OZONE DEPLETION POTENTIALS ODP

The contribution of individual compounds to ozone depletion is characterized by the ozone depletion potential (ODP). The ODP of a compound as normally defined is the ratio of the global loss of ozone (i.e., integrated over latitude, altitude, and time) from that compound at steady state per unit mass emitted relative to the loss of ozone due to emission of unit mass of a reference compound, usually taken as CFC-11 (CFC13) (Wuebbles, 1983 Fisher et al., 1990 Solomon et al., 1992). The ODP thus provides a relative measure of the overall impact of a compound on ozone destruction over the long term. Values for ODPs have been derived using a variety of models (e.g., see World Meteorological Organization, 1995, 1999). 

However, the time scale for contribution to ozone depletion is not the same for all compounds (Fisher et al., 1990). For example, CFC-11 does not react in the 

A semiempirical approach has been developed by Solomon et al. (1992) and applied to the estimation of ODPs on both short and long time scales. The ODP of compound X is calculated from Eq. (A) (Solomon and Albritton, 1992)  

The ratio Fx/FCFC n is the fraction of the compound X that has been dissociated in the stratosphere compared to that of CFC-11, determined from atmospheric measurements. This term is most important at short times, i.e., right after release of the compound, in terms 

The total atmospheric lifetime of a compound is the time required for a pulse emitted into the atmosphere to decay to /e of its initial value (see Chapters 5.A.lc and 12.C). It can be calculated from 

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The cap is the percentage of the calculated level of chlorofluorocarbons consumed in the base year plus the calculated level of hydrofluorocarbons consumed the same base year It applies only to HCFCs Calculated in the context means that the amount of each substance is adjusted by its ozone depletion potential (ODP), a measure of its potential to deplete stratosphenc ozone relative to that of CFC 11... 

Ozone Depletion Potential (ODP) Global Warming Potential (GWP) ... 

Haseley [2.4] differentiates between two categories of refrigerants The first group can be exchanged in compressor systems without changing the compressor itself, but changing the injection valves. The second group with no Ozone Depletion Potential (ODP). 

OZONE-DEPLETING POTENTIAL (ODP) OF COMMON CFCS AND HCFCS >... 

TABLE 13.3 Atmospheric Lifetimes and Steady-State Ozone Depletion Potentials (ODP) Predicted Using Either a Two-Dimensional Model or a Semiempirical Method b... 

Ozone depletion potential (ODP) Global warming potential... 

TABLE 2. Atmospheric lifetime, ozone depletion potential (ODP) and global warming potential (GWP) of CFCs, HCFCs, HFCs and halons... 

Stratospheric ozone Emission of ozone-depleting compounds (CFCs, Halons) Chemical reaction release of C1 and Br in stratosphere Catalytic destruction of ozone in stratosphere Skin and crop damage, damage to materials Ozone Depletion Potential (ODP)... 

Long lived compounds in the troposphere are transported into the stratosphere, where they decompose providing a source of inorganic stratospheric bromine [25]. Even short-lived halocarbons such as bromopropane can have significant ozone depletion potentials (ODP) due to rapid transport to the stratosphere by tropical convection [26]. Bromopropane molecules release bromine atoms 2-3 times more effectively than some CFCs would release chlorine atoms in the lower stratosphere [27]. 

The search for propellants of low or zero ozone depletion potential (ODP) has led to the identification of a number of potential compounds. A number of chemical industry consortia were established to investigate the acute toxicity of the most promising candidates under The Programme for Alternative Fluorocarbon Toxicity Testing (PAFTT). ... 

CFCs. Table 6 shows major CFCs. CFC-11 has been the representative blowing agent for both flexible and rigid urethane foams (155). The use of CFCs brought significant advantages to both flexible and rigid polyurethane foams. However, ozone-depletion potential (ODP) in the stratosphere have led to the worldwide ban of the production and use of CFCs by 1995. 

An important outcome of this work has been the formulation of the ozone depletion potentials (ODPs) for chlorine-containing fluids. Arbitrarily. CFC-11 is assigned an ODP of unity the ODPs of other fluids are normalized to that of CFC-11 on a mass-for-mass basis. Important factors in determining the ODP of a fluid include its atmospheric lifetime and the quantity of chlorine it contains. Hydrochlorofluorocarbons (HCFCs) have much lower ODPs than CFCs—a consequence mainly of the former s lower atmospheric lifetimes. Hydrofluorocarbons (HFCs), which by definition contain no chlorine, have zero ODPs. 

Table 1.7 Atmospheric lifetimes (years), global-warming potential (GWP), and ozone-depleting potential (ODP) of different fluorochemicals. The global warming potential of a material is the integrated radiative forcing over 100 years after release of 1 kg divided by the integrated radiative forcing over the same period from release of 1 kg carbon dioxide [29, 31, 32a],...

Ozone depletion potential (ODP) [46-48] Emissions to air which deplete the stratospheric ozone layer CFCs... 

Ozone absorbs ultraviolet radiation from the sun while at the same time heating the gases in the stratosphere. Ozone depletion potential (ODP) is derived from its ability to deplete the ozone layer using trifluoromethane as a standard. Ozone absorbs short wavelength ultraviolet radiation from the sun in the stratosphere, it is measured in Dobson units (DUs). One DU is equal to the amount of ozone that would be 10 pm thick under standard temperature and pressure. The average DU has been about 300 for the last few decades however, this number has decreased in recent times. 

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