Our air is cleaner than it’s been in a century, writes Joel Schwartz. So why do Americans worry it’s so dirty and dangerous?
Americans are driving more miles, using more energy, and producing more goods and services than ever. But at the same time, the air quality in America’s cities is better than it has been in more than a century—despite the fact that the U.S. population has almost quadrupled and real GDP has risen by a factor of nearly thirty.
But Americans aren’t aware of this good news—or don’t believe it. Polls show the public thinks that air pollution has been steady or even rising over the last few decades, that it will worsen in the future, and that it is still a serious threat to people’s health. They are convinced that pollution is a serious problem throughout the country, that it is a major cause of asthma and other respiratory diseases, and that it shortens the lives of tens of thousands of people.
Much of what Americans think they know about air pollution is false. Through exaggeration and sometimes even outright fabrication, the main purveyors of the story—journalists, government regulators, environmentalists, and even health scientists—have created public fear out of all proportion to the actual risks.
Air pollution has been declining for decades across the United States. The chart below tells the story. Between 1980 and 2005, average levels of air pollution fell between 20 percent and 96 percent, depending on the pollutant. For example, sulfur dioxide, which results mainly from the burning of coal and the smelting of some metals, is down 63 percent, while carbon monoxide, the vast majority of which comes from automobiles, is down 74 percent. At the same time, coal usage increased more than 60 percent and miles of driving nearly doubled.
Virtually the entire nation now meets federal standards for sulfur dioxide, carbon monoxide, nitrogen dioxide, and lead. The country is also near full compliance for the U.S. Environmental Protection Agency’s older standards for ozone (the “one-hour” standard) and particulate matter (the “PM10” standard for airborne particulate matter less than ten micrometers in diameter).
Compliance has also greatly improved for the more stringent ozone and PM standards the EPA adopted in 1997. In 1980, about 75 percent of the nation’s ozone monitors violated the eight-hour ozone standard, but the rate was down to 18 percent at the end of 2005. About 90 percent of the nation violated the fine particulate matter (PM2.5, or airborne PM under 2.5 micrometers in diameter) standard in 1980, but the proportion had dropped to 16 percent by the end of 2005.
Air pollution will continue to decline. The EPA tightened automobile emission standards in 1994, 2001, and 2004. The last of those rules requires reductions that will cut automobile emissions (including those from SUVs and pickups) by 90 percent below the emissions of the current average car. Even after accounting for expected increases in total miles of driving, the net effect will be a reduction of more than 80 percent in total automobile pollution emissions over the next couple of decades. Emissions from on- and off-road heavy-duty diesel vehicles will follow a similar trajectory as 90 percent reduction requirements come into effect for these vehicles in 2007 and 2010, respectively. Industrial emissions will also continue to fall under the EPA’s Clean Air Interstate Rule, which will eliminate most remaining power plant pollution.
Despite the nation’s spectacular progress, polls show that most Americans think air pollution has stayed the same or even increased, and will worsen in the future. Typical is a 2004 poll by the Foundation for Clean Air Progress, which found that only 29 percent of respondents believed that “America’s air quality is better than…it was in 1970.” Some 38 percent said it was worse, and 31 percent said it was about the same. In fact, by any measurement, air quality is enormously improved.
Nevertheless, it’s hardly surprising that Americans are pessimistic about air pollution, since much of the information they receive is at odds with reality. Here are a few examples of the distortions:
- In November 2001, the Sierra Club reported, “Smog is out of control in almost all of our major cities.” Those words were published just after the nation had achieved two record-low years in a row for both ozone and PM2.5. In 2002, near the end of a fourth consecutive record-low year for PM2.5, the Public Interest Research Group published “Darkening Skies,” which claimed PM2.5 was increasing. Although the number of days exceeding the eight-hour ozone standard declined more than 70 percent between 1973 and 2003, The Washington Post nevertheless lamented early in 2004 that “ozone pollution has declined slightly over the past 30 years” (emphasis added). Despite large reductions in automobile emissions during the last few decades, a 2003 USA Today article claimed Americans now drive “vehicles that give off more pollution than the cars they drove in the ’80s.”
- In December 2005, the EPA proposed lowering the allowable daily PM2.5 concentration from 65 micrograms per cubic meter (g/m3) down to 35 g/m3. The change, which the EPA recently made final, will increase by two-thirds the number of metropolitan areas that fail to comply with federal particulate standards. Yet activists and journalists have created the impression that the EPA has not tightened the standards at all. “EPA proposes ‘Status Quo’ revisions to [particulate matter standards],” claimed an American Lung Association press release. According to Clean Air Watch, another environmental group, “President Bush gives early Christmas present to smokestack industries.” The Atlanta Journal-Constitution’s headline read, “EPA Barely Budges on Soot; Health Advice Disregarded.” The tougher PM2.5 standard represents a major expansion of the reach and stringency of the Clean Air Act, but environmentalists and many journalists passed it off as no change at all.
- The years 2003 through 2005 were the three lowest on record for ozone. Over this short period, the proportion of the nation’s ozone monitors violating the EPA’s eight-hour standard plummeted from 43 percent to 18 percent. Instead of celebrating, shortly after the 2005 ozone season ended, a Clean Air Watch press release proclaimed, “Smog Problems Nearly Double in 2005.” Pennsylvania’s Department of Environmental Protection warned, “Number of Ozone Action Days Up from Last Year.” Ozone levels were indeed higher in 2005 when compared with 2004, but the alarmist headlines were extremely misleading. In fact, 2005 was the second-lowest on record for ozone since the 1970s, and 2004 was the lowest. Ozone levels were so improbably low in 2004 that it would have been astounding if ozone had not been higher in 2005. What was remarkable was that 2005 was one of the hottest years on record, and warmth increases ozone formation. But ozone levels still remained near the all-time low. Opinion makers turned this success into an apparent failure.
The lack of context adds to misperceptions about pollution. Clearly, some place in the United States has to be the worst at any given time. But even in the worst areas of the country, air pollution is much lower now than it used to be. Riverside, California, has the highest PM2.5 levels in the country, but PM2.5 in Riverside has dropped by more than half since the early 1980s, even as the area’s population has more than doubled. Ignoring and obscuring these large improvements add to the gap between public perception and actual air quality.
The most serious claim leveled against air pollution is that even at current levels it kills tens of thousands of Americans each year. The EPA credits federal pollution regulation with preventing hundreds of thousands of premature deaths during the last 35 years, and, as a result, believes the Clean Air Act has delivered tens of trillions of dollars in benefits. But the existence of these benefits depends on whether the comparatively low air pollution of the last few decades is deadly. Controlled human and animal studies suggest that it is not.
Even air pollution at levels many times greater than Americans ever breathe doesn’t kill laboratory animals. As a recent article in the journal Regulatory Toxicology and Pharmacology concluded, “It remains the case that no form of ambient [particulate matter]—other than viruses, bacteria, and biochemical antigens—has been shown, experimentally or clinically, to cause disease or death at concentrations remotely close to U.S. ambient levels.”
Researchers cannot, of course, do laboratory studies on people to see if air pollution will kill them. But they can look for milder health effects in human volunteers. Such studies also provide little support for claims of serious harm.
Two major forms of particulate matter—sulfates and nitrates—are simply nontoxic. In fact, ammonium sulfate, the main form of particulate matter from coal-fired power plant emissions, is used as an “inert control”—that is, a substance without any health effects—in human studies of the effects of acidic aerosols. Inhaler medications to reduce airway constriction are delivered in the form of sulfate aerosols. Nevertheless, in a glut of reports with scary titles like “Death, Disease, and Dirty Power” and “Power to Kill,” environmentalists have been running an aggressive campaign against coal-fired electricity, claiming that tens of thousands of deaths are caused by power plant particulates.
Even “carbonaceous” particulate matter—the noxious, sooty emissions from diesel trucks and other motor vehicles—causes surprisingly little reaction, at least at concentrations encountered in urban air. Studies sponsored by the Health Effects Institute had healthy and asthmatic volunteers ride an exercise bike while breathing concentrated PM2.5 collected in the Los Angeles area, or concentrated diesel exhaust. In both cases, the exposures were many times greater than typical levels in urban air, and even a few times greater than peak levels in the most polluted cities. Nevertheless, there were no changes in symptoms or lung function in either the healthy or asthmatic subjects.
Controlled laboratory evidence, therefore, indicates that low-level air pollution doesn’t cause premature death. The claim that tens of thousands of Americans die each year from even the relatively clean air in modern American cities instead rests on indirect evidence from so-called “observational” epidemiology studies, in which researchers look for correlations between air pollution and risk of death in large groups of people.
Observational studies work with subjects who are not randomly selected and with pollution exposures that are not randomly assigned. Researchers use statistical methods to try to remove the biases inherent in the resulting data. Most epidemiological studies you read about in the newspaper—studies that assess the effects of diet or health habits on the risk of cancer or heart disease, for example—are of this nonrandomized, observational variety.
Most health claims based on such observational studies are turning out to be false when tested in large, randomized clinical trials—a “gold standard” methodology that avoids the biases of observational methods and is the type of study required for drug approvals. Spurious health claims from observational studies have become such a pervasive concern in the medical literature that health researchers have been creating new journals specifically designed to combat the problem.
Perhaps not surprisingly, regulators, environmentalists, and most air pollution epidemiologists have ignored these weaknesses and continue to assume that observational studies provide valid information about air pollution’s health effects. They point to the thousands of observational studies that have reported a positive association between low-level air pollution and risk of death as proof that the harm is real. But implementing an invalid methodology over and over again doesn’t improve its validity.
Of course, air quality regulation isn’t just about preventing death, but also about mitigating lesser, but still serious, health concerns. The entire corpus of air pollution health claims, however, rests on surprisingly thin evidence. Asthma is the most conspicuous example. According to the Centers for Disease Control, the prevalence of asthma nearly doubled in the U.S. during the last 25 years. Environmentalists have made asthma sufferers the literal poster children for air pollution activism, parading them before regulatory agency hearings and creating the impression that air pollution is a major culprit. The Carolinas Clean Air Coalition’s website goes so far as to claim that “1⁄3-1⁄2 of all asthma in North Carolina is due to air pollution.”
But how can air pollution be the cause of rising asthma if asthma prevalence rose at the same time that air pollution of all kinds sharply declined? Also, asthma is most common in wealthy Western countries that have relatively low air pollution levels, while developing countries with awful air pollution have comparatively little asthma.
Environmentalists and regulators also create the impression that air pollution accounts for a large proportion of all respiratory distress. According to an EPA fact sheet, “Ozone can irritate lung airways and cause inflammation much like a sunburn…. People with respiratory problems are most vulnerable, but even healthy people that are active outdoors can be affected when ozone levels are high.” “Digging Up Trouble,” a recent report by the Union of Concerned Scientists on diesel construction equipment in California, claims that “as much as 10 to 20 percent of all summertime hospital visits and admissions for respiratory illness are associated with ozone.”
But regulators’ own technical studies belie these exaggerations. Researchers from both the EPA and the California Air Resources Board, or CARB, have published technical reports suggesting that eliminating all human-caused ozone (somewhere around one-quarter to one-half of ozone is natural or transported from other countries) in the United States—a much larger reduction than required to comply with the current eight-hour ozone standard—would prevent no more than 1 or 2 percent of all asthma emergency room visits and respiratory hospital admissions.
Even these small benefits are inflated, because they omit contrary evidence. For example, researchers from Kaiser Permanente studied the relationship between air pollution and respiratory distress in California’s Central Valley, and reported that higher ozone was associated with a statistically significant decrease in serious health effects, such as hospital admissions. Although it was the sponsor of the Kaiser research, CARB omitted this result from its study of the benefits of ozone reductions.
The pattern of asthma attacks also indicates that ozone can’t be a significant factor in exacerbating such respiratory diseases. Emergency room visits and hospitalizations for asthma are lowest during July and August, when ozone levels are at their highest.
What about the long-term effects of pollution on respiratory health? Key evidence comes from CARB’s Children’s Health Study (CHS), long-term research begun in 1993. After following more than 1,700 children from ages 10 to 18, University of Southern California scientists published a study in The New England Journal of Medicine using CHS data that found no association between ozone and lung growth or capacity—despite the fact that some of the communities in the study exceeded the federal eight-hour ozone standard more than 100 days per year.
The same report also suggests that particulate matter, even at the highest U.S. levels, causes little developmental harm. Long-term exposure to PM2.5 at twice the level of the federal standard was associated with only a 1 to 2 percent decline in children’s lung capacity.
The researchers’ press release on the study created a false appearance of serious risk. Titled “Smog May Cause Lifelong Lung Deficits,” the release asserted, “By age 18, the lungs of many children who grow up in smoggy areas are underdeveloped and will likely never recover.” This is what newspapers reported, rather than what the study actually found. It is just one of many cases in which health experts have created an appearance of much greater harm than justified by the underlying evidence.
The most recent results from the CHS, published in The Lancet, the respected British medical journal, last January, concluded that even growing up near a major freeway was associated with only about a 1 percent decline in total lung capacity. That finding was based on pollution levels during the 1990s, when measurements showed that automobile and diesel truck emissions were two to four times greater than now. Nevertheless, in a familiar pattern, the researchers claimed they had uncovered serious harm, and this is what newspapers uncritically reported.
Still, if air pollution is not the threat most Americans think it is, don’t we have the Clean Air Act and aggressive regulatory authorities to thank? Not really.
Regulators and environmentalists have created the impression that air pollution was on an ever-rising trajectory before the federal government stepped in to protect Americans from unrestrained capitalism. In reality, air pollution had been dropping for decades before the 1970 adoption of the modern Clean Air Act.
Pittsburgh reduced particulate levels by more than 75 percent between the early 1900s and 1970. Chicago, Cincinnati, and New York all have records going back to the 1930s or 1940s showing large reductions in smoke levels. Nationwide monitoring data demonstrate that particulate levels declined nearly 20 percent between 1960 and 1970, while sulfur dioxide declined more than 30 percent. Los Angeles began reducing ozone smog in the 1950s, soon after skyrocketing population and driving created this new form of air pollution. Ozone levels in Los Angeles have been dropping ever since.
Air pollution is not unique in this respect. For decades before the federal government got involved, a range of environmental concerns was being mitigated by a combination of ad hoc local and state regulation, nuisance lawsuits, and market forces that pushed for better efficiency and technology. Other dangers were declining as well. Per mile of driving, the risk of dying in a car accident dropped 75 percent between 1925 and 1966, the year Congress created the National Highway Traffic Safety Administration. The risk of dying on the job declined 55 percent between 1930 and 1971, the inaugural year of the Occupational Safety and Health Administration. And for all of these risks, the rate of improvement was about the same before and after the federal government stepped in.
After several decades living under what legal scholar David Schoenbrod calls the “modern administrative state,” it may seem unimaginable that public goods like cleaner air or safer cars could be delivered without the command and control of powerful national regulators. Unfortunately, we didn’t merely trade a decentralized system for an equivalent centralized one. Instead, federal air quality regulation has added a great deal of collateral damage into the bargain.
A good example is a policy called New Source Review (NSR), which requires businesses to install state-of-the-art pollution controls when they build a new plant or upgrade an existing one. Routine repair and maintenance are exempt, allowing existing older plants to keep operating without cleaning up their emissions. The idea was that emissions would decrease over time as existing facilities reached the end of their natural useful lives and were replaced by clean modern plants.
It didn’t work out that way. By increasing the costs of new and upgraded plants relative to existing ones, NSR encouraged businesses to keep old plants running as long as possible—ironically slowing progress on air quality. And NSR is just one among many requirements with perverse outcomes.
By the mid- to late-1990s, regulatory economists estimated that the Clean Air Act was costing Americans on the order of 1 to 2 percent of GDP per year—about $1,000 to $2,000 per household. The incremental costs of attaining the tougher ozone and PM2.5 standards that the EPA has adopted since then will likely add an additional $1,000 or so a year to the average household’s outlay, but will provide little or no incremental health benefit in return.
The EPA’s war on pollution marches on, nevertheless. The agency recently adopted a new PM2.5 standard, and plans to propose a tougher ozone standard in June that will represent a vast expansion of the Clean Air Act’s reach. About 23 percent of the nation’s metropolitan areas violate the current standard. This fraction would double even under the EPA’s least stringent alternative. Under the most stringent alternative, literally the entire nation would become a Clean Air Act “nonattainment” area.
Federal air quality regulation suffers from incentives to create requirements that are unnecessarily stringent, intrusive, bureaucratic, and costly. The Clean Air Act charges the EPA with setting air pollution health standards. But this means that federal regulators decide when their own jobs are finished. Not surprisingly, no matter how clean the air, the EPA continues to find unacceptable risks. The EPA is like a company that gets to decide how much of its product customers must buy. Congress also charges the agency with evaluating the costs and benefits of its own programs. Not surprisingly, the EPA finds the benefits to be far in excess of the costs.
But the conflicts of interest go much deeper. The EPA and state regulators’ powers and budgets depend on a continued public perception that there is a serious problem to solve, yet regulators are also major funders of the health research intended to demonstrate the need for more regulation. Regulators decide what questions are asked, which scientists are funded to answer them, and how the results are portrayed. Regulators also provide millions of dollars a year to environmental groups, which use the money to augment fear of pollution and seek increases in regulators’ powers.
Before the EPA was created, decentralized actions were delivering the improved air quality that an increasingly wealthy and educated polity was demanding. Before the era of compulsively detailed regulation, the government’s role was, to paraphrase economist Sam Peltzman, complementary to market forces, evolving gradually and incrementally, and largely working in concert with people’s values and preferences.
By contrast, today’s federal regulatory system imposes revolutionary institutional changes that often override people’s preferences and suppress individual initiative and creativity. Schoenbrod, a law professor and a senior fellow at the Cato Institute, began his career as an idealistic attorney for the Natural Resources Defense Council during the 1970s. But his experiences convinced him that the modern administrative state is unkind to the people it claims to be protecting. Regulators, he says, have “left the public more anxious about pollution than ever. Such anxiety fuels the growing power of the administrative state.”
The prospects for improving air quality regulation are not encouraging. Even the Bush administration has aided alarmism rather than reform. Environmentalists and many newspaper editorial boards have relentlessly pilloried the president for supposedly “gutting” the Clean Air Act and increasing air pollution. Meanwhile, back in the real world, air pollution continues to hit new record lows; the Bush EPA has imposed the nation’s toughest-ever air pollution standards and regulations, going far beyond where the Clinton administration chose to tread; and, perhaps most ironic, the Bush administration has justified this vast expansion of the Clean Air Act based on the same spurious health claims through which environmentalists and regulators maintain unwarranted public anxiety.
Realistic public information on air quality is a prerequisite for popular support for a sensible regulatory system focused on results and net improvements in Americans’ welfare. Unfortunately, the media have so far shown little interest in improving environmental reporting. True, many journalists realize that environmentalists are often prone to exaggeration and that the regulatory system suffers from significant structural problems. But they also seem to believe regulators and environmentalists are well-intentioned, while the critics of regulation must have nefarious motives. Alas, speculation about motives is a poor basis for judging the value of public policies or regulatory institutions. As C. S. Lewis wrote, “Of all tyrannies, a tyranny sincerely exercised for the good of its victims may be the most oppressive.… [T]hose who torment us for our own good will torment us without end for they do so with the approval of their own conscience.”
Joel Schwartz was formerly executive officer of the California agency charged with evaluating the state’s vehicle emissions inspection program. He is a visiting fellow at the American Enterprise Institute and author of the book “No Way Back: Why Air Pollution Will Continue to Decline.”
Steven F. Hayward and Amy Kaleita, 2007 Index of Leading Environmental Indicators, AEI and Pacific Research Institute, 2007.
John Ioannidis, “Why Most Published Research Findings Are False,” PLoS Medicine, vol. 2 (2005), pp. 696-701.
Sam Peltzman, “Regulation and the Natural Progress of Opulence,” AEI-Brookings Joint Center for Regulatory Studies, 2004.
David Schoenbrod, Saving Our Environment from Washington: How Congress Grabs Power, Shirks Responsibility, and Shortchanges the People (New Haven: Yale University Press, 2005).
David Schoenbrod, “Putting the ‘Law’ Back into Environmental Law,” Regulation, Spring 1999.
Joel Schwartz, “Air Pollution and Health: Do Popular Portrayals Reflect the Scientific Evidence,” Environmental Policy Outlook, no. 2, 2006.
Joel Schwartz, “Air Quality: Much Worse on Paper than in Reality,” Environmental Policy Outlook, May-June 2005.
Joel Schwartz, “Air Pollution: Why Is Public Perception So Different from Reality?” Environmental Progress, vol. 25, no. 4 (2006), pp. 291-297.
Joel Schwartz, No Way Back: Why Air Pollution Will Continue to Decline (Washington, D.C.: AEI Press, 2003).