This article is the second in a three-part series by Joel Schwartz addressing the American Lung Association’s State of the Air 2007 report. Part I appeared in the July issue of Environment & Climate News.
In the July issue of Environment & Climate News I showed how the American Lung Association (ALA) misleads Americans about air pollution levels and trends in their communities and the nation. This month, I will document the evidence that even air pollution levels far higher than any we experience in the United States are perfectly safe, and that the nation’s air does not cause adverse health effects.
ALA claims, “Over 136 million Americans … are exposed to unhealthful levels of air pollution.” Even in terms of actual federal standards, this is a vast exaggeration. Fewer than 60 million Americans live in areas that violate either or both of the federal ozone and fine particulate (PM2.5) standards.
Of course, that would be 60 million people too many if their air were genuinely dangerous. But EPA has made the standards so stringent that exceeding them is no longer a cause for concern. Today’s ever-tighter air pollution standards are more about keeping the regulators and activists in power than protecting Americans from real risks.
Children’s Health Study
The Children’s Health Study (CHS), released May 2004, is one of the largest studies ever of the health effects of air pollution. Sponsored by the California Air Resources Board, CHS researchers tracked thousands of children in California from ages 10 to 18. The study found that higher levels of air pollution were associated with a lower risk of developing asthma.
For example, children who grew up in areas with the highest ozone levels in the nation were 30 percent less likely to develop asthma than children in low- or medium-ozone areas. Higher levels of particulate matter and nitrogen dioxide were also associated with lower asthma risk.
That’s not the only evidence that belies claims that air pollution causes asthma. Every air pollutant we measure has been dropping for decades, even as the prevalence of asthma has risen.
International data also show air pollution isn’t causing asthma. The prevalence of asthma is greatest in wealthy countries with low air pollution, while highly polluted developing and ex-Soviet Union countries have low asthma prevalence.
The former East Germany is Exhibit A. Before the fall of the Berlin Wall, eastern Germany had awful air pollution and low asthma. After reunification, eastern Germans adopted Western lifestyles. Air pollution dropped, and asthma rose to West German levels.
Ozone Not Causing Asthma
The Children’s Health Study came up with other surprising results. For example, the most polluted areas in the CHS exceeded the federal eight-hour ozone standard more than 100 days per year during the eight years of the study. But these relatively high ozone levels had no effect on children’s lung growth or capacity.
Growing up in an area with average PM2.5 levels twice as high as the federal standard was associated with only a 1 to 2 percent reduction in lung capacity. And even the most polluted areas of the country no longer come anywhere close to twice the federal standard.
Air pollution can exacerbate pre-existing respiratory conditions, but the effect is tiny at worst. Both federal and California regulators estimate that eliminating all human-caused ozone in the United States (somewhere around one-quarter to one-half of ozone is natural or transported from other countries) would prevent no more than 1 to 2 percent of all asthma emergency room visits and respiratory hospital admissions.
Contrary Evidence Ignored
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 higher ozone was associated with a decrease in serious health effects such as hospital admissions.
Both California and federal regulators omitted this result from their official estimates of harm from ozone, even though the California Air Resources Board sponsored the Kaiser study.
The pattern of asthma attacks also suggests ozone can’t be a significant factor in respiratory distress. Across the nation, emergency room visits and hospitalizations for asthma are lowest during July and August, when ozone levels are at their highest.
No Premature Deaths
The most serious claim leveled against air pollution is that it prematurely kills tens of thousands of Americans each year, even at today’s record-low levels. But here too, the real-world evidence says otherwise. Even air pollution at levels many times greater than Americans ever breathe doesn’t kill laboratory animals.
Researchers can’t, of course, do laboratory studies on people to see if air pollution kills them. But they can look for more mild health effects in human volunteers. Such studies provide little support for claims of serious harm.
Two major forms of PM2.5–sulfates and nitrates–are simply nontoxic. In fact, ammonium sulfate, the main form of particulate matter from coal-fired power plants, is used as an “inert control”–that is, a substance without any health effects–in human studies of harm from acidic particles. Inhaler medications to reduce airway constriction are delivered in the form of sulfate aerosols.
The lack of toxicity of power plant particulate matter is particularly ironic. In a slew of reports with scary titles like Death, Disease, and Dirty Power and Power to Kill, environmentalists have been running a vicious multi-year campaign against inexpensive coal-fired electricity, based on the false claim that power plant pollution is deadly.
Even Diesel Fumes Harmless
Even “carbonaceous” PM, 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.
Joel Schwartz ([email protected]) is a visiting fellow at the American Enterprise Institute.
For more information …
For more examples of exaggeration of harm from air pollution, see Joel Schwartz, Air Pollution and Health: Do Popular Portrayals Reflect the Scientific Evidence? http://www.joelschwartz.com/pdfs/AirPoll_Health_EPO_0506.pdf.