The Chemical World This Week
NAS WAFFLES A BIT ON AEROSOL PROBLEM "Selective regulation of CFM [chlo- I ° rofluoromethane or chlorofluorocar- I bon] uses and release is almost certain to be necessary at some time and to some degree of completeness," a National Academy of Sciences committee concludes. A companion panel on atmospheric chemistry says that "it is inevitable that CFM's released to the atmosphere do destroy stratospheric ozone." After nearly 16 months of deliberation a blue-ribbon panel of scientists convened by NAS at the request of several government agencies last week apparently sealed the fate of these otherwise innocuous chemicals—sort of. The academy commitGutowsky: less than 1 % ozone drop tee backed away from recommending an immediate ban on chlorofluoro- dicates that the long-term release of carbons, saying that more data are F-ll and F-12 at present rates will needed to assess the magnitude of the cause an appreciable reduction in the problem, a process "for which no amount of stratospheric ozone. In more than two years need be al- more specific terms, it appears that lowed." This approach is just about their continued release at the 1973 what industry, in light of some im- production rates would cause ozone to portant and still unresolved scientific decrease steadily until a probable questions, has been urging about the reduction of about 6 to 7.5% is ultimate disposition of the chlo- reached The time required for rofluorocarbon issue. the reduction to attain half of this The question was first raised two steady-state value (3 to 3.75%) would years ago by chemists F. Sherwood be 40 to 50 years." But so far the reRowland and Mario J. Molina of the duction of stratospheric ozone by University of California, Irvine. Ba- chlorofluorocarbons, says Dr. Gusically, their theory says that the towsky, "is probably considerably less chlorofluorocarbons called F-ll and than 1%." At the same time the penF-12 that are released into the lower alty for a delay of up to two years, the atmosphere in large quantities (per- committee believes, is incrementally haps as much as 1.5 billion lb annu- small, possibly no more than an ultially) are swept into the stratosphere mate 0.1% reduction in stratospheric where they are photolyzed by sun- ozone. light. Chlorine atoms thus produced Concern about ozone depletion then enter into a catalytic reaction centers on two possible consequences that gradually depletes the strato- brought about by increased amounts spheric ozone, which shields the of UV light striking the earth's surearth's surface from harmful levels face. The first is an increase in the and harmful wave lengths of ultravi- incidence of malignant melanoma, an olet light. About 75% of the chlo- often fatal form of skin cancer, and an rofluorocarbons are released as increase in basal and squamous cell aerosol propellants from spray cans, carcinomas, two less serious, but more and the balance primarily as refrig- widespread forms of skiji cancer that erants from air conditioners and re- can cause disfigurement. The ability frigerators. of UV light to produce these condiThe academy's atmospheric tions has been well studied, according chemistry panel, chaired by physical to committee member Thomas B. chemist Herbert S. Gutowsky of the Fitzpatrick, a professor of dermatolUniversity of Illinois, Champaign- ogy at Harvard University medical Urbana, largely affirms Rowland and school. Molina's theory, which is based on a The second, and potentially more mathematical model of stratospheric serious effect of increased UV radiachemistry. Says the panel report, "All tion, according to committee chairthe evidence [that] we examined in- man John W. Tukey of Princeton 6
C&EN Sept. 20, 1976
University, would be changes in the earth's climate. Although not as well understood as the skin cancer problem, climatic changes could disrupt agricultural patterns, and increased UV could be injurious to plants and animals important to agriculture. For now, the committee recommends that at least the legislative machinery for selective regulation of chlorofluorocarbons be set up since it believes that "legislative authority may not now be adequate." In addition the committee also believes that "informative labeling" should be required on all aerosol products so that consumers can make a choice between those that contain chlorofluorocarbons and those that don't. D
SPI details where plastics are used Where are plastics resins used after they leave U.S. producers for plastics fabrication and a great variety of end markets? The question is deceptively simple. The truth is, only a rough estimate of market makeup has been possible up to now for the plastics field as a whole. Certainly, some markets for resins such as polyethylene have been fairly well mapped. However, definitions and details vary widely from resin to resin. Pulling together a coherent use pattern for the whole industry has been afive-yearproject for the central authority on U.S. plastics numbers, the committee on resin statistics of the Society of the Plastics Industry, in New York City. Now SPI has released the first of what will be annual reports on major plastics markets. The first report covers 10 market areas and includes all plastics except polyurethanes. Actual data collection from resin producers was by the independent accounting firm Ernst & Ernst. The top plastics market turns out to be packaging. In 1975, packaging took 26.4% of total resin sales and captive use out of a total of 21.16 billion lb. After packaging, major markets were building and construction, 17.6%; consumer and institutional products, 13.6%; electrical and electronic, 8.4%; furniture and furnish-
