Finding Better Ways to Achieve Cleaner Air

Available in Adobe Acrobat PDF format

Though air quality continues to improve, those gains have come at the cost of a regulatory system that also devotes enormous resources to creating and enforcing administrative requirements, rather than reducing pollution. The National Research Council recently issued a report evaluating U.S. air quality management and recommending reforms. Unfortunately, the report focuses on symptoms and fails to address fundamental problems with air quality law and regulation. The public's interest is in sufficiently clean air achieved at the least possible cost. But getting to this ideal will require overcoming special interests that benefit from a centralized, administratively complex regulatory system.

Air quality has improved dramatically across the United States during the last few decades, and existing requirements will eliminate most remaining air pollution emissions during the next twenty years or so.[1] Unfortunately, in addition to substantial pollution reductions, the Clean Air Act (CAA) and its associated Environmental Protection Agency (EPA) regulations and guidance have created a compulsively detailed administrative system that places process and centralized power ahead of results and devotes great resources toward small, expensive, slow, and ineffective pollution reduction measures, while ignoring opportunities for large, cheap, and rapid improvements. We can do better than this: we can have cleaner air, we can have it sooner, and we can pay less for it, in terms not only of direct costs, but also in terms of lost economic growth and limits on our citizens' freedoms.

A National Research Council (NRC) panel recently issued a report highlighting some of the problems with the current U.S. air quality management system and put its considerable gravitas behind recommendations for reform.[2] Unfortunately, despite good intentions, the NRC's report focuses mainly on symptoms and does not attempt a diagnosis or solution of underlying problems. The report also frequently suffers from vague, factually incorrect, or contradictory conclusions, often stated without supporting analysis.

The NRC does not address the forces that have shaped the current system and resisted change, including interest groups that benefit from centralized control and administrative complexity. Instead, the NRC treats perceived deficiencies in air quality regulation as if they were technical problems that could be solved with better information and analysis, more funding, or more collaborative effort on the part of participants in the regulatory system. Its recommendations therefore address some of the undesirable results of the current system, without addressing how to mitigate the underlying systemic factors that have caused those undesirable results.

This essay evaluates the major features of U.S. air quality policy in the context of the NRC's analysis and suggests systemic reforms that would focus air quality regulation on results instead of process and administration.

A Process-Focused System

There is no question that the country has had great success in reducing air pollution. Sixty percent of monitoring locations violated the one-hour ozone standard in the late 1970s, but only 10 percent still violate the standard today.[3] For "fine" particulate matter (PM2.5)[4], the violation rate went from about 80 percent down to 18 percent. Nearly 97 percent of monitoring sites now attain standards for "coarse" particulate matter (PM10), and virtually the entire nation attains standards for carbon monoxide, sulfur dioxide, nitrogen dioxide, and lead. Average PM2.5 levels have declined 40 percent since the late 1970s, while the average number of one-hour ozone exceedances per year has dropped nearly 95 percent.[5] Yet the fact that pollution has declined since the 1970 passage of the CAA tells us nothing about whether our current air-quality management system was an especially good way to get there or is now a good way to manage future air-quality policy. A wide range of evidence suggests that dramatic improvements are possible.

In principle, if the federal government wanted states to achieve given air-pollution levels, it could simply have dictated to states (1) the standards and the dates by which those levels would have to be achieved, (2) how attainment would be measured, and (3) the penalties for failure. Given sufficiently large penalties, states would have an incentive to find effective means of meeting their obligations. Such a Clean Air Act could be written on a few pages and would require few or no EPA regulations.

Instead, the Clean Air Act is hundreds of pages long, and EPA has written thousands of pages of regulations to implement the CAA requirements, along with tens of thousands of pages of guidance documents to explain what the regulations mean. States must develop their own laws and regulations to implement the federal requirements, and businesses must obtain permits that often specify operating conditions and pollution control methods unit by unit and process by process, and that must be amended any time a production process is changed. Legions of lawyers and consultants help businesses figure out what the rules mean and how to comply with them. The vast majority of this activity has nothing to do with reducing air pollution, but instead involves creating and then demonstrating compliance with administrative requirements. Indeed, just a few emissions requirements--mainly for motor vehicles and power plants--are responsible for the vast majority of air pollution reductions achieved since the Clean Air Act was passed.[6]

One window into the process-focused nature of air regulation is the State Implementation Plan (SIP) process--the centerpiece of the CAA, through which states demonstrate to EPA how they plan to reduce pollution and ultimately attain federal standards. A SIP includes an inventory of the estimated pollution emissions from all sources in a region, a series of pollution control measures that the region commits to implement to reduce pollution, and an "attainment demonstration"--a combination of computer modeling and other analysis that purports to demonstrate that the region will attain federal pollution standards once the SIP control measures are fully implemented. Once approved by EPA, the control measures and other commitments in the SIP become legally enforceable.

Despite the ostensible goal of improving air quality, in reality it is far more important to have an EPA-approved SIP than to actually reduce air pollution or attain federal air standards. Failing to do the former can result in costly sanctions such as withholding of federal highway funds and limits on economic development, while failing in the latter results in an extension of the attainment deadline and the requirement that a new SIP be submitted.

SIPs are huge, complex documents that virtually defy comprehension or analysis. Many SIPs run to thousands of pages, and more than a thousand state and federal regulators around the country spend most or all of their time creating, maintaining, amending, and reviewing SIPs, while probably thousands more at regulated businesses and activist groups closely follow and attempt to influence SIP provisions.

The SIP planning process and the regulations that flow from it take place within a world that is almost hermetically sealed off from reality.

For example, the emissions inventories used in SIPs have been known since at least the late 1980s to be inaccurate and have repeatedly failed real-world validation tests.[7] One key problem is that field studies indicate that gasoline vehicles contribute anywhere from 50 to 75 percent of human-caused volatile organic compound (VOC) emissions in U.S. metropolitan areas, but official inventories typically have only about 40 percent of VOC coming from gasoline vehicles.[8] Nevertheless, these official emissions inventories, hundreds of tons per day for a typical metropolitan area, yet reported source-by-source with tenth-of-a-ton-per-day precision, are treated as real in the regulatory process and continue to misdirect multi-billion-dollar pollution control and transportation infrastructure decisions.

Starting from this bogus emissions inventory, EPA then prospectively awards emission reduction "credit" for control measures in a given SIP based on assumptions about how effective the control measures will be. A state's goal is then to garner enough SIP credit to make a paper attainment demonstration. The inaccuracy of the inventory guarantees that SIP credit determinations will be phony, but the situation is much worse than that. EPA even awards SIP credit for programs that are known to be ineffective.

For example, EPA awards substantial SIP credit for vehicle emissions inspection and maintenance (I/M) programs, despite a well-documented history of their real-world ineffectiveness.[9] At the same time, EPA does not award any SIP credit for other potential methods of reducing emissions from high-polluting cars, such as using an inexpensive technology called remote sensing to find high polluters as they drive on the road and then requiring that they be repaired or scrapped. In fact, EPA considers it double counting to award SIP credit for on-road remote sensing, because that credit has already been awarded for I/M programs. Since states can receive SIP credit only for traditional scheduled I/M programs, that is what they implement. This is fine with state regulators, since EPA began requiring I/M programs in many areas during the 1980s, and the state bureaucracies that have grown up around these programs have an interest in their continuation. The perverse result is that even as on-road measurements continue to find many high-polluting cars on the road, regulators implicitly make believe they do not exist, since they have been dealt with--on paper, that is--by I/M.

Because states receive SIP credit up front, they have little incentive to perform a valid evaluation of the real-world effectiveness of their programs, and EPA has not required rigorous evaluations. There is no upside to such an effort, but there is a tremendous potential downside for both state and federal regulators, because a negative evaluation could result in the loss of both the SIP credit necessary to keep the highway funds flowing and the political legitimacy of air pollution control programs. There is also no incentive to seek alternative strategies that would clean the air in the real world, because EPA has decreed up front what "works" for the purposes of meeting CAA process requirements.

The federal regulatory system is not only unnecessarily complex and wasteful, evidence suggests federalization of air pollution control was also unnecessary. Air quality had been improving for decades before passage of the Clean Air Act due to a combination of common law nuisance torts, local and state regulation, and market pressures toward greater energy efficiency and technological advancement.[10] Furthermore, although one pretext for federalization was interstate transport of air pollution, EPA focused its efforts on intrastate pollution and created regulatory incentives that actually worsened interstate pollution transport by encouraging power plants and other industrial plants to build tall smokestacks that sent pollution elsewhere rather than eliminating it.[11]

Interstate pollution is not the only case of regulatory outcomes coming out just the opposite of what one might expect from a system supposedly focused on pollution reduction. For example, the New Source Review (NSR) program requires businesses to install state-of-the-art pollution controls when they build a new plant or make major modifications to an existing one. NSR thus makes new or upgraded facilities relatively more expensive than existing ones and therefore predictably encouraged businesses to put their research and development efforts into keeping old plants running well beyond their nominal useful lives.[12]

How did air pollution regulation get this way? A number of analysts have shown that a complex, centrally controlled, bureaucratic, and process-focused Clean Air Act serves the interests of environmental activists, federal and state regulators, and even many regulated businesses.[13] Environmental activists gain power, prestige, public relations opportunities, and even increased funding in a centralized, complex, and coercive regulatory system with many administrative decision points. The huge administrative burdens created by the Clean Air Act ensure a continued need for large numbers of state and federal regulators and give those regulators great power over Americans' lives.

For businesses, appropriately structured command-and-control regulations can provide direct financial benefits, limit competition, or harm competitors. Examples include the gasoline oxygenate requirement, which directly funnels money from motorists to the ethanol industry and corn agribusinesses; New Source Review, which limits competition by putting new businesses at a competitive disadvantage; and the 1977 CAA amendments' requirement that electric utilities install scrubbers, which protected the high-sulfur eastern coal industry from competition from low-sulfur western coal. Ironically, these measures, though passed under the guise of environmental protection, were actually on balance harmful to air quality.

These politically powerful groups benefit from the current system and resist changes to the status quo.

For example, flexible and less expensive regulations, such as tradable permits, are rarely supported by these groups. In a tradable permit system, the key political decision--how much to reduce pollution--is made up front and covers a wide range of facilities. From then on such programs are "largely self-executing and self-enforcing, resting on decentralized, market-based, decision-making processes."[14] Market-based programs thus reduce the power of and need for professional environmental activists and regulators and make their accumulated expertise in the current system obsolete. Market-based programs also reduce the opportunity to confer regulatory largesse on favored businesses or industries.

Treating the Symptoms, Misdiagnosing the Problems

The NRC understands the nature of the SIP process, noting, for example, that it "focuses primarily on compliance with intermediate process steps," "probably discourages innovation and experimentation at the state and local levels," and "draws attention and resources away from the more germane issue of ensuring progress toward the goal of meeting [federal air pollution standards]." Moreover, the NRC realizes that the Clean Air Act places meeting SIP process requirements above actual air quality improvements.[15]

Unfortunately, the NRC uses invalid metrics for evaluating how well the SIP process works. The first metric is to look at improvements in ambient air quality, for which the NRC concludes "the SIP process has resulted in considerable progress in improving air quality on the basis of this metric." The second is to determine "whether implementation of federal, regional, and local programs through the SIP process has resulted in the attainment of [federal standards] for criteria pollutants." Based on this metric, the NRC finds that the effectiveness of the SIP process is "less apparent."[16]

Yet both of these metrics are irrelevant for determining the value of the SIP process. Pollution might have gone down faster and further, and the reductions might have been cheaper with a different system. Indeed, air pollution had been declining for decades before 1970 when EPA was created and the Clean Air Act federalized air pollution control. Conclusions about the SIP process can only be drawn based on an assessment of the specific nature and performance of that process relative to some normative standard and to other potential options.

Despite criticizing the SIP process for failing to focus on results, the NRC also concludes that "the SIP process is an important and essential component of the nation's [air quality management] system" and "has resulted in considerable progress in improving air quality."[17] Thus, rather than junking the SIP process, the NRC recommends improving it to make it more dynamic and performance oriented. Yet because the NRC's criteria for assessing cause and effect are fundamentally invalid, the NRC's report does not provide evidence to support any particular conclusions or recommendations on the SIP process.

Be that as it may, the NRC's plea to reform the SIP process to focus on results is not likely to get very far, because it does not address the underlying reasons for the failings of the current system. For example, the NRC recommends a greater focus on real-world performance of air quality programs, including institution of a system to continually review air quality progress to make sure that pollution improvements are meeting expectations in the SIP, followed by as-needed adjustments if progress falls below expectations, and greater collaboration in this effort among relevant federal and state agencies. But the failure of participants in the SIP process to focus on performance instead of procedures is not a matter of poor management or technical incapacity, but is rather an inherent structural feature of the system and of the interests of its participants.

The NRC is also aware of the inaccuracy of the emission inventories used to develop SIPs and recommends improvements in emissions tracking and estimation, for example, "improvement in current and projected mobile-source emission inventories through expansion of the in-use emission measurement program for on-road vehicles," "independent efforts, using ambient as well as emissions data, to validate and improve models," and "incorporation of more formal uncertainty analysis, based on the validation efforts, in the presentation and use of inventories."[18]

Once again, these recommendations would be all well and good if the problem were merely one of getting better information into regulators' hands. But the problems with emissions inventories have been public knowledge since at least the late 1980s. EPA has since gone through three revisions of its computer model for predicting vehicle emissions (the model is called MOBILE, and the latest version is MOBILE6), and real-world validation tests continue to reveal considerable discrepancies between the model and real-world data.[19] Not only is the model wrong on overall vehicle emissions, it is wrong in detail. For example, the model overpredicts the emissions of new cars relative to old cars, meaning that SIPs, which must be prepared using MOBILE6, are overestimating future vehicle emissions and therefore underestimating future emission reductions from turnover of the vehicle fleet.[20] Future emissions will thus be lower in reality than they are in the model. But since the model is what drives policy, regulators will have to implement additional pollution control measures to offset these future phantom emissions. As a result, the SIP process may force the nation to waste perhaps billions of dollars "solving" a non-problem, even as regulators ignore current real sources of pollution that are observed in practice but are missing from regulators' emission inventories.

The fundamental problems in air quality management are structural and political, rather than technical or scientific. The official emissions inventories used by regulators never have come close to reflecting the technical state of the art. Rather, various factors related to custom, standard operating procedures, and political economy have militated against using realistic inventories. At the same time, the air quality regulatory system is structurally insulated from having to base plans and regulations on realistic estimates of emissions or of the effectiveness of emissions-control measures.

While it criticizes some process-focused features of air regulation, the NRC actually lauds the Title V permitting program created by the CAA amendments of 1990, noting that "Title V permits can play an important role in limiting emissions."[21] As with the SIP process, the NRC provides no evidence to support this vague claim. Yet there is much evidence to support the contrary conclusion that permitting is more about power, funding, and control than about air quality improvement, and that complex permit processes and requirements are a symptom of the process-focused nature of the Clean Air Act, rather than a good way to reduce air pollution.

Before Title V, facilities had to comply with emissions limitations regardless of whether they had a permit. However, more detailed and complex permits do confer benefits on regulators. Speaking of the requirements imposed by the permitting system, law professor David Schoenbrod concludes, "No major facility can hope to avoid violating such an exacting system of legally binding requirements. . . . More than a few former colleagues of mine at the Natural Resources Defense Council, who now work for corporations trying to comply with environmental law, tell me . . . their clients can't help but violate the law, no matter how hard they try, because the legal requirements are just too complex and confusing. . . . The point of this compulsive system is power, not environmental quality."[22]

Schoenbrod also points out that Title V is really a disguised mandate to tax, because it requires businesses to pay a permit fee that EPA deems sufficient to fund not only the issuance of permits, but the bulk of state air-pollution control programs. Thus, "unelected federal officials now supplant the budgetary and taxing authority of elected state officials. The State and Territorial Air Pollution Program Administrators Association and the Association of Local Air Pollution Control Officials vigorously supported the federal mandate for permits and federal mandates in general. After all, the federally mandated permit fee amounts to a 'Full Employment for Air Pollution Officials Act.'"[23] As with other aspects of Clean Air Act process requirements, the NRC has a tin ear for the political economy of Title V, and instead lauds the permit fees because they "have provided a useful source of income to agencies that allows them to develop a more effective permit program."[24]

The NRC itself unintentionally makes the case that Title V merely represents more administrative burden rather than real air-pollution improvement, and the council's analysis is worth quoting at length:

The EPA inspector general issued a report in 2002 that examined the reasons for delays in the issuance of [Title V] permits. These reasons included delays in the promulgation of the initial EPA regulations for state and local Title V permit programs, delays in the EPA approval of proposed permit programs, and longer times required for review and approval of permits. . . . The delay in issuing guidance for specific monitoring requirements in the Title V regulations was also cited as a reason for the delay in the implementation of the Title V program. The complexity of the effort required to issue these permits was underestimated at the time the 1990 CAA Amendments were passed. . . . An example of a complex permit is one granted to an oil production company in California. This Title V permit . . . contains 1,460 pages to describe the conditions applied to all the permit units in the source.[25]

And this is just the issuing of the permits. Once that happens, companies have to comply with each and every permit requirement and regulators have to check to make sure that they do so. Permits must be amended each time a piece of equipment or process is changed. All of this rigmarole is unrelated to air pollution reductions, but it does support large numbers of jobs at regulatory agencies and the environmental compliance departments of regulated businesses.

Turning to New Source Review, the NRC concluded that although NSR has "resulted in reduced emissions from [major new stationary sources]," it has also "provide[d] an incentive for industries to extend the life of higher-emission (grandfathered) facilities."[26] Once again the NRC suffers from a lack of systemic thinking. Of course NSR ensures that any new facilities that get built will have state-of-the-art pollution controls, since that is a requirement for getting a new facility approved. But that has nothing to do with whether NSR has reduced emissions overall, since there is no way to keep the emission limitations required by NSR for new facilities without also keeping all of NSR's undesirable emissions-increasing side effects. These side effects are inherent in a regulatory system that makes new and upgraded facilities relatively more expensive than preexisting ones. A more relevant question is whether NSR has reduced industrial air pollution to a greater extent and more cost effectively than would other potential policies, such as a declining overall emissions cap on groups of industrial facilities with no differential treatment based on facility age. But this question remains unasked in the NRC report.

It might seem unfair to criticize the NRC for failing to come to terms with the political, legal, economic, and social aspects of the air pollution regulatory system. After all, the NRC is a scientific body, and its charge was to address "scientific and technical aspects of the policies and programs that are intended to manage important air pollutants . . . regulatory standards development, air quality management plan development, plan implementation, and progress evaluation"[27] (emphasis added). Yet the NRC clearly realized that the process-oriented nature of air pollution regulation is an important shortcoming, felt empowered to pass judgment on key Clean Air Act legal and regulatory structures such as SIPs and permits, and made recommendations intended to focus the regulatory system more on results. The NRC panel included economists, lawyers, and regulators, also reflecting the perceived need for the panel to be able to address more than just purely scientific and technical issues. Indeed, if the NRC had interpreted its charge literally, it would have guaranteed a useless report, because the key issues in air quality regulation are not fundamentally scientific or technical, but political and economic. Unfortunately, the NRC misdiagnoses the nature and shortcomings of air quality regulatory programs and makes recommendations that at best address only the symptoms of the Clean Air Act's underlying maladies.

Even on relatively pure science questions, the NRC makes some surprising blunders. A key example is ozone control strategy. Ozone is formed from volatile organic compounds (VOC) and nitrogen oxides (NOx). However, scientists have known since at least the 1980s that when the ratio of VOC to NOx is sufficiently low, reducing NOx actually increases ozone. This appears to be the situation in many cities, as evidenced by the so-called weekend effect, in which NOx drops 10 percent to 40 percent on weekends (because of reductions in diesel truck traffic) relative to weekdays, but ozone rises.[28] Despite the evidence, the NRC report asserts categorically that NOx controls are the appropriate strategy for reducing ozone and that VOC controls are ineffective. The NRC report does not mention the weekend effect or its implications and does not refer to any of the peer-reviewed research on ozone-control strategy cited here in note twenty-eight. This evidence suggests that EPA's recent strategy of pursuing large NOx reductions could backfire and make ozone worse in many cities. At the very least, the NRC report does not reflect the weight of the evidence and the uncertainties regarding ozone-control strategies, and therefore provides misleading analysis and recommendations on one of the most important emerging policy debates in air pollution control.

Toward Real Reform

In retrospect, law professor and former Natural Resources Defense Council litigator David Schoenbrod has little good to say about the regulatory system he helped create. "The best estimates are that we could have achieved the present level of environmental quality at a quarter of the direct cost . . . the current regime of pollution control also creates immense indirect costs by imposing paper work requirements and by discouraging new plants and innovations. . . . [W]e are not just hurt in our pocketbooks but in our ability to live our lives in ways that are most fulfilling to us. . . .[W]e launched regulatory systems that work along quasi-military lines and that unnecessarily curb freedom."[29]

The public's interest is in sufficiently clean air achieved at the lowest possible cost, not only in terms of the direct costs of air pollution control, but also indirect economic and social costs imposed by large command-and-control bureaucracies. The NRC does not raise the issue this starkly and does not even come close to addressing how to make federal air pollution regulation move toward this goal.

What might such a system look like? Schoenbrod has suggested the key features of an admittedly radically reformed air pollution regulatory system: First, the federal government would return air pollution regulation to the states, except for those few cases, such as interstate air pollution, that state governments do not have appropriate incentives or ability to address. Before the 1970 Clean Air Act amendments, state and local governments and the courts were actively and effectively addressing air pollution problems as they were understood at that time.[30] This recommendation would require air pollution policy to be made by legislators closer to the people affected by the laws they enact.

Second, legislation at any level of government would be based on proscribing unjust conduct, such as excessive pollution, rather than on abstract ideals such as to "protect public health with an adequate margin of safety," as the Clean Air Act requires. This would effectively mean that neither Congress nor any other legislative body could delegate legislative authority to an administrative agency like EPA. "With legislators having to take responsibility for the hard choices and deprived of the political profit that comes from unfunded mandates, from blame shifting through delegation, and from case work, legislators would lose their stake in growing the power of the state.[31]

Finally, the judicial process would look more like the common law. For example, rather than giving third parties standing to sue, real injury would be required for standing. Remedies would, where possible, emphasize compensation for or injunctions against harm, rather than the criminal and civil penalties imposed for violating administrative requirements endemic to the permit-based, command-and-control system.

Implementing these recommendations would create an air pollution regulatory system more likely to tailor pollution controls that are proportionate to the problem, that are focused on results rather than administrative process, that deal with real risks and harms rather than abstract ideals, that take account of the overall effects of proposed solutions on constituents, and that are just.

Of course, this is all pie in the sky. The interest groups that benefit from it will continue to vigorously defend and promote the centralized, administratively complex command-and-control system under the guise of environmental and public-health ideals. The vast majority of the public is unaware of the costs of the current system, providing little impetus for change. Worse yet, despite vast improvements in air quality during the last few decades, the public is more worried than ever about the risks of air pollution "because the idealistic approach [inherent in the Clean Air Act] puts EPA in the business of getting the public to worry about the 'failure' to attain unattainable ideals. The agency and others who get power and money from pollution control are far more ready to identify problems and to propose increases in their power than to say that things are reasonably safe."[32]

Even within the current Clean Air Act legal and regulatory structure, relatively modest reforms could make air pollution regulation much more effective and less expensive. For example, using state-of-the-science emission inventories as the starting point for SIP development, reducing emissions through declining caps, rather than source-by-source prescriptive regulations, and basing SIP credit on demonstrated real-world reductions would go a long way toward reducing at least the direct costs of pollution control. But the fact that even these modest reforms, which have been floating around in policy circles for many years, have not yet been implemented indicates the sclerosis of the current system.

As for the NRC's report, EPA has convened an advisory committee to assess how to implement the NRC's recommendations. The committee expects to complete its work by the end of the year. No doubt this will result in another report and a suggested process for incorporating its findings into EPA policies. What could be more fitting?


1. Joel Schwartz, No Way Back: Why Air Pollution Will Continue to Decline, (Washington, D.C.: The AEI Press, 2003), available at /files/2004/09/01/files/2004/09/01/20030804_4.pdf. See also Joel Schwartz and Steven F. Hayward, "Air Quality in America: A Dose of Reality on Air Pollution Levels, Trends, and Health Risks," American Enterprise Institute presentation, April 28, 2004, available at /files/2004/09/01/files/2004/09/01/200404301_schwartzhayward.pdf.

2. National Research Council, Air Quality Management in the United States (Washington, D.C., 2004).

3. To attain the one-hour ozone standard, a region must have no more than four days in any consecutive three-year period in which the average ozone level during any one-hour period reaches or exceeds 0.125 parts per million (ppm), hence the name of the standard.

4. This refers to airborne particles up to 2.5 microns in diameter. PM10 includes particles up to 10 microns in diameter.

5. Schwartz and Hayward, "Air Quality in America."

6. This is so, among other reasons, because these sources accounted for most of the pollution to begin with.

7. Robert F. Sawyer, Robert A. Harley, et al., "Mobile Sources Critical Review: 1998 NARSTO Assessment," Atmospheric Environment 34 (2000): 2161-2181; Armistead Russell and Robin Dennis, "NARSTO Critical Review of Photochemical Models and Modeling," Atmospheric Environment 34 (2000): 2283-2324; National Research Council, Modeling Mobile-Source Emissions (Washington, D.C., 2000) and references therein.

8. John G. Watson, Judith C. Chow, and Eric M. Fujita, "Review of Volatile Organic Compound Source Apportionment by Chemical Mass Balance," Atmospheric Environment 32 (2001): 1567-1584.

9. National Research Council, Evaluating Vehicle Inspection and Maintenance Programs (Washington, D.C., 2001) and references therein.

10. Indur M. Goklany, Clearing the Air: The Real Story of the War on Air Pollution (Washington, D.C.: Cato Institute, 1999).

11. David Schoenbrod, Time for the Federal Environmental Aristocracy to Give up Power (St. Louis: Center for the Study of American Business, 1998); and David Schoenbrod, "Why States, Not EPA, Should Set Pollution Standards" in Environmental Federalism, Terry L. Anderson and Peter J. Hill, eds. (Lanham, MD: Rowman & Littlefield, 1997).

12. Steven F. Hayward, "Making Sense of 'New Source Review'," Environmental Policy Outlook (July-August 2003, AEI), available at

13. Terry L. Anderson, ed. Political Environmentalism: Going Behind the Green Curtain. (Stanford, CA: Hoover, 2000). See also Roger E. Meiners and Andrew P. Morriss, eds. The Common Law and the Environment: Rethinking the Statutory Basis for Modern Environmental Law (Lanham, MD: Rowman & Littlefield, 2000).

14. Todd J. Zywicki, "Industry and Environmental Lobbyists: Enemies or Allies?" in The Common Law and the Environment: Rethinking the Statutory Basis for Modern Environmental Law, Roger E. Meiners and Andrew P. Morriss, eds. (Lanham, MD: Rowman & Littlefield, 2000).

15. National Research Council, Air Quality Management, 128.

16. Ibid., 126.

17. Ibid.

18. Ibid., 286.

19. Alison K. Pollack, Chris Lindhjem, et al., "Evaluation of the U.S. EPA Highway Vehicle Emission Factor Model," (Atlanta: Coordinating Research Council, 2004), available at

20. Peter McClintock. "MOBILE6 vs. On-Road Exhaust Emissions and MOBILE6 Evaporative Credits vs. I/M Gas Cap Failures," 19th Annual Mobile Sources Clean Air Conference (Steamboat Springs, CO: 2003).

21. National Research Council, Air Quality Management, 161.

22. David Schoenbrod, "Protecting the Environment in the Spirit of the Common Law" in The Common Law and the Environment: Rethinking the Statutory Basis for Modern Environmental Law, Roger E. Meiners and Andrew P. Morriss, eds. (Lanham, MD: Rowman & Littlefield, 2000).

23. Ibid.

24. National Research Council, Air Quality Management, 191.

25. Ibid.

26. Ibid., 215.

27. Ibid., 363.

28. For more on the "weekend effect, see Joel Schwartz and Steven F. Hayward, "Emissions Down, Smog Up. Say What?" Environmental Policy Outlook (January-February 2004, AEI), available at; Douglas R. Lawson, "The Weekend Effect--the Weekly Ambient Emissions Control Experiment," Environmental Manager (June 2003), 17-25. See also Eric M. Fujita, William R. Stockwell, et al., "Evolution of the Magnitude and Spatial Extent of the Weekend Ozone Effect in California's South Coast Air Basin 1981-2000," Journal of the Air & Waste Management Association 53 [7] (2003): 864-875; Betty K. Pun and Christian Seigneur, "Day-of-Week Behavior of Atmospheric Ozone in Three U.S. Cities," Journal of the Air & Waste Management Association 53 [7] (2003): 789-801; Linsey C. Marr and Robert A. Harley, "Spectral Analysis of Weekday-Weekend Differences in Ambient Ozone, Nitrogen Oxide, and Non-Methane Hydrocarbon Time Series in California," Atmospheric Environment 36 (2002): 2327-2335; Steven D. Reynolds, Charles L. Blanchard, and Stephen D. Ziman, "Understanding The Effectiveness of Precursor Reductions in Lowering 8-Hr Ozone Concentrations--Part II. The Eastern United States," Journal of the Air and Waste Management Association (forthcoming).

29. Schoenbrod, "Protecting the Environment in the Spirit of Common Law."

30. Goklany, Clearing the Air.

31. Schoenbrod, "Protecting the Environment in the Spirit of Common Law."

32. Ibid.

Joel Schwartz is a visiting fellow at AEI and the author of No Way Back: Why Air Pollution Will Continue to Decline (AEI Press, 2003).

Also Visit
AEIdeas Blog The American Magazine

What's new on AEI

AEI Election Watch 2014: What will happen and why it matters
image A nation divided by marriage
image Teaching reform
image Socialist party pushing $20 minimum wage defends $13-an-hour job listing
AEI on Facebook
Events Calendar
  • 20
  • 21
  • 22
  • 23
  • 24
Monday, October 20, 2014 | 2:00 p.m. – 3:30 p.m.
Warfare beneath the waves: The undersea domain in Asia

We welcome you to join us for a panel discussion of the undersea military competition occurring in Asia and what it means for the United States and its allies.

Tuesday, October 21, 2014 | 8:30 a.m. – 10:00 a.m.
AEI Election Watch 2014: What will happen and why it matters

AEI’s Election Watch is back! Please join us for two sessions of the longest-running election program in Washington, DC. 

Wednesday, October 22, 2014 | 1:00 p.m. – 2:30 p.m.
What now for the Common Core?

We welcome you to join us at AEI for a discussion of what’s next for the Common Core.

Thursday, October 23, 2014 | 10:00 a.m. – 11:00 a.m.
Brazil’s presidential election: Real challenges, real choices

Please join AEI for a discussion examining each candidate’s platform and prospects for victory and the impact that a possible shift toward free-market policies in Brazil might have on South America as a whole.

Event Registration is Closed
No events scheduled this day.
No events scheduled this day.
No events scheduled this day.
No events scheduled this day.