Cloudy Evidence about Air Pollution
Stark, J.
J. Stark Cloudy Evidence about Air Pollution • • Many environmentalists campaign against pollution with a moral fervor reminiscent of evangelists crusading against sin. And perhaps this tone...
...To await such an improvement before attacking environmental problems would "leave a rather large but poorly defined residual of continuing ill health...
...Despite the general cogency of their warnings about disrupting the ecological balance, and despite the value of their sensitivity for natural beauty and diversity, environmentalists can muster little solid evidence to support many of their claims...
...As for persistent cough, production of sputum, shortness of breath, and other more severe complaints, we learn that "at present there is not a substantial body of laboratory or epidemiologic evidence indicating that either photochemical oxidants or carbon monoxide constitutes a risk factor for chronic respiratory disease...
...Nor would they be surprised by as-yet-undiscovered but "substantial benefits associated with the control of carbon monoxide and hydrocarbons...
...and by 1976, a 90% reduction in nitrogen oxide emissions below the average level of 1971 cars sold outside California...
...Indeed, given the ever-expanding volume of research and the enormous publicity devoted to the environment, it is nothing short of miraculous how little is actually known about the subject--and, still more frightening for policy formulation, how little is known about how little is known...
...But no one seems to agree as to how they should be adjusted...
...and Niren L. Nagda of the University of Illinois compare five conflicting opinions as to the relative hazards presented by major air pollutants...
...While pollution is undeniably a very great evil, it is not as yet an especially well-defined one...
...Very considerably: The severity factors assigned to hydrocarbons is 2 on one scale, 124 (using the same unit) on another...
...But that, of course, was not the strategy Congress adopted, as the current reliance on oxidation catalysts demonstrates...
...That is an understatement...
...They believed that only catalyst technology could both reduce emissions to the required levels in time and protect their investments in the conventional internal combustion engine...
...The authors also intimate that they would not be surprised to find photochemical oxidants causing a wider "variety of systemic changes that constitute adverse health effects...
...J. Stark Cloudy Evidence about Air Pollution • • Many environmentalists campaign against pollution with a moral fervor reminiscent of evangelists crusading against sin...
...18 The Alternative: An American Spectator February 1976...
...By 1975, there was to be a 90% reduction in hydrocarbon and carbon monoxide emissions below the allowable level of 1970 cars...
...The 1974 annual report of the Council on Environmental Quality (CEQ) notes, "Very complex conceptual problems arise when one attempts to equate the presence of one or more pollutants with a corresponding quantitative estimate of resulting damage...
...There is a similar want of consensus as to the dangers presented by various sources of air pollution...
...And so it goes—best judgments based on tentative assumptions about imprecise and unreliable evidence, which are then denounced by opponents on equally flimsy authority...
...would result in a net public health risk...
...Though the authors of the report concede that their "best efforts allow only a roughapproximation" of benefits and risks traceable to catalysts, they urge policy-makers to forge ahead with the air pollution control effort anyway...
...On the other hand, of course, it might be asked whether the original pollutants posed such a threat as to warrant the rather rash measures legislated in the first place...
...it characterizes much of our "knowledge" about the environment...
...No one is sure of the answers—not a unique dilemma in this area...
...those for nitrogen oxides range from 22 to 100...
...Disagreement on all sorts of environmental questions is rampant in the scientific community...
...In stating that "Babcock's method probably underestimates the adverse impact of transportation sources," the CEQ's 1973 annual report acknowledges the speculative nature of such figures...
...Because equal amounts of different pollutants do unequal amounts of damage (e.g...
...They ask if it is really necessary, if the new emissions really pose such a threat to public health and property as to warrant the suspension...
...Many of those uncertainties are strikingly revealed in "Estimates of the Public Health Benefits and Risks Attributable to Equipping Light Duty Vehicles with Oxidation Catalysts," one of the studies to which the "Issue Paper" refers...
...Motor vehicle emissions constitute roughly half of all air pollutants by weight—industrial processes, solid waste disposal, stationary fuel combustion, and other miscellaneous sources supply the rest—but for what percentage of the total harm done by air pollution are they responsible...
...emissions that caused the conditions...
...In sum, Kneese and Schultze observe, "Policy making...
...Unfortunately, however, there is now evidence that in the process of removing these three pollutants from auto emissions, the catalysts actually accelerate the production of another...
...Before the era of the catalytic converter, the small sulfur emissions from cars, which were released primarily as sulfur dioxide, were of minor concern...
...In an article appearing in the Journal of the Air Pollution Control Association (March 1973), for instance, Lyndon R. Babcock, Jr...
...We are told that "laboratory studies in animals indicate that exposure to elevated levels of photochemical oxidants are likely to increase the risk for excess acute respiratory disease in man," but that "existing epidemiologic studies have not yet been able to disentangle oxidant effects from the other major determinants of such illnesses...
...the continued use of oxidation catalysts...
...More than righteous intentions are needed to justify such a great price...
...must operate in a world of imperfect knowledge, in which the relative cost and effectiveness of various abatement devices,and the interaction of pollutants with the environment, are subject to great uncertainty...
...However, responsible scientistswill not be surprised if future studies reveal a contributing role for photochemical oxidants in these disease processes" (italics mine...
...one gram of nitrogen oxide is more deleterious to health than one gram of carbon monoxide), everyone seems to agree that measurements of air pollution emissions should be adjusted according to-their effects...
...The public and policy-makers alike should be aware of this discrepancy and be duly cautious, for as laws are passed, costs escalate—most estimates for the cost of reducing automobile emissions in the late seventies to currently legislated levels hover between five billion and ten billion dollars annually...
...They rank the pollutants according to the "severity factors" assigned to them by different studies, including their own, and note that while "CO is considered least deleterious [by unit] on all scales...
...And perhaps this tone is appropriate, for environmentalists too must often rely more heavily on faith than fact to win converts...
...As Allen V. Kneese and Charles L. Schultze conclude in Pollution, Prices, and Public Policy, a different "strategy that set less rigid deadlines, tried to deal specifically with some especially bad local situations, but provided incentives for phasing out the internal combustion engine would almost certainly have been preferable and more likely to achieve longer-run objectives...
...On this very subject, however, the report offers us little information that is particularly enlightening...
...The technical literature in the field, which is saturated with qualified guesses and predictable rebuttals, reveals a startling lack of agreement as to the real dangers, sources, and even definitions of pollution...
...Yet this is the stuff that environmental laws are made on—and one cannot help but wonder if some of the lawmakers are not "rounded with a sleep" when they vote...
...Given all this doubt...
...Although the comparison of health benefits and risks is difficult to precisely quantify, the results of our recent analysis suggest that...
...It is unlikely," they argue, "that major national decisions affecting public health, energy and transportation can wait until our ability to make benefit-risk analysis of motor vehicle emissions is significantly improved...
...Citing this newly discovered health hazard (or potential health hazard), Russell E. Train, Administrator of the Environmental Protection Agency, announced in March 1975 that he would request a delay in imposing mandated emission standards until 1982 —much to the consternation of many devout environmentalists, who view the postponement as a tricky evasion, a reneging on the public commitment to clean up the air...
...This qualified conclusion is further qualified by a note that it "is based upon assumptions about dose responses and human exposure about which there still remain uncertainties...
...While it is generally accepted that heavy concentrations of carbon monoxide are a danger to human health, especially for people with heart disease and emphysema, and that hydrocarbons and nitrogen oxides produce smog which corrodes materials, irritates the eyes, engenders respiratory diseases, and aggravates heart and lung conditions, the detectable threshold of harm for any one pollutant depends on many factors—air movements, concentration of emissions, exposure, and sensitivity of the receptor...
...Problems, in other words, have been traded off—for one "solved," one has been "created...
...Hydrocarbons, carbon monoxide, and nitrogen oxides have indeed been reduced, albeit by rather inefficient, cumbersome, and generally troublesome means...
...it would seem very difficult indeed to establish effective priorities and policies for air pollution control...
...What's to be done...
...Catalysts were employed and have undoubtedly worked to a de-gree...
...Others, including the National Academy of Sciences, criticized this method as not durable or economically sound, but the time constraints diminished the possibility of more novel or experimental technology being attempted by the auto-makers...
...and Pollution, Prices, and Public Policy cites the problem of establishing "the relationship between environmental conditions in a particular location and the source of the...
...The 1970 Amendments to the Clean Air Act established stringent new limits on the three principal pollutants emitted by motor vehicles—hydrocarbons, carbon monoxide, and nitrogen oxides...
...Such a sweeping warning arises primarily from concern over air pollution's effects on acute and chronic respiratory disease...
...But it now appears that catalysts are converting this previously innocuous by-product into much more dangerous substances—sulfuric acid and highly toxic sulfates...
...In 1972, Dr...
...Babcock of course defends his own scale—faulting the others as either overweighting or underweighting different chemical reactions...
...The muddiness is by no means confined to automotive emissions or even air pollution more generally...
...Walther, Coordinator of Environmental Studies with the Museum of Northern Arizona, calculated that transportation sources accounted for 39.1% of all harmful air pollution effects, but Babcock and Nagda countered with the much smaller figure of 16.4...
...the scales vary considerably...
...An indication of the problem emerged during the furor over catalytic converters and the attending adjustments of interim automotive emission standards...
...As suggested above, the "knowledge gap" plaguing the pollution control inThe Alternative: An American Spectator February 1976 17 dustry is nowhere more palpable than in the spate of research attending the catalytic converter controversy...
...An EPA "Issue Paper," which was released on January 30, 1975, and which summarizes the results of a number of studies the agency commissioned on catalytic converters, states: "A detailed benefit-risk analysis was performed to estimate the trade-offs to public health in using oxidation catalysts by comparing increased sulfuric and exposure dis-benefits [sic] to benefits associated with reduced exposures to carbon monoxide and oxidants (unburned hydrocarbons are the key precursors...
...The "technical findings" and "scientific recommendations" which led to Train's announcement are truly comical...
...Confronted with these deadlines, American automobile manufacturers decided on one basic approach—the catalytic converter...
...There is a huge discrepancy between environmental rhetoric, which is deceptively clear, and known environmental fact...
Vol. 9 • February 1976 • No. 5
