Handbook of air conditioning and refrigeration / Shan K

9.10 CHAPTER NINE
same effect on global warming as 4100 lb (1860 kg) of CO 2 in the first 20 years after it is released
into the atmosphere. Its impact drops to 1500 lb (680 kg) at 100 years.
Phaseout of CFCs, Halons, and HCFCs
The theory of depletion of the ozone layer was proposed in 1974 by Rowland and Molina. (The
1995 Nobel Prize was awarded to F. Sherwood Rowland, Mario Molina, and Paul Crutzen for their
work in atmospheric chemistry and theory of ozone depletion.) Network station in Halley Bay,
Antarctica, established a baseline trend of ozone levels that helped scientists to discover the ozone
hole in 1985. National Aeronautics and Space Administration (NASA) flights into the stratosphere
over the arctic and antarctic circles found CFC residue where the ozone layer was damaged. Approximately
the same ozone depletion over the antarctic circle was found in 1987, 1989, 1990, and
1991. By 1988, antarctic ozone levels were 30 percent below those of the mid-1970s. The most severe
ozone loss over the antarctic was observed in 1992. Ground monitoring at various locations
worldwide in the 1980s has showed a 5 to 10 percent increase in ultraviolet radiation. Although
there is controversy about the theory of ozone layer depletion among scientists, as discussed in
Rowland (1992), action must be taken immediately before it is too late.
Montreal Protocol and Clean Air Act
In 1978, the Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA)
of the United States issued regulations to phase out the use of fully halogenated CFCs in nonessential
aerosol propellants, one of the major uses at that time. On September 16, 1987, the European
Economic Community and 24 nations, including the United States, signed the Montreal Protocol.
This document is an agreement to phase out the production of CFCs and halons by the year 2000.
The Montreal Protocol had been ratified by 157 parties.
The Clean Air Act Amendments, signed into law in the United States on November 15, 1990,
governed two important issues: the phaseout of CFCs and a ban (effective July 1, 1992) on the deliberate
venting of CFCs and HCFCs. Deliberate venting of CFCs and HCFCs must follow the regulations
and guidelines of the EPA. In February 1992, then-President Bush called for an accelerated
phaseout of the CFCs in the United States. Production of CFCs must cease from January 1, 1996,
with limited exceptions for service to certain existing equipment.
In late November 1992, representatives of 93 nations meeting in Copenhagen also agreed to the
complete cessation of CFC production beginning January 1, 1996, and of halons by January 1,
1994, except continued use from existing (reclaimed or recycled) stock in developed nations. In
addition, the 1992 Copenhagen amendments and later a 1995 Vienna meeting revision agreed to
restrict the production of HCFCs relative to a 1989 level beginning from 2004 in developed nations
according to the following schedule:
Date Production limit
January 1, 1996 100 percent cap
Cap � 2.8 percent of ODP of 1989 CFC consumption
plus total ODP of 1989 HCFC consumption
January 1, 2004 65 percent cap
January 1, 2010 35 percent cap
January 1, 2015 10 percent cap
January 1, 2020 0.5 percent cap
January 1, 2030 Complete cessation of production
Consumption indicates the production plus imports minus exports and feedstocks. The value of
2.8 percent cap is the revised value of the Vienna meeting in 1995 to replace the original value of