Landfill gas is a complex mix of different gases created by the action of microorganisms within a landfill. Landfill gas is approximately forty to sixty percent methane, with the remainder being mostly carbon dioxide. Trace amounts of other volatile organic compounds (VOCs) comprise the remainder (<1%). These trace gases include a large array of species, mainly simple hydrocarbons.Landfill gases can potentially influence climate change. The major components are CO2 and methane, both of which are greenhouse gas. Methane in the atmosphere is a far more potent greenhouse gas, with each molecule having twenty five times the effect of a molecule of carbon dioxide. Methane itself however accounts for less composition of the atmosphere than does carbon dioxide .. Landfills are the third largest source of methane in the US.