"Peer review of peer review," is how EPA administrator Carol Browner describes the science underlying controversial new air quality standards for fine particulate matter and ozone. The EPA now says science demands changing allowable ozone concentrations from the current standard of 0. 12 parts per million over a one-hour average to 0.08 ppm over an eight-hour average, as well as adding new daily and annual standards for PM 2.5 microns in diameter or less (PM2.5).
The Science on ParticulatesBut the proposed standards failed public review. Flaws in the science on the PM 2.5 standard ran so deep that calls were made to release the underlying data from the key epidemiological studies on which the EPA relied: the Harvard Six Cities study and the Pope study. The studies' authors haven't allowed independent scientists to scrutinize their work-not surprising given the EPA's recent admission that it failed to catch a statistical error in the Pope study that forced the agency to lower the estimated benefits of the new fine particle standard from 20,000 to 15,000 reduced deaths annually. Questions about the studies forced the EPA to ask the Health Effects Institute to sponsor yet another review. HEI is slated to carry out a re-analysis of the key studies to determine their reliability.
This won't be finished for another two years. Nonetheless, the EPA is moving forward with the new PM 2.5 standard.
In June 1997, HEI met to discuss the form of the upcoming re-analyses. Comments at the meeting indicate that the key epidemiological studies may not support the new standards. Discussions centered around the usual problems with epidemiological studies-the difficulty of finding statistically significant associations between health and environmental factors, while ruling out other environmental influences, called confounding factors, as explanatory variables. These factors include smoking history, age, physical fitness, other pollutants, weather, social contact and allergen levels. Presenters at the meeting suggested any one of these variables may be responsible for the alleged association between PM and mortality.
In the Harvard study, some suggested that instead of fine particles, the age of the subjects studied was responsible for mortality; the subjects studied in cities with high pollution levels also tended to be older. Dr. Fred Lipfert of Brookhaven Laboratories showed that the levels of fine particles correlated with sedentary lifestyles-lifestyles low in exercise, high in alcohol and high in fat intake. In other words, the people who were supposedly dying early from exposure to fine particles might have actually died from unhealthy lifestyles. Confounding by lifestyle wasn't considered in the Harvard study. It isn't clear, however, whether a reanalysis of the data underlying these studies can resolve these issues. Some scientists suggested that new studies with higher quality data will have to be carried out instead. Such research will take years to complete. Nevertheless, the EPA continues to push for a new fine particle standard.
Dr. Kay Jones questioned the reliability of the Pope study at the HEI meeting. A re-analysis found the study's data plagued by inaccurate and incomplete air quality and mortality data. Most importantly, the re-analysis showed that the authors omitted data from several major cities without explanation. These cities included New Orleans, Pasadena, Calif, New York, Pittsburgh, St. Louis and San Antonio. Jones also found that the study's unreliable health history collection techniques resulted in counting smokers as nonsmokers, which misrepresented the risk associated with exposure to healthy individuals. According to Jones, all of these problems resulted in an inflated risk associated with fine particle exposure. In fact, he found that the estimated number of annual deaths from PM exposure in an American Cancer Society study was probably zero, rendering the EPA's estimate of 15,000 annual deaths from PM2.5 exposure invalid. In the case of the ACS study, peer-review appears to have failed.
The Science on OzoneUnlike the science on PM, the science on ozone is extensive and shows current ozone levels are safe. But the EPA claims that regions now in compliance with the current ozone standard still have unhealthy air, citing an ever-increasing number of young asthmatics as victims of lax standards. While it's true that asthmatics are the most sensitive to ozone levels and that an increasing number of people suffer from the ailment, there's no evidence that tightening the ozone standard will improve their situation.
The reason more kids have asthma probably isn't due to pollution. In fact, the asthma epidemic, which is sweeping western nations, is most pronounced in Australia and New Zealand, which, arguably, have the best air quality in the world. A recent New England Journal of Medicine article indicated air pollution was, in fact, neither causing nor exacerbating asthma in inner-city kids. That study found 50 percent of the children studied had high levels of cockroach antigen in their homes, while those children sensitive to cockroach allergen and exposed to high levels had 200 percent more hospitalizations from asthma. The study further concluded the increased asthma was likely due to kids spending too much time indoors where the air is significantly less healthy than the outdoor air the EPA wants to regulate further.
Overall, studies of ozone consistently show the healthy population isn't at risk from typical ozone exposures. Only those with highly compromised immune systems, such as severe asthmatics, may show effects from high levels of ozone. These health effects can appear at almost any level, but severe effects from ozone generally appear only in concentration levels far above the current standard of 0.12 ppm. One study found the 0.08 ppm proposed standard represented the lowest level at which effects were observable, but the health effects were experienced by normal subjects exposed constantly for seven hours-five spent exercising moderately. It isn't likely that most of us exercise outside for five hours on smoggy days. The problem of setting a standard to alleviate such types of effects is difficult, since such conditions are relatively rare. Unsurprisingly, the EPA's scientific advisory board, the Clean Air Scientific Advisory Committee had a difficult time figuring out where the ozone standard should be set, stating, "There is no 'bright line' [that] distinguishes any of the proposed standards as being sig nificantly more protective of public health."
CASAC also noted that some effects from ozone could be seen at any given level of exposure: "Based on information now available, it appears ozone may elicit a continuum of biological responses down to background concentrations ... The paradigm of selecting a standard at the lowest-observable-effects level and then providing an 'adequate margin of safety is no longer possible." In other words, no matter what standard the EPA proposes, there will be some health effects from urban smog, but tighter standards won't necessarily help. The question remains then, what type of health effects would be reduced under the tighter standard?
No AnswersDouglas Dockery, lead author of the Harvard study put it best when he stated at the HEI con ference that the studies of fine particles, "don't give us the answers." Until HEI and other groups conduct further research to determine what, if any, health effects stem from PM, regulation remains unjustified. As for the ozone standard, CASAC's opinion on the matter is clear: a tighter standard won't provide health benefits beyond the current standard. The costs of the new standards, however, are more certain. Both standards are estimated to place as many as 800 counties into nonattainment, and cost $150 billion annually. The health of the nation could be better served by allowing people and their state and local governments to keep their valuable resources for their own individual health care and education. As we all know, wealthier is healthier.
Late Breaking UpdateIn late July, EPA finalized the proposed air quality standards virtually as proposed. However, the standards are not effective immediately and will not be implemented for at least another six years. In the meantime, the Cambridge, Mass.-based Health Effects Institute has committed to review the scientific studies and data underlying the new standards. However, since HEI is 50 percent funded by EPA and 50 percent funded by the automobile industry, it isn't quite an "independent" review of the science. And the scientific data-collected at taxpayers' expense still hasn't been made available to the public.
Congress may yet get into the act. Under a new law enacted by the last Congress, it has 60 days to vote to overturn the new regulations. Any such vote would likely be vetoed by the President and it's likely that insufficient votes exist to override a presidential veto. Given the Republican Congress is gun shy on environmental issues (stemming from last year's public relations debacle with regulatory reform), it's quite possible that it won't even take a vote on the new standards for fear of being labeled "anti-environment." The irony is that it's not a Republican who's willing to lead the charge against the new standards, but a Democrat-Rep. John Dingell of Michigan.
Steve Milloy is executive director of The Advancement of Sound Science Coalition in Washington, D.C. Joel Bucher is with Citizens for a Sound Economy.
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