LETTERS Air pollution Dear Sir: Mr. Alex Hershaft properly pointed out the inadequacies in current knowledge necessary for meaningful employment of his model, “Air Pollution Damage Functions,” (fS&T, October 1976, p 992). I realize that he intended only to illustrate, by example, the means of assessing the impact of SOn on health. He made an error, however, in suggesting that alterations in the mean death rate of Figure 3 (which is based on daily SO2
levels) can be related to changes in the annual SO2 levels of Figure 4 and the primary standard of 80 yglm3. Use of such simplification to demonstrate a principle is understandable, particularly when the author acknowledges the shortcomings. I am concerned, however, that we soon may read or hear unqualified statements-attributed to Mr. Hershaft and your prestigious publication-that “a recent study has shown SO2 is causing 6000 to 10 000 deaths per year
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Environmental Science & Technology
in the U.S.“ I have seen it happen too often! W. H. Megonnell National Association of Electric Companies Washington, D.C. 20036 Air pollution Dear Sir: William Megonnell has correctly assessed the thrust of the article and the role of Figures 3 and 4 in illustrating the potential uses of damage functions, and his caveat is well advised. On the other hand, Samuel Morris, who kindly provided some of the inputs for this project, has missed this point and chose to belabor the obvious shortcomings of SO2 damage functions that are well documented in my full report. As a matter of fact, there are several things wrong with the SO2 damage function in the article. Robert Buechley, who provided the basic data, no longer believes that there exists a direct relationship between SOn levels and excess mortality. Reductions in New York City’s SO2 levels in recent years did not produce a corresponding decrease in excess mortality, though the correlation between daily SO2 levels and daily excess mortality has persisted. Consequently, Buechley now believes that relative variations in SO2 levels are indicative of certain precursory meteorological conditions that are responsible for precipitating corresponding variations in daily mortality. Moreover, as Harold Kandiner of Allied Chemical Corporation has pointed out in a private communication, the function in Figure 3 has been plotted incorrectly, further damaging any residual utility it may have had in predicting excess mortality. Again, I should remind your readers that the thrust of both the full report (available from NTlS as PB 251519) and the more popular article that has been drawn from it are concerned with the state of the art and potential utility of damage functions as a tool in formulating public policy. The validity of any particular damage function is really quite beside the point. I regret my choice of the function in Figure 3 as one of the illustrations for the article (it does not appear in the full report) and any misleading inferences that your readers may have drawn therefrom. Finally, in submitting my original manuscript, I neglected to mention that the views expressed are my own and do not necessarily reflect the policies and technical judgments of the President’s Council on Environmental Quality or the U.S. Environmental Protection Agency, sponsors of this project. I am pleased to do so now. Alex Hershaft Interstate Electronics Corp Arlington, Va. 22202 Airport noise Dear Sir: An author, even when his work is published, always fears that it will not be read and that if it is read it will not germinate thought. Mr. Hauck’s letter
