Stratospheric ozone layer depletion

All other scorecard items stem directly from lifecycle analysis assessment theory (32). For some impact types, quantitative norms can be stated. For stratospheric ozone layer depletion components, the emission norm is zero. This means in practice that components such as CFCs and SF6 should not be used at all, not even in contained technical applications, because containment over the lifecycle cannot be ensured. 

Hayashi, K., Itsubo, N., Inaba, A., 2000. Development of damage function for stratospheric ozone layer depletion — a tool towards the improvement of the quality of life cycle impact... 

O Classified as a volatile organic compound (VOC). VOC can react in the lower atmosphere to form ozone and other oxidants. VOC means any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metaUic carbides or carbonates, and ammonium carbonate, which participates in atmospheric photochemical reactions. Some compounds are specifically exempted firom this definition which is found in 40 C.F.R. 51.100(s). T Considered a hazardous air pollutant (HAP) and listed in Title III of the Clean Air Act Amendments of 1990. D A regulated stratospheric ozone layer depleter. 

Comprehensive theoretical calculations have been reported for the ground and excited states of fluorobromocarbene, which is an adduct active in the stratospheric ozone layer depletion. This study correlated nicely with the previous experimental and theoretical results and revealed that the different states are interacting strongly and that the electronic states exhibit complex dynamics. 

An important effect of air pollution on the atmosphere is change in spectral transmission. The spectral regions of greatest concern are the ultraviolet and the visible. Changes in ultraviolet radiation have demonstrable adverse effects e.g., a decrease in the stratospheric ozone layer permits harmful UV radiation to penetrate to the surface of the earth. Excessive exposure to UV radiation results in increases in skin cancer and cataracts. The worldwide effort to reduce the release of stratospheric ozone-depleting chemicals such as chlorofluorocarbons is directed toward reducing this increased risk of skin cancer and cataracts for future generations. 

Ozone layer depletion, stratospheric, 21 525-529 Ozone level, reduction in, 21 528 Ozone molecules, vibrationally excited, 27 774... 

Figure 26.4 Abiotic and biotic interactions leading to the indirect toxicity of chlorofluorocarbons to amphibians. Atmospheric release of chlorofluorocarbons causes the depletion of the stratospheric ozone layer (abiotic-abiotic interaction). Depleted ozone allows for increased penetration of UV-B radiation (abiotic-abiotic interaction). UV-B radiation alone and in combination with fungus (abiotic-biotic interaction) causes increased mortality of amphibian embryos.

Depletion of stratospheric ozone layer Global warming Formation of photochemical pollutants Acidification Pluman toxicity... 

Depletion of biotic resources biodiversity Dehydration Depletion of stratospheric ozone layer Not identified Not identified... 

Ozone depletion Destruction of the stratospheric ozone layer that protects the Earth from harmful effects of ultraviolet radiation. Depletion of the ozone layer is due to the breakdown of certain chlorine- or bromine-containing compounds (chlorofluorocarbons or halons), which break down when they reach the stratosphere and then catalytically destroy ozone molecules. 

There is currently an international phaseout of the production and use of bromo- and chlorofluorocarbons because of the ability of photolytically produced chlorine and bromine to catalyze the conversion of ozone to oxygen through cyclic processes such as are shown in equations 22-24, in which X = Cl or Br95. This has led to some degree of depletion of the stratospheric ozone layer. 

By blending CFCs, it is possible to achieve appropriate vapor pressure, solvency and liquid density. However, CFCs have been linked with the depletion of the stratospheric ozone layer and will be phased out in accordance with the Montreal Protocol on Substances that Deplete the Ozone Layer . Current substitutes are the hydrofluoroalkanes (HFAs), e.g. 1,1,1,2-tetrafluoroethane (HFA-134a) and 1,1,2,3,3,3-heptafluoropropane (HFA 227) (Table 10.3). 

Oxidizer Chemical substance that causes oxygen to combine with another chemical substance examples include oxygen and hydrogen peroxide Ozone depletion Destruction of the stratospheric ozone layer that protects the Earth from harmful effects of ultraviolet radiation. Depletion of ozone layer is due to the breakdown of certain chlorine- and/or bromine-containing compounds (chlorofluorocarbons or halons), which break down when they reach the stratosphere and then catalytically destroy ozone molecules Ozone layer Protective layer in the atmosphere, about 15 miles above the ground. The ozone layer absorbs some of the sun s ultraviolet rays, thereby reducing the amount of potentially harmful radiation that reaches the Earth s surface PAHs Polycyclic aromatic hydrocarbons... 

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

Shortly thereafter, the effect on stratospheric ozone of chlorine released from human-made (anthropogenic) chlorofluorocarbons was predicted by Mario Molina and F. Sherwood Rowland. For their pioneering studies of atmospheric ozone chemistry, Crutzen, Molina, and Rowland were awarded the 1995 Nobel Prize in Chemistry. It was not until 1985, with the discovery of the Antarctic ozone hole by a team led by the British scientist Joseph Farman, that definitive evidence of the depletion of the stratospheric ozone layer emerged. 

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