Montreal Protocol on Substances that Deplete the Ozone

Confirmation of the destmetion of ozone by chlorine and bromine from halofluorocarbons has led to international efforts to reduce emissions of ozone-destroying CPCs and Halons into the atmosphere. The 1987 Montreal Protocol on Substances That Deplete the Ozone Layer (150) (and its 1990 and 1992 revisions) calls for an end to the production of Halons in 1994 and CPCs, carbon tetrachloride, and methylchloroform byjanuary 1, 1996. In 1993, worldwide production of CPCs was reduced to 50% of 1986 levels of 1.13 x 10 and decreases in growth rates of CPC-11 and CPC-12 have been observed (151). 

Ozone Layer was signed, which set a timetable for phasing out the production and use of CFCs, including halons. The date for phaseout of the manufacture of halons according to the latest Copenhagen Meeting was January 1, 1994 (UNEP, Montreal Protocol on Substances that Deplete the Ozone Layer—Final Act 1987, 1987). 

Montreal Protocol on Substances that Deplete the Ozone Layer. The phase-out of CFCs began on Jnly 1, 1989, and by 1997, a hydroflnorcarbon, HFC134a, with zero ozone depletion potential, became the dominant refrigerant in the United States. The phase-out of CFCs in developing countries is on a slower schedule. 

United Nations Environmental Program. (1995). Montreal Protocol on Substances that Deplete the Ozone Layer— Report on the. RcBigcration, Air Conditioning and Heat Pumps Technical Options Committee. New York Author. 

Several of the commercially available 16,000 chlorinated and brominated compounds have already been regulated or harmed, CFCs, DDT and chlorinated biphenyls are typical examples. Many others are being phased out according to the Montreal Protocol on Substances that Deplete the Ozone Layer. This includes chlorinated solvents, methyl bromide and halons (e.g. CF3Br). The milder ozone destroyers, hydrochlorofluorocarbons (HCFCs) will also, eventually, be phased out. 

Montreal Protocol on Substances That Deplete the Ozone Layer, 26 1LM 1541, 1987. 

Batchelor, T. 1998. Montreal protocol on substances that deplete the ozone layer. United Nations Environmental Program. Assessment of alternatives to methyl bromide. Methyl bromide technical... 

There has been an unprecedented level of international cooperation toward banning ozone-destroying chemicals. The first major step was the signing of the 1987 Montreal Protocol on Substances That Deplete the Ozone Layer, which called for the reduction of CFC production to one-half of 1986 levels by the year 1998. However, only a few years after the protocol was ratified, in 1990, scientists confirmed that the CFC problem was much more serious than they believed in 1987 when the protocol was drafted. The protocol was soon amended to call for cessation of all CFC production by 1996. Even with the protocol in place and the continued cooperation of all signatory nations, however, the ozone-destroying actions of CFCs will be with us for some time. Atmospheric CFC levels are not expected to drop back to the levels found before the ozone hole was formed until sometime in the 22nd century. 

The Montreal Protocol on Substances that deplete the ozone layer [3] came into force on... 

This is not the only problem with CFCs. They are also significant greenhouse gases (Chapter 13, p. 212). The ozone depletion and greenhouse effects have become such serious problems that an international agreement known as the Montreal Protocol on Substances that Deplete the Ozone Layer was agreed in 1987. 

Montreal Protocol on Substances that Deplete the Ozone Layer. Amended in London, June 1990 and in Copenhagen, November 23-25, 1992. Available from . 

The Montreal Protocol on Substances that Deplete the Ozone Layer requires each signatory nation to reduce its production and consumption of the CFCs 11, 12, 113, 114 and 115 to 80% of their 1986 levels by 1993 and to 50% by 1998. Figure 8 shows that production levels of the first three of these has indeed fallen dramatically since 1988, according to data reported in Reference 109 by the major industrial producers. However, the Montreal measures will have little effect on the current levels of stratospheric CFCs, which would still continue to rise for many years, as illustrated by Figure 9 for the example of CFC-12. It would be necessary to impose an 85% reduction in order to stabilize atmospheric concentrations at their 1989 level110. Even with a total cessation of CFC emission atmospheric concentrations will not be restored to their pre-1960 levels until well... 

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). 

States would spend 160 billion per year on pollution control. In 1996 Ben Lieberman, an environmental research associate with the Competitive Enterprise Institute, estimated that in the United States the cost of the phaseout of chlorofluorocarbons (CFCs) in accordance with the 1987 Montreal Protocol on Substances That Deplete the Ozone Layer could reach 100 billion over the next ten years. Indeed chemical manufacturers had to develop eco-friendly substitutes such as hydrochlorofluorocarbon (HCFC) and hydro-fluorocarbon (HFC), which are more costly to make, and hundreds of millions of pieces of air-conditioning and refrigeration equipment using CFCs had to be discarded. 

Hence, perfluorocarbons offer environmentally-friendly alternatives to common organic solvents with the potential for long lifetimes in industrial processes and are especially suitable for long, high temperature reactions. Furthermore, they are excellent substitutes for chlorinated solvents, like carbon tetrachloride, which are being phased out under the international agreement called the Montreal Protocol on Substances that Deplete the Ozone Layer and this has been demonstrated in their use as solvents in photooxidations [29] and brominations [30] of alkenes. 

Under the agreements of the Montreal Protocol on Substances that Deplete the Ozone Layer, the production of chlorofluorocarbons (CFCs), halons and several other halocarbons has been prohibited [1,2]. Consequently, there is an interest in replacing these compounds [3]. As part of the development of such replacing compounds, it is necessary to consider and evaluate the potential environmental effects of their use, especially on stratospheric ozone [2],... 

In 1974, Rowland and Molina published their hypothesis that CFCs could lead to the depletion of stratospheric ozone. With confirmation of this theory through subsequent studies, an international agreement, The Montreal Protocol on Substances that Deplete the Ozone Layer, ° was drawn up and set in motion a timetable for the phase-out of both the manufacture and use of CFCs. Although the consumption of CFCs in inhalation products is probably insignificant in ozone depletion, representing approximately 0.4% of the worldwide CFC consumption in 1986, the pharmaceutical industry has been working since 1987 to find alternative propellants with which to replace the CFCs used in MDIs. The establishment... 

The earliest polyurethane foams were water (COj) blown. In the late 1950s CFC-11 was discovered to be an excellent blowing agent for polyurethane foams, especially low-density foams, fhe development of the Ozone Depletion Theory in the late 1970s and its further refinement in the 1980s linked CFCs to a reduction of ozone in the upper atmosphere. As a result of the concern of such ozone reduction causing an increase in ultraviolet (UV) radiation at ground level the world community produced the "Montreal Protocol on Substances that Deplete the Ozone Layer" in late 1987 (9). 

Concern about the diminishment of stratospheric ozone began more than two decades ago. Molina and Rowland (1974) proposed that the release of CFCs through human activity played a major role in 03 depletion. In 1978, the United States banned the use of CFCs as propellants in aerosol sprays. In 1987, the Montreal Protocol on Substances that Deplete the Ozone Layer was established to halt the production by industrialized countries of most 03-destroying CFCs by 2000. The Montreal Protocol was subsequently amended to change the date to 1996 (Ham, 1993). 

Montreal Protocol 1987. Montreal protocol on substances that deplete the ozone layers, 1987. 

In 1995 the Nobel Prize for chemistry was awarded to F. Sherwood Rowland and Mario Molina, physical chemists from the University of California, Irvine. In then-published ozone depletion hypothesis [1], they proposed that chlorine atoms could form high in the stratosphere. As an offshoot of this work as well as some other work, the Montreal Protocol on Substances That Deplete the Ozone Layer was signed in 1987. The treaty took effect on January 1, 1989, and has since undergone several revisions. The treaty addresses ozone-depleting compounds that contain chlorine or bromine. Fluorine is not included in the treaty because it has not been shown to harm the ozone layer. 

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