replacement for CFCs in manufacturing semiconductors.
HFC’s	Various compounds	Human-made chemical. Used largely in refrigeration and insulating foam.
Sulphur Hexafluoride	SF6	Used largely in heavy industry to insulate high voltage equipment and to assist in the manufacture of cable cooling systems.
Uncontrolled
Water Vapour	H2O (gas)	Naturally occurring. Rising global temperatures may act to increase water vapour in the atmosphere..
Ozone	O3	Naturally occurring. Also created by reactions involving nitrogen oxide gases resulting from motor vehicles and power plants. Ozone at ground level and in the lower atmosphere is linked with smog and health problems. However, in the upper atmosphere, it helps to protect the earth from ultra-violet radiation and chemicals which tend to destroy ozone in the upper atmosphere are regulated under the Montreal Protocol

*Not all greenhouse gases are to be controlled under the Kyoto Protocol.