Global ozone depletion

Finally, the idea of the coupling between nucleophilic attack and proton transfer in the reaetions just discussed provides an interpretive framework for another important atmospheric reaction, namely the hydrolysis of dinitrogen pentoxide N2O5, thought to play an important role in mid-latitude global ozone depletion. 28,29 Indeed a related mechanism was suggested in ref 5 for the low acidify condition hydrolysis. 

In the course of the review, several unique characteristics of the stratosphere will become apparent. We will identify examples of how the mechanistic details of a single reaction can dramatically affect predictions of stratospheric change into the next century. This is a particularly fascinating aspect of these studies — namely that while a reasonably complete (chemical) description of the stratosphere requires approximately 200 reactions, details of the reaction mechanism of a single process can alter predictions of global ozone depletion by more than a factor of three. 

This sensitivity of conclusion to a single reaction coupled with the needed to distill a vast number of reactions into tractable subsets, the effect of which can be interpreted and tested by observations, restricts the strategy used to test models with field observations. We seek, therefore, to distill the orchestra of reactions into a few rate limiting steps to highlight which measurements must be made to test the mechanisms central to theories of global ozone depletion. 

In the third section, we review recent developments in the field of atmospheric free radical observations so we can explore how effectively these experiments have tested our understanding of atmospheric structure. The fourth section summarizes this progress and then presents the latest predictions of global ozone depletion resulting from fluorocarbon release. Recent and important changes have been reported in this aspect of the problem. 

We present here only a sampling of the most recent data obtained by those techniques to demonstrate the emerging ability of sophisticated field experiments to challenge the more fundamental hypotheses linking chemical releases at the surface with global ozone depletion. 

Solomon S. (1992) Global ozone depletion—a review. Abstr. Pap. Am. Chem. Soc. 203(Part 2) 308-PHYS. 

Pitari, G., G. Visconti, and M. Verdecchia, Global ozone depletion and the Antarctic ozone hole. J Geophys Res 97, 8075, 1992. 

Scientific Assessment of Ocyone Depletion 1991, Report No. 25, World Meteorological Organization, Global Ozone Research and Monitoring Project, Geneva, 1991. 

The other global environmental problem, stratospheric ozone depletion, was less controversial and more imminent. The U.S. Senate Committee Report supporting the Clean Air Act Amendments of 1990 states, Destruction of the ozone layer is caused primarily by the release into the atmosphere of chlorofluorocarbons (CFCs) and similar manufactured substances—persistent chemicals that rise into the stratosphere where they catalyze the destruction of stratospheric ozone. A decrease in stratospheric ozone will allow more ultraviolet (UV) radiation to reach Earth, resulting in increased rates of disease in humans, including increased incidence of skin cancer, cataracts, and, potentially, suppression of the immune system. Increased UV radiation has also been shown to damage crops and marine resources."... 

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

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

The CFC-ozone depletion issue has demonstrated that mankind has the potential to seriously modify the atmosphere on a global scale. We need to learn much more about the environment to prevent its inadvertent deterioration by human activities. 

Although in this chapter we have focused on the potential effects of increased UV-B radiation on the Antarctic marine ecosystem, our results also have bearing on efforts to describe the effects of UV radiation on global marine productivity. However, here again, considerable uncertainties still remain in assessing the effects of ozone depletion on global production. Several authors have predicted a... 

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 Global climate change Stratospheric ozone depletion... 

A mechanism of action describes the molecular sequence of events (covalent or non-covalent) that lead to the manifestation of a response. The complete elucidation of the reactions and interactions among and between chemicals, include very complex and varied situations including biological systems (macromolecular receptors, physical phenomena (thermodynamics of explosions) or global systems (ozone depletion). Unfortunately, this level of mechanistic detail is often unavailable but recent advances in molecular toxicology and others hazards, at the molecular level, have provided valuable information that elucidates key steps in a mechanism or mode of action. ... 

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... 

Global warming and ozone depletion are the two primary global hazards associated with chemicals production and use. Chemicals that have structural features capable of absorbing infra-red radiation have the potential to contribute to global warming (see Table 2.4). ... 

The boundary for LCA is substantially broader than that for mass balancing (Introduction). Impact categories of LCA are for example global warming, ozone depletion. 

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