4. TABLE /DATA OF STUDY /INFORMATION IN VARIOUS FORMS Atmospheric lifetime and GWP relative to CO 2 at different time horizon for various greenhouse gases. Gas name Chemical formula Lifetime (years) Global warming potential (GWP) for given time horizon 20-yr 100-yr 500-yr Carbon dioxide CO 2 See above 1 1 1 Methane CH 4 12 72 25 7.6 Nitrous oxide N 2 O 114 289 298 153 CFC-12 CCl 2 F 2 100 11 000 10 900 5 200 HCFC-22 CHClF 2 12 5 160 1 810 549 Tetrafluoromethane CF 4 50 000 5 210 7 390 11 200 Hexafluoroethane C 2 F 6 10 000 8 630 12 200 18 200 Sulphur hexafluoride SF 6 3 200 16 300 22 800 32 600 Nitrogen trifluoride NF 3 740 12 300 17 200 20 700
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8. REFERENCE SOURCE Anthropogenic sources (human activity) mostly related to burning different kinds of fuel : -"Stationary Sources" include smoke stacks of power plants , manufacturing facilities (factories) and waste incinerators, as well as furnaces and other types of fuel-burning heating devices -"Mobile Sources" include motor vehicles , marine vessels, aircraft and the effect of sound etc. -Chemicals , dust and controlled burn practices in agriculture and forestry management. Controlled or prescribed burning is a technique sometimes used in forest management, farming, prairie restoration or greenhouse gas abatement. Fire is a natural part of both forest and grassland ecology and controlled fire can be a tool for foresters. Controlled burning stimulates the germination of some desirable forest trees, thus renewing the forest. -Fumes from paint , hair spray , varnish , aerosol sprays and other solvents