Initially, all clean air regions would be in Class II, where increases in emissions would be allowed if new sources used best available control technology. State Governors could then classify regions as Class III, where deterioration in air quality to the secondary NAAQS would be allowed, or as Class I, where only very limited increases in ambient concentrations would be allowed; the Federal government would also put some federal lands, such as national parks, into Class I. Regulations to this effect were promulgated in November 1974, and immediately came under attack from all sides. Environmentalists argued the Class III definition did not comply with the law, and not enough pollutants were included. Industry argued the whole scheme was an unwarranted usurption of power in the name of clean air. However, in the 1977 Amendments, Congress in large measure adopted the EPA approach, using the three-way classification concept and requiring "best available technology" to be used by any new source in an area where NAAQS were met as of 1977. AIR POLLUTION: TRENDS AND PROGNOSIS There were state air pollution control programs in place before the 1970 CAA superimposed its elaborate mechanisms and ambitious goals on them, and the environmental awakening of 1969-1970 would surely have stimulted these programs into greater effectiveness even without the 1970 CAA. Economic trends, notably the historical shift from coal to oil as the preferred energy source, were having an independent effect on air pollution at the same time. These influences, combined with the fact that systematic monitoring of pollution began only in this decade, make it extremely difficult to be very precise about the impact of the CAA itself on air pollution. Nonetheless, this subsection will review what evidence there is, and try to draw some conclusions concerning what the CAA has accomplished and is likely to accomplish. Air Pollutant Emission Trends Nationwide emissions of the "criteria" pollutants; i.e., those for which documents and NAAQS exist, increased more or less steadily from 1940 to 1970, although the trends slowed or reversed in the late 1960s. Since 1970, the annual total emissions data has indicated a fairly dramatic decline in (controllable) emissions of particulates, a slight decline for carbon monoxide, a barely perceptible decline for sulfur dioxide and hydrocarbons, and a slight increase for nitrogen oxides. The table below, in which an index of 100 is used for 1970 emissions, illustrates these trends. TABLE 2.-NATIONAL AIR POLLUTANT EMISSION TRENDS! 1 Data for years up to 1970 are from 1974 CEQ Annual Report, pp. 262-276, for 1970 and later from 1975 CEQ Annual Report, p. 306. Since these 2 data sets are compiled from slightly different sources, they do not agree perfectly on 1970 emissions, but the 1970 estimate from each source is used as 100 in the table here. One must, therefore, be cautious about comparing pre-1970 and post-1970 trends, especially for TSP. In trying to interpret these trends, one must keep in mind the great uncertainty in the estimates, which can easily cause a 10 percent fluctuation in the estimated emission level. For example, the 1974 estimate for sulfur dioxide is apparently calculated by "assessing" industry's "compliance status with SIP scheduled emission reductions," i.e., by guessing how well the legally specified emission factors were being met, while the particulate estimates include emissions from forest fires and dust storms." But, assuming the estimates are reasonably accurate, at least as to the trends they suggest, the following interpretation can be offered: 72 The 29 percent reduction in particulate emissions is due primarily to reductions in emissions from large coal-fired boilers and other industrial processes due to the substitution of oil for coal. This substantial reduction, which was well under way in 1970-71, suggests that the pre-1970 state programs were having some success in getting well-proven technology, clean fuels, and cleaner industrial practices applied. The 12 percent reduction in carbon monoxide emissions and the 6 percent reduction in hydrocarbon emissions are entirely attributable to reductions in motor vehicle emissions; these reductions. were due to federal and California mobile source standards set under the pre-1970 CAA. The 8 percent reduction in sulfur dioxide emissions is virtually all due to use of lower-sulfur fuel, with a small effect due to improved control of non-ferrous smelters; clean-fuel regulations are among the easiest of environmental regulations to formulate and enforce. The 10 percent increase in nitrogen oxide emissions is due to increases in automobile miles traveled (average emissions per mile remained essentially unchanged from 1970 to 1974), and in fuel combustion in stationary sources. In summary, the emissions data indicate that economic events and regulatory programs in place before the 1970 Amendments to the CAA were having an effect on emissions. It is too early to expect the effects of the regulatory innovations of the 1970 Amendments to show up in the data, although no doubt the existence of the 1970 CAA had a beneficial effect on the existing efforts even before its regulatory provisions became effective. Ambient Air Quality Trends Trends in ambient quality are even more difficult to establish than trends in total emissions, due to measurement and definitional problems. When some measures of ambient quality improve while others get worse, there is no agreed way to aggregate to establish "the" trend, and one must use several different measures and hope an overall picture emerges. When this is done for air quality, the conclusions are similar to those suggested by the national emissions data: a general trend toward improved air quality was evident before the 1970 CAA took effect; if anything, the trend has flattened out in more recent years. The most persuasive evidence to this effect comes from measurements of ambient particulate and sulfur dioxide levels at a fixed set "Particulate and Sulfur Oxide Emission Reductions * * *, 1970-1974." EPA, January 1976, p. 31. Based on data and hints in the EPA report, Ibid., and the 1975 CEQ Annual Report. of monitoring sites from 1970 to 1974. The figure below, from the 1975 CEQ Annual Report, illustrates the point. Average Levels of Total Suspended Particulates 1970 1971 1972 1973 1974 1970 1971 1972 1973 1974 1970 1971 1972 1973 1974 Another measure used to indicate trends in ambient quality is the percentage of monitoring stations reporting a violation of a NAAQS. This measure is suspect, however, since the number of stations has been growing since 1970, and hence the result will be biased if there is any tendency to locate new monitoring stations at cleaner or dirtier sites. For what it is worth, this measure indicates a more or less steady decrease in the percentage of stations reporting violations of suspended particulate and sulfur dioxide NAAQS. These ambient trends for particulates and sulfur dioxide are partly explainable in terms of the downward trend in emission levels. In addition, there has been a trend toward locating power plants and other large emission sources in rural areas, so that ambient levels in cities will show a larger decrease in ambient levels than the emission data would suggest, while rural areas will show less decrease or even an increase. To some extent, these pollutants are being spread more widely but at lower concentrations. Whether good or bad, this is a trend which was well under way before the 1970 CAA. For the automobile-related pollutants, the emission trends established by the pre-1970 programs carried over into ambient air quality trends in the 1970s. The frequency of violation of the carbon monoxide standard decreased slightly at urban sites, but remained high. Photochemical oxidants, formed in the atmosphere from the nitrogen oxides and hydrocarbons produced by automobiles and other sources, showed some slight tendency to drift downward near central cities. But persistent violations of the oxidant standard in rural areas is a newlyrecognized problem, caused by the movement of nitrogen oxides and hydrocarbons in air masses from urban to rural areas, where oxidants are formed." The Prognosis for Air Pollution Any prediction is hazardous, especially one about the future based on an imprecise picture of the present and recent past. But, on the basis of the preceding discssion of the implementation process, and some reasonable assumptions about the direction of future policy, economics and technology, the following observations can be made. Air Pollutant Emissions For stationary sources, further control is likely to come slowly, as energy-related variances are granted and the general trend toward relaxing pressure continues. Power plants are already controlling 94% of potential particulate emissions, are using fuel about as low in sulfur as they are likely to get, and are dragging out development and application of stack gas desulfurization. Iron and steel facilities, if the Jones and Laughlin "success story" is any indication, will show only slow and halting progress, and the prospect of making progress on those 130,000 smaller sources is not encouraging. Nitrogen oxides from fuel burning can only increase, unless energy conservation is dramatically successful for economic reasons. For mobile sources, the future is more uncertain, because an important technological development could change things quickly. There is little in the present policy to encourage that, however, so the best guess is that the trend in average emissions per mile will continue 13 "Monitoring and Air Quality Trends Report, 1974," EPA, February 1976. downward only slowly. Transportation control plans, which could save both gasoline and emissions, will remain unimportant. Ambient Air Quality and Effects As emissions of the criteria pollutants decline, ambient levels are likely to decline even more slowly. In some areas background levels of particulates or oxidants are near primary NAAQS, so that even total elimination of man-made emissions would leave relatively dirty air. And the dispersion of sources into rural areas is being discouraged. Such indicators as the fraction of monitoring stations reporting a violation of a standard may continue a downward trend, especially if new stations are continually added to the systems, and people may notice that things are a bit better than they used to be. But it is about as likely that measureable and noticeable improvement in air quality will slow down even further. 75 In addition, as ambient air quality improves-if it does-it may be discovered that many of the adverse effects do not decline proportionally. For example, it is generally accepted that the fine particulates pose the real health threat, and that these are not controlled as efficiently as total particulates by control devices; thus, even dramatic success at controlling particulates may leave the health threat undiminished. Similarly, sulfates are formed from sulfur dioxide in the atmosphere, in amounts which seem to be essentially independent of the sulfur dioxide concentration; if the health threat from sulfur is due to sulfates, as many suspect, then even high levels of sulfur dioxide control may not decrease the health threat.76 Heavy metal oxides. organic particulates, or nitrates may all contribute to the adverse effects attributed to air pollution, and may or may not be reduced along with other pollutants. And accomplishing the NAAQS, which is supposed to eliminate all adverse effects on health due to the criteria pollutants. is unlikely to do so; the "threshold theory" is not strong enough to make one confident that health effects will vanish when EPA declares the whole nation "in compliance." Thus, it is possible that the most significant air pollution problems would remain even if control of the criteria pollutants were more effective than it is likely to be. SUMMARY EVALUATION OF THE 1970 CAA The fact that the deadlines in the 1970 CAA have not been met does not mean that the Act has "failed." Even the rather pessimistic prognosis above does not demonstrate failure. In fact, that prognosis is meant to demonstrate that the problem of managing the nation's air resources is more complex, will be more costly, and will take longer to solve than the architects of the 1970 CAA anticipated. Perhaps no realistic management system could have accomplished more in terms of reducing emissions and improving ambient air quality than the 1970 CAA (and its predecessors) has done. Where the 1970 CAA can be judged a failure is in its principal regulatory innovations, and in its simpleminded view of what solution of the air quality management problem would require. The rigid deadlines have not done what they were supposed to do, and may have been 74 However, natural particulates may not be harmful to health in the same way manmade particulates are. 75 1974 CEO Annual Report, p. 266. 76 1975 CEQ Annual Report, pp. 327-333. |