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Source: AIE / OECD, 1990.
Contribution of Man-Made Gases to the Greenhouse Effect
The greenhouse effect is not by itself a pollutant, but the result of the combined actions of several greenhouse gases (notably carbon dioxide). The atmosphere is generally permeable to short wave radiations. Those radiations are reflected by the earth surface as infrared radiations, which greenhouse gases absorb and re-emit towards the surface. There is thus a higher capacity of the atmosphere to retain heat. The greenhouse effect is an indirect consequence of carbon dioxide (about 71% of the contribution), CFCs (3%), ozone, and HC/VOC emissions, notably methane (8%), of which transportation contributes significantly.
Gas
Potential to retain infrared rays compared to carbon dioxide
Pre-industrial era concentration (in ppm)
Actual concentration (in ppm)
CO2
1
275
346
Methane
25
0.75
1.65
CFC (R12)
20,000
0
0.0004
CFC (R11)
17,500
0
0.00023
N2O
250
0.25
0.35
Source: AIE / OECD, 1990.