Warming potential

PVF film for pLUORJNE CO POUNDS, ORGANIC - POLY(VINYL FLUORIDE)] (Vol 11) Greenhouse warming potential (GWP)... 

Relative to CO2 on a volume basis. A more useful way to compare the relative warming potentials is to consider the lifetimes of the species and integrate the efficiencies over a fixed time interval, usually 100 years (see Ref. 8). 

Properties. The ideal substitute should have identical or better performance properties than the CFG it replaces. The ideal CFG substitute must not harm the o2one layer, and must have a short atmospheric lifetime to ensure a low greenhouse warming potential (GWP). It also must be nontoxic, nonflammable, thermally and chemically stable under normal use conditions, and manufacturable at a reasonable pnce. The chemical industry has found substitutes that match many but not all of these cntena. 

Under these provisions, EPA must list ail regulated substances along with their ozone-depleHon potenhal, atmospheric lifetimes and global warming potentials within 60 days of enactment. 

Ozone depletion polential (ODP) and global warming potential (GWP) ol various foam blowing agents. 

Global Warming Potential. This value is based on known global warming factors for gases such as N2O, CH4 and various organic solvents, expressed relative to CO2. A mass weighted summation is used as for the acidification potential. 

Ozone Depletion Potential. This is calculated in a similar manner to global warming potential and is expressed relative to CFC-11. Factors for all common gases having significant effects on the ozone layer have been calculated. 

Global warming potential (infra-red absorption) Ozone depletion A compound s ability to absorb infra-red radiation The ability of a chemical to reach the stratosphere and interact with and destroy ozone Global warming potential (GWR) Preferred CWR less than carbon dioxide) Atmospheric lifetime... 

An even more streamlined approach scores each stage of the life cycle for impact on a number of environmental indicators. Typical indicators include resource depletion, global warming potential, smog production, acidification, eutrophication, toxic waste production and biodiversity impact. Impact is estimated using a simple numerical scale. The completed matrix is used to focus attention on areas for improvement. 

Because of the different properties and lifetimes in the atmosphere associated with each of the GHGs, emissions are typically reported as teragrams (Tg), or million metric tons, of carbon dioxide equivalent, C02eq-The 100-year time horizon global warming potential (GWP) of CH4 is 25 times as potent as CO2, N2O is 298 times as potent as CO2, and the halocar-bons range from 124 to 14,800 times as potent as CO2 (IPCC, 2007). 

Each greenhouse gas differs in its ability to absorb heat in the atmosphere. HFCs and PFCs are the most heat-absorbent. Methane traps over 21 times more heat per molecule than carbon dioxide, and nitrous oxide absorbs 270 times more heat per molecule than carbon dioxide. Often, estimates of greenhouse gas emissions are presented in units of millions of metric tons of carbon equivalents (MMTCE), which weighs each gas by its GWP value, that is, Global Warming Potential. 

---