CFC-12

Trends

Significant production of CFC-12 began in the early 1930s for use in refrigeration. Production (and release) increased slowly but steadily until after World War II, when CFCs began to be used as propellants for aerosol sprays. Very quickly, CFC-12 production for use in aerosols exceeded that for use in refrigeration. By the late 1950s, the use of CFC-12 as the blowing agent in closed-cell foams (mostly Styrofoam®) constituted an additional significant source of release. The period from the early 1950s to the mid-1970s was characterized by essentially exponential growth in total CFC-12 release; from 1952 to 1974, for example, CFC-12 release grew at a nearly constant rate, averaging 12.2% per year. This growth was primarily due to the rapid worldwide expansion of CFC use in aerosols, although refrigerant use continued to contribute a significant fraction of the total CFC-12 release. In 1975, fluorocarbon production and release began to decline after the U.S. ban on CFCs in aerosols. By the early 1980s, however, this decline reversed, partly because of growth in aerosol production in countries not participating in the ban. In addition, CFC-12 remained the preferred cooling agent in home refrigerators and, until very recently, in automobile air-conditioners. For the period 1966-81, CFC-12 release from refrigeration grew exponentially, at an average rate of 8.5% per year. Since then, release from this end use has continued to increase, though at a slower rate, averaging ~3.6% per year for period 1982-91. By 1992, however, CFC-12 release from refrigerant use appeared to level off and decline slightly. Nevertheless, as other end uses of CFC-12 declined dramatically, release from refrigerant use constituted ~80% of the worldwide total in 1992. The recent decline in the release of CFC-12 from all sources has occurred largely in response to efforts to limit emissions of fully halogenated CFCs as prescribed by the 1987 Montreal Protocol and its subsequent revisions.

CFC 12 AFEAS Releases Graph

• CFC-12 releases, 1931-92