Clearing the air

Published December 1, 2000

In recent years a spirited debate has been conducted in law journals over the reasons why the national government took over environmental regulation in the 1970s. The general issue is whether or not state governments were embarked on a “race to the bottom,” deliberately sacrificing environmental quality, especially air quality, to snare more businesses and jobs.

The debate is based largely upon theoretical arguments and economic models of firms’ decisions to locate new factories under different states’ environmental standards. Law journal articles by Richard Revesz, John Dwyer, and Peter Swire are typical of this debate.

As a scientist and engineer trained to base my arguments on data, I tend to avoid law review articles because of the authors’ dogged disregard for empirical data. These articles on the history of air pollution fit the model.

They make virtually no reference to empirical data on air quality or emissions estimates. Without such data, any conclusion logically arrived at is valid so long as it does not contravene any laws of nature. The writer is constrained only by his or her imagination in dreaming up “what-ifs.”

Empirical data, however, will narrow any debate to the more likely premises and outcomes. Empirical data on air pollution can, in fact, resolve this “race to the bottom” debate.

Because I had worked on air pollution for both the State of Michigan and the Chicago regional office of the Environmental Protection Agency, the characterization of state agencies as indifferent to citizens’ desires for cleaner air struck me as oversimplified, if not false.

Accordingly, several years ago I began a systematic compilation of air pollution data and trends going back as far as possible to determine whether they support the states’ alleged ineffectiveness in curbing air pollution. Out of this effort came a book, Clearing the Air: The Real Story of the War on Air Pollution, that attempts to “clear the air” by bringing empirical data to bear on the veracity of these claims.

What the data show

Three kinds of historical data tell the story: indoor air quality, outdoor air quality, and estimated emissions of pollutants per national output.

Indoor air quality data were derived from 1940 through 1990 using, as a crude proxy, residential combustion emissions per occupied household, data I had compiled from the EPA and Bureau of the Census in a 1996 article for Ambio.

Outdoor air quality trends were developed by collecting, for each pollutant, data from EPA (or predecessor agencies’) reports on air quality trends, Council on Environmental Quality’s annual reports (Environmental Quality), and the Statistical Abstracts of the United States. The early trends are based on data from 60 cities for particulate matter (PM) and 21 urban areas for SO2. These are the best data available, and they indicate that matters were improving in urban areas which, by and large, had the worst air pollution.

Finally, the national emission estimates came from EPA’s emissions trends reports, which provide data from 1900 onward for SO2, VOC, and NOx, and from 1940 for PM and CO.

Indoor air quality. In the United States, we forget that indoor air quality, particularly in the home, is a far better indicator of the impact of air pollution on public health than is outdoor air quality.

According to EPA’s 1989 Report to Congress on Indoor Air Quality, 70 percent of the average person’s time is spent indoors at home; another 23 percent of the time is spent indoors elsewhere. Worldwide, the World Health Organization estimates, 3 million people are killed each year by air pollution: 2.8 million of them, mainly in developing countries, by indoor air pollution from the burning of coal, wood, and dung inside the home.

Early in the twentieth century, the situation was not much better in the United States, where people used to cook and heat their homes with coal or wood. But as households became more prosperous, they began to invest in new technology such as gas, oil, and even electricity for heating and cooking.

Between 1940 and 1990, indoor air quality, according to EPA’s own emissions estimates, improved by over 90 percent for particulate matter (PM, a measure of soot and smoke), carbon monoxide (CO), and sulfur dioxide (SO2). More than 90 percent of these improvements occurred before 1970, i.e., before federalization.

Outdoor air quality. Outdoor air quality also improved remarkably rapidly before 1970, most notably for particulates and sulfur dioxide. These are the pollutants associated in the popular mind with the deaths attributed–rightly or wrongly–to the air pollution episodes of Donora, Pennsylvania in 1948 and London in 1952.

Particulate levels, which had been in decline at least since the 1940s, fell an additional 15 percent between 1957 and 1970. Sulfur dioxide declined 40 percent between 1962 and 1969. Similarly, smog—a problem first and foremost in the Los Angeles area—had been improving there since the 1950s.

Emissions data. Emissions of pollutants, when estimated per unit of national output, show a similar dramatic decline. For sulfur dioxide, emissions per unit of GNP peaked in the 1920s. For volatile organic compounds and nitrogen oxides, the two major contributors to smog, the peak occurred in the 1930s. For particulates and carbon monoxide, the peak was in the 1940s or earlier.

As I reported in 1999, at least 70 percent of the reductions between these peaks and the 1997 levels occurred before the national government took over environmental regulation. The first improvements came voluntarily when more prosperous households, businesses, and industries started switching to cleaner fuels and adopting more efficient technologies.

These data refute the claims of a theoretical race to the bottom, as well as claims that the air was getting worse in the period preceding national control. Furthermore, national regulatory control does not seem to have accelerated substantially (if at all) the declines in emissions or improvements in air quality for the most important pollutants.

Even so, some still argue for federal control on the grounds that pollution can have interstate impacts. But 30 years of experience show that federal control does not guarantee successful or, for that matter, efficient solutions to interstate problems such as acid rain.

Racing to the top

The rise and fall of air pollution during the twentieth century tracks well with the premise that people continually strive to improve their quality of life.

In the early stages of economic development, society focuses on becoming wealthier so that it can better afford basic services such as sewage treatment, water supply, electricity, and hospitals. During this period, the environment suffers. Thus, initially the “race to the top of the quality of life” may look like a “race to the bottom” of environmental quality.

After a certain point, improving society’s quality of life means devoting more resources to solving environmental problems. Thus, environmental degradation is first arrested and then reversed; society goes through an “environmental transition.” After the transition, greater wealth and technology improve rather than worsen environmental quality, and the race to the top of the quality of life mirrors a “race to the top” of environmental quality.

There are several implications of these findings. Now that the United States is past its environmental transition, we are not likely to see any rollback of air quality if regulatory power is devolved to state governments.

Moreover, the easy—and many of the harder—air pollution problems have already been solved. To ensure that further improvements in environmental quality and the quality of life go hand in hand, environmental requirements should be fine-tuned to each state’s special circumstances, something impossible with one-size-fits-all federal regulations.

The historical experience suggests that the federal government should enter into a partnership with states, and the current command-and-control, pollutant-by-pollutant approach should be replaced with one that would minimize overall risks to public health and welfare. Emissions trading should be broadened to allow trading across pollutants. Trading should encourage not just emission reductions, but reductions in risks to health and welfare.

The federal government can set idealized goals, but the states should determine their own schedules and control measures to attain those goals. This is appropriate since they will be the major winners or losers from their own actions (or inaction). Thus, downwind states should be free to accept alternative risk reductions if that would provide greater benefits. A state might prefer funding to provide some health insurance for its indigent, rather than additional scrubbers upwind to reduce sulfur dioxide.

Optimizing the quality of life should be left to each state’s political process. To echo Winston Churchill’s statement about democracy, it may be the worst method—until you consider all the others.

Indur M. Goklany is a Julian Simon Fellow at PERC. He is on leave from the U.S. Department of the Interior. His work as an independent scholar at PERC is not part of his official duties with Interior and does not necessarily reflect views or policies of that or any other branch of the federal government.


Dwyer, John P. 1995. The Practice of Federalism Under the Clean Air Act. Maryland Law Review 54: 1183-1225.

Environmental Protection Agency. 1989. Report to Congress on Indoor Air Quality, Vol. 2: Assessment and Control of Air Pollution. EPA/400/1-89/001C. Washington, DC: Environmental Protection Agency, Office of Air and Radiation.

Goklany, Indur M. 1996. Factors Affecting Environmental Impacts: The Effects of Technology on Long-Term Trends in Cropland, Air Pollution, and Water-Related Diseases. Ambio 25: 497-503.

———. 1999. Clearing the Air: The Real Story of the War on Air Pollution. Washington, DC: Cato Institute.

Revesz, Richard L. 1992. Rehabilitating Interstate Competition: Rethinking the ‘Race to the Bottom’ Rationale for Federal Environmental Regulation. New York University Law Review 67 (December): 1210-1254.

Swire, Peter P. 1996. The Race to Laxity and the Race to Undesirability: Explaining Failures in Competition among Jurisdictions in Environmental Law. Yale Law Policy Review, Yale Journal on Regulation, Symposium Issue: Constructing a New Federalism: Jurisdictional Competence and Competition 14 (2): 67-110.

World Health Organization. 1997. Health and Environment in Sustainable Development. Fact Sheet 170. Geneva: World Health Organization.