The Montreal Protocol

In 1987, at a convention in Montreal, that was organized by the United Nations Environment Programme,it was agreed to reduce the amount of CFCs by 50% by removing them from deodorants and other products. It is said that this accord has been followed and it resulted in reducing the growth rate of the hole. 

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In 1976 the United States banned the use of CFCs as aerosol propellants. No further steps were taken until 1987 when the United States and some 50 other countries adopted the Montreal Protocol, specifing a 50% reduction of fully halogenated CFCs by 1999. In 1990, an agreement was reached among 93 nations to accelerate the discontinuation of CFCs and completely eliminate production by the year 2000. The 1990 Clean Air Act Amendments contain a phaseout schedule for CFCs, halons, carbon tetrachloride, and methylchloroform. Such steps should stop the iacrease of CFCs ia the atmosphere but, because of the long lifetimes, CFCs will remain ia the atmosphere for centuries. 

Economic Aspects. The estimated worldwide production of important industrial CFCs is shown in Table 5. Trichlorofluoromethane, dichlorodifluoromethane, and trichlorotrifluoroethane account for over 95% of the total production. Between 1986 and 1991 the production of CFCs has decreased dramatically due to global adherence to the provisions of the Montreal Protocol and eventually will be phased out entirely. Estimates of the distribution by use in 1986 and subsequent reductions in use are shown in Table 6. 

In April of 1991, the U.S. National Aeronautics and Space Administration concluded that o2one depletion was occurring even faster than had been estimated, and at the third meeting of the patties to the Montreal Protocol in June of 1991, an eadiet phaseout of controlled substances was proposed. An assessment of the technical and economic consequences of a 1997 phaseout is cuttendy underway, and further acceleration of the phaseout schedule to as soon as 1995 seems likely. Many countnes already have undatetaHy banned or curbed the use of controlled substances well ahead of the Montreal Protocol timetable. As of eadyjuly 1992, there were 81 parties to the Protocol. 

Handbook for the Montreal Protocol on Substances that Deplete the Ocyone Eayer, 3rd ed.. Ozone Secretariat, United Nations Environmental Program, Nairobi, 1993. 

Finally, nitromethane has been used in large quantities as a stabilizer for 1,1,1-trichloroethane. The use of this degreasing solvent is expected to decHne and disappear under the provisions of the Montreal Protocol (116), which bans ozone-depleting substances, of which this is one. 

This high projected growth rate is driven by the expected strong growth of the HCFC-22 and fluoropolymer markets, which account for 90% of the total chloroform market. HCFC-22 is a substitute for some apphcations currendy using CFC-11 and CFC-12. It is restricted by the Montreal Protocol but will not be phased out until much later. This demand pushed chloroform production up 10% in both 1988 and 1989 (32). 

Recently several patents have been issued (16—18) describing the use of 1,2-dichloroethylene for use in blends of chlorofluorocarbons for solvent vapor cleaning. This art is primarily driven by the need to replace part of the chlorofluorocarbons because of the restriction on their production under the Montreal Protocol of 1987. Test data from the manufacturer show that the cleaning abiUty of these blends exceeds that of the pure chlorofluorocarbons or their azeotropic blends (19). 

The demand for trichloroethylene grew steadily until 1970. Since that time trichloroethylene has been a less desirable solvent because of restrictions on emissions under air pollution legislation and the passage of the Occupational Safety and Health Act. Whereas previously the principal use of trichloroethylene was for vapor degreasing, currentiy 1,1,1-trichloroethane is the most used solvent for vapor degreasing. The restrictions on production of 1,1,1-trichloroethane [71-55-6] from the 1990 Amendments to the Montreal Protocol on substances that deplete the stratospheric ozone and the U.S. 

Tetrachloroethylene was first prepared ia 1821 by Faraday by thermal decomposition of hexachloroethane. Tetrachloroethylene is typically produced as a coproduct with either trichloroethylene or carbon tetrachloride from hydrocarbons, partially chloriaated hydrocarbons, and chlorine. Although production of tetrachloroethylene and trichloroethylene from acetylene was once the dominant process, it is now obsolete because of the high cost of acetylene. Demand for tetrachloroethylene peaked ia the 1980s. The decline ia demand can be attributed to use of tighter equipment and solvent recovery ia the dry-cleaning and metal cleaning iadustries and the phaseout of CFG 113 (trichlorotrifluoroethane) under the Montreal Protocol. 

The Montreal Protocol of July 1987 resulted in an international treaty in which the industrialized nations agreed to halt the production of most ozone-destroying chlorofluorocarbons by the year 2000. This deadline was hastily changed to 1996, in February 1992, after a U.S. National Aeronautics and Space Administration (NASA) satellite and high-altitude sampling aircraft found levels of chlorine monoxide over North America that were 5i % greater than that measured over Antarctica. 

In addition, EPA must ensure that Class I chemicals be phased out on a schedule similar to that specified in the Montreal Protocol—CFCs, halons, and carbon tetrachloride by 2000 methyl chloroform by 2002—but with more stringent interim reductions. Class II chemicals (HCFCs) will be phased out by 2030. Regulations for Class I chemicals will be required within 10 months, and Class II chemical regulations will be required by December 31, 1999. 

Article 5 countries in reference to the defining article in the Montreal Protocol. 

Acknowledgement to ICI Chermcals and Polymers Limited for allowing this section to be based on the company s information note (August 1991) on the Montreal Protocol... 

Recognition of the threat of stratospheric ozone depletion posed by chlorofluorocarbons and chloro-fltiorohydrocarbons led 131 countries to sign the Montreal Protocol in 1987. Production of chlorofluorocarbons was banned as of January 1, 1996, because of their potential to further deplete stratospheric ozone. Chlorofluorohydrocarboiis will be... 

Interim replacement, contains HCFC-22, which is scheduled for phase-out under the Montreal Protocol. 

R22 is an HCFC and now regarded as a transitional refrigerant, in that it will be completely phased out of production by 2030, as agreed under the Montreal Protocol. A separate European Community decision has set the following dates. 

Perhaps the most significant recent issue for the industry was the phase-out of CFCs as blowing agents resulting from the Montreal Protocol (1987) and Clean Air Act (1990).19 These regulations mandate specific timelines for discontinuation and, since foams comprise the bulk of polyurethane applications, have prompted a worldwide search for alternatives. Hydrochlorofluorocarbons, HFCs, and hydrocarbons (HCs) are now the blowing agents of choice. Which one is... 

Most nations signed the Montreal Protocol of 1987 and the amendments added in 1992, which required the more dan-... 

An additional area of concern with respect to stratospheric ozone is possible direct emissions of NOj into the stratosphere by high-flying supersonic aircraft. This issue has come up repeatedly over the past 20 years, as air travel and pressure from commercial airlines has increased. However, despite substantial research effort to understand stratospheric chemistry, the question is complicated by the changing levels of stratospheric chlorine, first due to a rapid accumulation of tropospheric CFCs, followed by a rapid decline in CFC emissions due to the Montreal Protocol. To quote from the from the 1994 WMO/UN Scientific assessment of ozone depletion, executive summary (WMO 1995) ... 

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