editorial
Playing the environmental numbers game It’s time for those who make measurements and those who use them to start communicating with one another
l h e average man-in-the-street, if there is such an animal, has a longstanding love affair with numbers. Percent completions, games behind, yards rushing, earned run averages, you name it, your average man will rattle it off. And now he has a new figure to relish-the pollution index. Locally, newspapers, radio, and TV publish an air pollution index-parts per million of oxidant (in the summer) or sulfur dioxide (in the winter) in the air for the previous day. We’ve often wondered what John Q. Public thinks-if he even notices-when the index makes its twice-yearly shift from one criterion of pollution to the other. If he doesn’t notice the changing basis for the index, then he is really not being much less scientific about numbers than people who ought to know better. For there is an awful lot of monkey business being played with numbers, especially now that a penchant for being at least superficially quantitative has arrived on the environmental scene. It used to be that terms like “zero tolerance,” “zero residue,” and the like really meant something useful. Now that the technology of measurement has become highly refined, “zero” is a number that can hardly be believed, let alone written into some sort of regulation. Apart from the semantic mischief that can be wreaked on even accurate numbers-a half-empty bottle can be accurately described as half full, for instance-the most dangerous aspect of numbers appears to be that they are rarely quoted with an indication of how they were measured. While such qualifications are the stock-in-trade of technical papers such as those ES&T publishes each month, it is rarely that numbers are aired i n public forums with even the slightest reference to their accuracy or applicability. Typically, one group might argue that lead in the air is’ on the increase while another maintains that it is declining. Both could be right, but we’ll never know until we discover how each
group made its measurements, where and when. Quite commonly we would find that neither group actually made any measurements but instead used someone else’s numbers. It is perhaps critically important that legislators and regulation setters recognize that there is more in a number than meets the eye. The history of regulations regarding the permissible emissions from auto exhausts is fraught with good examples of this point. Practically every time the U.S. government has recommended a new test method for a pollutant, the standard for that pollutant has had to change because every method seemed to give different results. That sampling and measurement techniques have their drawbacks is widely recognized in the technical community, of course. (See the story on ASTM’S Project Threshold on page 23 of this issue, for an example.) But it is by no means so clear that the lay public understands the situation. As an example, consider the case of carbon monoxide alerts in Los Angeles; the number of these alerts is up sharply in 1971. The simple explanation is that the concentration at which an alert is called has been reduced from 100 to 50 ppm. But an impression of rapidly rising atmospheric CO levels may remain nonetheless. If numbers are going to be used as the goals of a clean environment-and promulgation of emission limits, performance standards, and all the rest of the paraphernalia of regulatory agencies indicates that they are-then the numbers game is too important to be left to those with no knowledge of analysis and measurement. Analysts and other number-getters will have to abandon their traditional independent stances and start mixing it with the number-users. The conflict may be a bruising one, but the cause is just.
1.44 w Volume 6, Number 1, January 1972 7
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