The air pollution scare industry is at it again -- in a very timely manner to help the Environmental Protection Agency impose more dubious regulations on us.
“When the air is filled with increased levels of soot and other tiny particles, more people end up in the hospital with heart and lung problems, according to the largest study yet on the health effects of such pollutants,” reported the Chicago Sun-Times on March 8.
Published in the Journal of the American Medical Association, the study reports that “short-term exposure to [fine particulate air pollution or soot] increases the risk for hospital admission for cardiovascular and respiratory diseases.”
The researchers estimated that reducing average ambient soot levels by almost 75 percent would have reduced the total number of hospital admissions for a variety of heart and lung problems during 2002 in the 204 mostly urban counties studied from1,394,441 admissions down to 1,383,282 – a difference of 11,159 admissions or 0.8 percent.
Before we get to the question of whether the benefits of such a reduction would exceed the costs – let alone whether such a reduction is even possible -- we ought to examine the “air worthiness” of this estimate.
First, the researchers’ results are derived through purely statistical methods in which soot levels recorded by geographically-dispersed Environmental Protection Agency-operated air monitoring stations were matched with local hospital admissions records. Higher levels of soot were slightly correlated with increased hospital admissions, according to the researchers.
But there are several major drawbacks to the researchers’ methodology which, in the parlance of epidemiologists, is termed an “ecological study.”
First, no one knows how much soot any of the hospitalized patients were exposed to. The researchers simply assumed that people are exposed to the level of soot measured by the closest EPA monitoring stations, a distance of 5.9 miles from their residences on average. But the likelihood of varying environmental conditions over such distances and time spent indoors-versus-outdoors raises significant doubts about the validity of their assumption.
Next, not a single patient’s hospitalization was diagnosed by an attending physician as being due to air pollution. The researchers simply assumed that, for a specified level of soot, any “extra” hospital admissions were due to soot.
Since the population studied consisted entirely of elderly Medicare patients and since there is no biological explanation for how short-term exposure to low-levels of soot could possibly cause acute heart and lung problems, its quite likely that the hospitalizations had nothing whatsoever to do with soot.
The researchers know very well that ecological studies, at best, may be useful for designing future studies, but are not capable of proving cause-and-effect relationships. Study author Jonathan Samet of the Johns Hopkins University once even discouraged the use of ecological studies, stating in the context of indoor radon, “The methodologic limitations inherent in the ecologic method may substantially bias ecologic estimates of risk...”
So why claim such a certain connection between soot and health when the data and study method are so deficient?
As it turns out, the study was funded by the U.S. Environmental Protection Agency, which conveniently just started a rulemaking process in January that would make outdoor air quality standards more stringent.
The study was released on March 7, in time for the March 8 newspapers – the same day that the EPA held a public hearing in Chicago on the need for new air pollution standards.
The need for more stringent air pollution regulation is certainly open to debate, if for no other reason than that current EPA air pollution rules were issued in 1997 and have not yet been fully implemented – much less, evaluated in terms of benefits and costs.
The EPA claims that hundreds of studies show that current air quality levels harm the public’s health. But virtually all of these studies, however, have been funded by the EPA -- an agency once famously accused by its own Science Advisory Board of “adjusting science to fit policy” – conducted by the same clique of EPA-funding-dependent researchers, and suffer from the exact same weaknesses as the study published this week.
You would think that if the case was so clear-cut concerning current air quality and public health, it would take only a few good studies to sufficiently make the link. Instead, we’re barraged with hundreds of studies that prove nothing except that, if there is some risk to health from current levels of air pollution and public health, it is exceedingly small and difficult to detect.
Technology exists to significantly improve studies on air pollution and health. Study author Francesca Dominci told me that personal monitors exist that could more precisely indicate what levels of air pollution people actually experience. But, she said, that would cost millions of dollars.
Given that national compliance with the last round of EPA air quality rules costs an estimated $10 billion annually, it make sense for the agency to spend a few million dollars to improve the exposure data on which such costly regulation is based – but don’t hold your breath waiting for that to happen.