epa's air standards pushing too far, too fast?

n e w s f o c u s

Pushing too far, too fast? The road to new ozone and particulate matter air quality standards is paved with good intentions, ambiguous science

Linda Ross Raber C&EN Washington

F lowers are blooming, birds are sing­ing, lovers walk hand-in-hand. But there's more than just spring in the

air. And it's enough to make you sick— or is it?

Over the past 27 years, the U.S. has spent more than $450 billion to clean the air of life-threatening pollution. By any­one's measure, this effort has achieved tremendous success, but problems re­main. The most recent report card issued by the Environmental Protection Agency indicates that pollution levels have been reduced nearly 30%, on average, over this period with even greater gains made for some of the most serious pollutants-such as lead and carbon monoxide—and in some of the most polluted cities.

Despite those achievements, EPA has proposed new regulations that suggest the U.S. has a long way to go. Last No­vember, EPA Administrator Carol M. Browner proposed new, tighter, national ambient air quality standards for ground-level ozone and particulate matter. EPA coupled the two proposals because ozone and particulate matter come from similar sources and cause similar prob­lems; however, Browner is under court order to come to a decision on the par­ticulate matter standard by July 19.

Since November, an enormous public relations effort has turned up the heat on EPA, on the Clinton Administration, and on Congress to stop the agency from moving forward with the new regula­tions. A smaller effort, waged with fewer dollars and a fraction of the lobbying power, has supported EPA's moves and is pushing for standards even tighter than those Browner is proposing.

At issue is a fundamental policy ques­tion of whom do you protect from what

and at what cost. EPA and supporters of the proposed standards point to children suffering miserably with asthma, unable to play outside in the summer, depen­dent on medications. It's easy to under­stand that from the viewpoint of an­guished parents in a hospital emergency room, no cost is too high to protect their chUd.

Others, including most U.S. industry, say as costs go up—and these standards would cost a fortune—they have to lay off employees. They ask "Are children better served by having unemployed parents?" Numerous studies much less ambiguous than the ones cited by EPA to back its pro­posals show that the one condition that is clearly and consistency related to child­hood asthma is poverty. How, then, should Browner play Solomon?

The Clean Air Act directs her as EPA's administrator to set air quality standards at levels that, in her judgment, protect the public health with an adequate mar­gin of safety. That is the law and that is her job. According to the Clean Air Act, Browner must base her decision on pub­lic health considerations alone. She must not consider the cost of implementing standards. And she must use the best available science to guide her decision.

To inform the administrator's deci­sion, the law requires EPA to convene the Clean Air Scientific Advisory Commit­tee (CASAC). This independent scientific review committee includes at least one member of the National Academy of Sci­ences, one physician, and one person representing state air pollution control

This article is available on the World Wide Web at http://pubs.acs.org. Click on "What's New" or "Hot Articles."

Browner: under court order to decide

agencies, along with a number of other specialists. It is charged with examining the current science on criteria pollutants and advising the administrator on wheth­er the standards should be revised.

Given the precise wording of the Clean Air Act, the inexact nature of epi­demiology, and the paucity of some air quality information, Browner may be doomed to lose what she sees as a battle for children's lives.

Those for and against EPA's proposals are marshaling the large body of scientific information on the health effects of ozone and particulate matter to reinforce their positions. Opponents of the new stan­dards have latched onto the shortcomings in the science and are exploiting every dif­ference of opinion among CASAC mem­bers. Advocates of these standards, includ­ing EPA, point to the huge number of studies that implicate the pollutants in children's health problems.

Part of the reason that these proposed standards have been so problematic lies in the Clean Air Act itself. The national ambient air quality standards have been a cornerstone of the Clean Air Act since 1970. The law requires EPA to set stan-

1 0 APRIL 14, 1997 C&EN

Chafee: reason to be worried

dards to reduce ozone, particles 10 urn or less in diameter, lead, carbon monox­ide, nitrogen dioxide, and sulfur dioxide to levels that are more than adequate to protect public health. But EPA can no longer follow the letter of the law, be­cause science, as it has evolved, does not provide clear answers about the thresh­olds of danger.

Since it is impossible to find a zero-risk level, it follows that it's also impossible to tack on a margin of safety. So any decision that is made to regulate criteria pollutants under the Clean Air Act is ultimately a pol­icy call for the EPA administrator.

And Browner believes that the weight of scientific evidence compels her to tighten the ambient air quality standards for ozone and particulate matter. "Hun­dreds of thousands of children are not

Ozone and particulate matter standards Current standard Proposed standard

Ozone 0.12 ppm measured over one hour

Particulate matter Regulates particles 10 μιτι or smaller in concentrations of 50 pg per cubic meter annually and 150 pg per eu m daily

0.08 ppm measured over eight hours

Regulates particles 2.5 μιτι and smaller in concentrations of 15 pg per eu m annually and 50 pg per eu m daily

Retains current 10-μιτι particulate standard

protected under the current standards but would be under EPA's proposals," she says. Opponents say that the propos­als are based on science that is equivocal at best—and junk at worst.

Senate Environment & Public Works Committee Chairman John H. Chafee (R-R.I.), a moderate on environmental is­sues, says the proposals may "push too far, too fast. . . . Frankly, there is reason to be worried about the health of the Clean Air Act." And in what may be to EPA the unkindest cut of all, even other agencies within the Clinton Administra­tion are highly critical of the standards.

But Browner has some staunch al­lies—for example, the American Lung Association, which sued EPA to force its review of the particulate matter stan­dard; the Sierra Club; and the Natural Re­sources Defense Council. These groups support the proposed revisions to the air standards but believe they don't go far enough.

Opposing any change in the standards is a multi-million-dollar coalition of large and small businesses, major industry, elec­tric power generators, and trade associa­tions. The 600-member Air Quality Stan­

dards Coalition has hired the best lobbyists in Washington, D.C., to turn legislators and the public away from the proposed standards. Lobbyist C. Boyden Gray, once counsel to President George Bush, is the power behind the coalition, as well as the leader of the industry-funded group Citi­zens for a Sound Economy. The member companies of the coalition have each con­tributed between $5,000 and $100,000 for the antistandards batde.

"The current proposal reflects such little understanding that it risks complete balkanization of industrial America," says Gray. I think it's really foolhardy. My ob­jection is not solely, or even predomi­nantly, on the cost side. Most of us have more problems with the fact that these standards just aren't justified. There's no need to rush. The standards may actually cause harm."

He explains: "If air conditioning is a method of screening out pollutants and neutralizing heat and humidity problems, then raising electricity costs is not a good thing to do. We know that people die because they cannot afford to keep their air conditioners going during peak peri­ods of the summer." Gray asserts that

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: Environmental Protection Agency • = rural, • = suburban, C

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APRIL 14, 1997 C&EN 1 1

Ozone levels are heading downward . . . . . . as are particle levels

n e w s focus

much of the ozone precursors and par­ticulate matter are emitted by coal-fired electric power plants. These facilities and consumers would have to bear much of the cost.

Browner may not be permitted to consider costs, but members of the Air Quality Standards Coalition certainly do. By any measure, the proposed regula­tions carry a big price tag.

Costs and benefits In terms of sheer cost, the proposed

standards are the largest regulatory ac­tion ever attempted by the agency. Browner estimates that the cost of imple­menting both standards would be ap­proximately $6.5 billion to $8.5 billion per year with annualized benefits of $120 billion. She says that the $120 bil­lion includes the workdays and school days that would be preserved and the re­duction in hospital admissions that would be achieved. Other benefits that would accrue don't have a dollar cost as­sociated with them. These are ecosystem protection, water quality protection, and improved visibility.

Browner says the particulate matter standard could save 15,000 lives per year by preventing premature deaths. Togeth­er, the standards would also prevent 250,000 incidences of respiratory symp­toms such as aggravated coughing and difficult breathing among children annu­ally. Although careful not to say that ozone or particulate matter causes asth­ma, Browner says adoption of the stan­dards would prevent 250,000 days of ag­gravated asthma each year.

"Asthma among our children has in­creased 118% between 1980 and 1993. It is the single greatest cause of childhood hospital admissions and among the lead­ing causes of missed days of school,'' Browner claims. In addition, she asserts that the standards would prevent 60,000 cases of bronchitis, 1.5 million cases of decreased lung function, and 9,000 hos­pital admissions annually.

EPA claims that more stringent air quality standards for ozone and ultrafine particles would produce health improve­ments for Americans far outweighing the costs. But even by EPA's own numbers, the health improvements realized would be slight for ozone, and the claimed ben­efits for ultrafine particles rest on shaky scientific assumptions.

The estimates of benefits due to re­duced mortality presented in EPA's regula­tory impact analysis are also controversial. Reduction in mortality contributes more

than 90% to that $120 billion in bene- ~ fits. EPA values reduction in mortality at $4.8 million per life regardless of how many years or days of life are lost. The benefit realized from avoid­ance of a case of bronchitis is $588,000. It adds up quickly.

The cost estimates are challenged by the American Petroleum Institute (API), among others, who say the annual cost of meeting EPA's pro­posed regulations is astronomical and would make a sizable dent in the average family's purchasing power. API claims, "The fine print reveals that [EPA's estimate] only pertains to a small portion of the to­tal costs because the agency only es­timated the costs of partial attain­ment and simply stopped counting when the costs began to rise expo­nentially.'' Hence, API believes the cost of reaching full compliance could be several times EPA's upper limit of $8.5 billion a year.

In fact, the President's Council of Eco­nomic Advisers estimates that the cost of fully attaining the proposed standard for ozone alone could be up to $60 billion per year—or more than the nation now spends on all air pollution abatement and control. The council's estimate indicates that an average American family of four would have its purchasing power re­duced by about $900 per year to pay for the ozone standard.

Proposed standards Although ozone in the upper atmo­

sphere is beneficial because it shields Earth from harmful ultraviolet rays, ground-level ozone damages lung tis- mmm

sue, reduces lung function, and sensi­tizes the lungs to other irritants.

Unlike other pollutants, ground-level ozone is not emitted directly into the air by specific sources. It is formed when volatile organic com­pounds (VOCs) and the oxides of ni­trogen (NOx) react on hot days in bright sunshine. Nitrogen oxides are produced by burning fossil fuels, mostly from highway vehicles and large industrial power plants such as those run by the electric utilities. VOCs are also produced by combus­tion, including burning gasoline in automobile engines, but they can come from paints and solvents. Large quantities of VOCs are pro­duced naturally by vegetation.

The proposed rules call for re­placing the standard for ozone of

Nearly all NOx derives from transportation, combustion

Chemical industrial

Nonchemical processes industrial

processes 3%

Miscellaneous 1%

Transportation 49%

Fuel combustion

46%

1995 NOx emissions : 21.8 million tons

Source: Environmental Protection Agency

0.12 ppm measured over one hour to 0.08 ppm measured over eight hours. For a locality to be in compliance, the average of the third highest reading in each year for three years cannot exceed 0.08 ppm. At this level, the proposed ozone standard is significantly more strin­gent than the present one-hour standard.

The chemical industry has consistent­ly produced between 1 and 2% of nitro­gen oxides and about 7% of VOCs over the past years. According to Joe J. May-hew, assistant vice president for environ­mental and policy analysis at the Chemi­cal Manufacturers Association, imple­mentation of the proposed ozone standard would require investment in low-NOx burners. However, indirect costs like electricity and transportation

VOCs are emitted mostly by industrial processes

pue l Miscellaneous combustion 2 % Nonchemical

3% \ \ industrial \ . \ processes

Chemical \ \ 5-jo/o industrial processes

7%

Transportation 37%

1995 VOC emissions : 22.9 million tons

Source: Environmental Protection Agency

12 APRIL 14, 1997 C&EN

Regulated particles come from various sources

35% 1995 particulates emissions =

2.55 million tons Source: Environmental Protection Agency

are probably bigger concerns for the chemical industry than direct costs," he says.

EPA is also seeking comment on sev­eral other options, including an ozone standard of 0.09 ppm measured over eight hours as well as a range of ozone concentrations from 0.07 ppm measured over eight hours to 0.12 ppm measured over one hour (the current standard). "EPA could adopt 0.09 with an eight-hour averaging time, and we'd be quite happy with that," says Mayhew. That eight-hour standard is roughly equivalent to the current one-hour standard.

The new standards would result in many counties being thrown into non­compliance, which can ultimately result in penalties such as state loss of federal highway funds. EPA projects that 335 counties, on the basis of their measured air quality from 1993 to 1995, would not meet the proposed ozone standard.

The other half of EPA's two-pronged proposal would set a national standard for very fine particulate matter, which comes largely from combustion sources like power plants and large incinerators. The chemical industry has consistently produced 3% of the nation's particulate matter emissions. In contrast, residential wood burning produces more than five times as much particulate matter by weight than does the chemical industry.

The proposed standard would, for the first time, regulate PM2.5—that is, parti­cles with diameters of 2.5 um and small­er, in concentrations of 15 μg per cubic meter annually and 50 μg per eu m daily. "This is the big-ticket item," says May-hew. "Controlling for fine particulate

matter in the chemical industry would require better electrostatic precipitators." He adds that the in­creased cost of electricity and fuel that would result from these stan­dards would be the most difficult for the industry to bear.

The current particulate matter standard regulates particles 10 um or smaller in concentrations of 50 μg per eu m annually and 150 μg per eu m daily. The 10-μηι standard would remain in place under EPA's proposal because data continue to indicate that these particles are harmful.

The proposed PM2.5 standard would throw considerably more ar­eas out of compliance than the exist­ing PM10 standard does. Under the proposed standard for fine particu­late matter, EPA projects that 167

counties would be out of compliance.

Particulates health effects To many, the science behind the pro­

posed standards is less than compel­ling—even for epidemiology—and sever­al prominent members of CASAC do not support the standards as proposed by Browner.

EPA began drafting its so-called crite­ria document—a collection of relevant peer-reviewed research on the health ef­fects of particulate matter—in the middle of 1994. "Recent criteria documents have become mammoth undertakings," says CASAC Chairman George T. Wolff, an atmospheric scientist from General Motors. "The first particulate matter cri­teria document published in 1969 sum­marized the relevant science in 220 pag­es. The final version of the present crite­ria document is a three-volume set containing over 2,400 pages."

Once the criteria document is com­piled, EPA then assembles its staff paper. This paper contains the agency's recom­mendations for the details of the stan­dard along with justifications that are drawn from material contained in the cri­teria document.

CASAC reviews of both the criteria document and staff paper are iterative pro­cesses that usually involve two to three re­visions to both of the documents before CASAC reaches a decision on the scientific merits of the proposals. In the past, the entire process has taken several years to complete. However, the particulate matter review was on an accelerated schedule be­cause of the court order. CASAC members have complained about being rushed.

The evidence implicating particulate matter as a cause of death is strong but largely circumstantial. It comes mostly from epidemiological studies that looked at the rates of death and disease within specific communities and attempted to correlate that information with levels of particulates in the air. What is clear is that as levels of particles go up, so do death rates, hospital admissions, emer­gency room visits, and asthma attacks. "As a consequence, there was a consen­sus among CASAC members that retain­ing an annual PM10 standard at the cur­rent level is reasonable at this time," says Wolff.

Two types of epidemiological studies related to particulate matter were cited by EPA and reviewed by CASAC. The first type was short-term acute mortality studies that compared daily particulate matter levels and mortality in a dozen or so locations around the U.S. "After filter­ing out or accounting for the effects of such things as season, day of the week, and meteorology on mortality, the re­maining statistical relationship between daily particulate matter levels and daily mortality was quantified," says Wolff. "Al­though this relationship varied from loca­tion to location, the average value was a 4% increase in daily deaths for a 50-pg-per-cu-m increase in PM10 concentrations."

The second type of epidemiological study followed the health of certain groups of individuals for a number of years in various locations around the country. In these studies, the annual mortality rate in a given location was re­lated to the annual average PM10 or PM2.5 concentrations after mortality rates were adjusted for smoking and oth­er potentially confounding variables.

According to Wolff, of the three stud­ies reported in the literature, two show a positive relationship between annual mortality and particulate matter and at­tribute two to three times the number of deaths to particulate matter as the short-term acute effect studies do. The third study, he says, shows no relationship be­tween particulate matter and mortality, but EPA dismissed this study for a num­ber of reasons, including its smaller sam­ple size.

EPA used the higher mortality esti­mates from the two studies to conclude that premature deaths can result from chronic exposure to particulate matter, in addition to deaths caused by acute ex­posures. EPA also concluded that the mortality was due to PM2.5 rather than larger particles within the PM10 fraction

APRIL 14, 1997 C&EN 13

Transportation 27% ^

Chemical industrial processes

3% Fuel combustion / 35%

Nonchemical industrial '

processes

news focus of air particulates, "but the evidence for this conclusion was ambiguous," says Wolff.

Nevertheless, 19 of 21 CASAC mem­bers voted to recommend that very fine particulate matter—PM2.5—be regulat­ed. However, the CASAC panel could not reach consensus about an appropriate ambient level at which this ultrafine par­ticulate matter should be regulated be­cause, according to Wolff, "Our under­standing of the health effects of particu­late matter is far from complete."

EPA recommended a daily PM2.5 stan­dard of 18 to 65 μg per eu m and an an­nual standard of 12.5 to 20 pg per eu m. Four panel members supported specific ranges within or near the lower end of EPA's recommendations. Seven members supported specific ranges or levels near, at, or above the upper end of EPA's rec­ommendations. Two members did not think a PM2.5 standard was warranted at all. The remaining eight panel members endorsed the concept of a PM2.5 stan­dard but declined to select a specific range or level. As a result, says Wolff, "only a minority of the panel members supported a range that includes the present EPA proposals."

Mary D. Nichols, EPA assistant admin­istrator for air and radiation, believes that getting scientists to commit to a specific level of air pollution control will always be difficult. She reflects on her experi­ence as head of the California Air Re­sources Board: "We set air quality stan­dards for California that in some cases were more stringent or ahead of the fed­eral government's, including an air quali­ty standard for lead and a PM10 standard.

"In every one of these cases," Nichols recalls, "I found that the scientists were never willing to tell you that they were

Gray: standards Just aren't Justified

1 4 APRIL 14, 1997 C&EN

Federal agencies question EPA's proposed air standards A number of federal agencies have raised serious questions about EPA's proposal to issue more stringent air quality standards for ozone and particulate matter. They claim EPA has underestimated the costs of its proposal and exaggerated the health benefits. For example: Department of Transportation. "There are substantial uncertainties . . . about the health effects [of more stringent standards]." It says that the proposed standards will cause "social and eco­nomic disruption," noting that they could "require lifestyle changes by a sig­nificant part of the U.S. population." It concludes that "it is incomprehensible that the Administration would commit to a new set of standards and new ef­forts to meet such standards without much greater understanding of the problem and its solutions." Small Business Administration. EPA's proposed regulation "is certainly one of the most expensive regulations, if not the most expensive regulation faced by small businesses in 10 or more years. . . . Considering the large economic im­pacts suggested by EPA's own analysis that will unquestionably fall on tens of thousands, if not hundreds of thou­sands, of small businesses, [EPA's pro­posal] would be a startling proposition to the small business community." It adds that its "concern is heightened by the large body of evidence suggesting the paucity of health benefits that would result from a revised standard."

Presidents Council of Economic Advisers (CEA). The "costs are high, and the [regu­latory impact analysis] understates the true costs of stricter [ozone] standards by orders of magnitude. . . . CEA estimates indicate that the cost of full attainment could be up to $60 billion [annually]." In addition, CEA's review of the evidence from EPA's scientific peer-review panel on ozone "reveals that the incremental health-risk reduction for more stringent standards is small . . . even for asthmatic children playing outdoors."

Office of Science & Technology Policy. "There are a large number of scientific uncertainties [about particulate pollu­tion]. . . . The database for actual levels of PM2.5 [ultrafine particles] is also very poor. . . . And current data do not sup­port clear associations of [particulate matter] effects with either fine particles (PM2.5), inhalable particles (PM10 or PM15), [or] sulfate, so that causality for the observed mortality and morbidity effects cannot be established."

Department of Treasury. On the basis of EPA's analysis, "it seems that many ar­eas cannot achieve the new [fine parti­cle] standard." It asks if that means com­plying with it would be "infeasible." On ozone, the department asks, "If [as CASAC stated] none of the proposals is significantiy more protective of public health, then why not choose the least restrictive?"

Department of Agriculture. "Farm groups have expressed their concern that the proposed standards may impose signifi­cant costs on farmers and agribusi­ness." Concerning EPA's economic anal­ysis, it says, "Benefits are based on full attainment of the proposed standards. Costs, however, do not reflect the full costs of attainment because some areas do not attain either the ozone or PM standard by 2007 using current control technologies."

Department of Commerce. It has "con­tinuing concerns" about the proposai It urges EPA to include "cost ranges for full compliance with proposed standards."

Department of Energy. EPA should con­sider "retaining the current primary [ozone] standard."

Office of Management & Budget Its con­cerns include the need for EPA to be more neutral about less stringent stan­dards and on the need to call for com­ment on retaining the current particulate matter standard. OMB also advises EPA to do a better job of calculating costs.

clear on what the exact level of the stan­dard ought to be. They were willing to say, This is how far our research goes, and as a personal matter, we think you should be regulating this compound, or that this is a problem that you should be addressing.' But they understood that the setting of the standard itself is really a complex risk management decision.''

Wolff believes that "the diversity of opinion expressed by the panel mem­

bers reflects the many unanswered ques­tions and large uncertainties associated with establishing the cause of the associ­ation between ultrafine particles and mortality.'' Most panel members were in­fluenced, to varying degrees, by these unanswered questions and uncertainties.

One of the major uncertainties stems from the paucity of data that actually measured PM2.5 as opposed to studies that measured PM10, estimated the frac-

tion of PM10 that is PM2.5, and extrapo­lated to human health effects. In addi­tion, very tiny particles are often contam­inated with other pollutants such as ozone, sulfur dioxide, or carbon monox­ide. Those chemicals—not the parti­cles—may be the real culprits.

The lack of a plausible biological mechanism for particulate matter toxici­ty troubled many of those presenting tes­timony before the Senate Committee on Environment & Public Works. And it also troubled most of the senators hearing the testimony.

Economist Anne E. Smith, vice presi­dent of Decision Focus, a Mountain View, Calif.-based risk assessment and management consulting firm, explained to the senators: "When we observe two types of data going up and down togeth­er, we should not necessarily conclude that there is a causal relationship be­tween the two phenomena. . . . When we have statistical evidence of the sort that seems to suggest that ambient par­ticulate matter and mortality go up and down together, we also want to have sci­entific data about biological processes as­sociated with particulate matter to help us explain why we should believe this is a causal relationship, and not just a statis­tical association."

She said that even EPA asserted in its criteria document that no credible data support particulate matter toxicity. And even when particulates were put into an­imals' lungs, no one could elicit consis­tent responses. Smith says this result is troubling, because "you might expect adverse changes to be readily observable in laboratory experiments if the health effects were as large as the statistics seem to suggest."

CASAC member Daniel B. Menzel, an environmental toxicologist who is pro­fessor and chairman of the department of community and environmental medi­cine at the University of California, Ir­vine, is skeptical because the studies show that all particles—no matter where they come from or what they're made of—have the same toxicity. Even though particles on the West Coast are mostly sulfuric acid and particles on the East Coast are mostly nitric acid, they have the same effect. "One of the basic tenets of toxicology is that toxicity occurs via chemical reaction," he says. "How then can the same effect result from very dif­ferent kinds of chemistries?" According to Menzel, "We must conclude that there is no plausible mechanism . . . that can account for the reported results."

Whether very fine particles are them­selves the cause of death and disease isn't as much of a concern to CASAC member Morton Lippmann, professor of environmental medicine at the Institute of Environmental Medicine at New York University. Lippmann does not claim PM2.5 to be the causal agent. Rather, he says, "PM2.5 is a better measure than any alternative metric of the complex in the particulate mass that is causing excess mortality and morbidity." Excess mortali­ty, hospital admissions for respiratory dis­eases, and decreased lung function are all more strongly and consistently associat-

Protester demonstrates against proposed EPA standards outside Senate building.

ed with ultrafine particles rather than with the larger fraction of PM10 parti­cles, he explains.

Nor is Harvard University epidemiolo­gist Joel Schwartz especially troubled by the prospect that EPA could be on the verge of regulating not the pathogen, but its harbinger. As far as he is concerned, all of the harmful particles, regardless of what they're made of, are generated by combustion. "Hence, control strategies to reduce exposure to fine particles will

never focus on a specific particle, they will focus on sources," he says.

Finally, recent reanalyses of the stud­ies cited in EPA's staff paper have includ­ed gaseous criteria pollutants in their models and have revealed that, in many cases, ozone, sulfur dioxide, or carbon monoxide can be as important as or more important than particles in describ­ing mortality. According to Ronald E. Wyzga, senior manager for air quality and risk at the Electric Power Research Insti­tute in Palo Alto, Calif., reanalyses do not support an association between unam­biguous particulate matter and health.

The results do not agree with the original investi­gators' conclusions of a significant association between particulate matter and health.

Any number of mod­els can be used to ana­lyze statistical data. Hence, a researcher's choice of a model can always be criticized af­ter the fact to call into question the results of an epidemiological study. That's the nature of epidemiology. Such statistical studies em­ploy models that are de­signed to correct for so-called confounders, vari­ables that can throw off a study's results. The myriad confounders in the particulate matter studies could include smoking, age, socioeco­nomic status, tempera­ture, humidity, or other pollutants, for example.

Wyzga took aim and fired at the models used by particulate matter re­searchers at a Senate hearing. He said that un­der contract to EPA, the

National Institute of Statistical Sciences, Research Triangle Park, N.C., reexam­ined daily mortality and particulate mat­ter relationships in Birmingham, Ala. "The reanalysis tried to ensure that the effect of hot, humid days is considered in any model trying to assess the influence of particulate matter on mortality. . . . When humidity is included among the meteoro­logical variables, the PM10 effect is not sta­tistically significant," explained Wyzga.

Wolff and Lippmann disagree with

APRIL 14, 1997 C&EN 15

n e w s focus & 7 '**•,• -

Chronology of controversy over EPA's proposed standards documents Nov. 27,1996-ΐΡΑ Administrator Carol M. Browner announces proposals de­signed to strengthen current ozone and particulate matter standards.

Dec. 10—In a letter to Browner, Sen. John H. Chafee (R-R.L), chairman of En­vironment & Public Works Committee, expresses opposition to proposed air quality standards. Chafee says the finan­cial impact should be factored into the standard-setting process for air quality issues. He also says, "A standard that cannot be implemented or that results in controls for the wrong aspect of a pollution problem will not protect pub­lic health, and may undermine support for efforts already under way."

Dec. 19—Groups representing state and local governments ask Browner for more time to comment on the standards.

Jan. 7, 1997—Senate Small Business Committee Chairman Christopher (Kit) Bond (R-Mo.) and ranking Democrat Dale Bumpers (Ark.) say in a letter to Browner that the agency did not comply with the new law requiring it to analyze the rule's potential economic impact on small business. EPA argues that ozone and particulates proposals, although significant enough to require such re­view during implementation, are not subject to the law during the rulemak­ing process.

Jan. 24—House Government Reform & Oversight Subcommittee on National Economic Growth, Natural Resources & Regulatory Affairs Chairman David M. Mcintosh (R-Ind.) requests information

about EPA compliance with procedural requirements under the Regulatory Flexibility Act, the Unfunded Mandates Act, and cost-benefit analyses mandated by Executive Order 12866. Feb. 10—Arizona district court denies EPA's request for a 60-day extension of the deadline for final particulate matter ambient air quality standard, but gives the agency three more weeks. The court says it will grant no more extensions.

Feb. 12—At a Senate hearing, Chafee tells Browner that the new rules could provoke a revolt against the Clean Air Act. He says he does not support the proposed ozone standard and backs a less stringent rule than EPA's proposal for ultrafine particles (PM2.5). Feb. 21—Browner tells a children's health conference that "when it comes to protecting our kids, I will not be swayed. If the science shows that we have to do more to ensure that our kids are safe from pollution, then that is ex­actly what we will do."

Feb. 25—Rep. Thomas J. Bliley Jr. (R-Va.), chairman of the House Commerce Committee, accuses EPA of trying to conceal an Office of Management & Budget review critical of the proposed rule. EPA turns over all requested docu­ments the next day.

March 4—Five coal-state senators—Rob­ert Byrd (D-W.Va.), John D. (Jay) Rock­efeller (D-W.Va.), Charles R. (Chuck) Robb (D-Va.), John Glenn (D-Ohio), and Wendell H. Ford (D-Ky.)—urge the Clin­ton Administration to stick with current

clean air standards. They ask EPA to "al­low states to complete action on the am­bitious clean air standards already in place." March 12—The public comment peri­od on the proposed standards closes. EPA reports that it received more than 17,000 letters, 3,000 e-mail messages, and 15,000 phone calls to a special toll-free number.

March 13—Washington Legal Founda­tion files petition with EPA seeking to disqualify Browner from further partic­ipation in rulemaking. The petition al­leges that Browner has made numerous public statements demonstrating that she has already made up her mind to adopt the new standards. "It is most un­fortunate that Ms. Browner appears to have prejudged the issue. She has de­prived the American public of a fully in­formed and fair debate on this impor­tant topic," says the foundation's execu­tive legal director, Paul Kamenar.

March 24—Sen. Byrd asks several feder­al agencies for their assessment of EPA proposals following allegations that the Clinton Administration quashed efforts by a number of agencies to comment on the proposals.

April 2—EPA admits it mistakenly over­stated the number of premature deaths preventable by the proposed particulate matter proposal The agency revises es­timate to 15,000 from 20,000 deaths.

July 19—EPA's deadline for making a fi­nal decision on the particulate matter standard.

each other on the validity of the assump­tion made in all of the acute studies that daily ambient particulate matter data col­lected from a centrally located air-monitor­ing site is representative of individual ex­posure to particulates. Wolff says the re­sults of studies exarnining this assumption are ambiguous, but Iippmann says that growing evidence indicates that particles are uniformly distributed.

When experts disagree about virtually everything, it's hard to figure out what to think. Ultimately, CASAC strongly recom­mended that EPA immediately imple­ment a targeted research program to ad­dress unanswered questions and uncer­tainties and also to get some long-term PM2.5 measurements.

Wolff believes there is plenty of time to do the research before setting stan­dards, noting that PM10 concentrations

have declined 22% from 1988 to 1995. Implementation of existing control pro­grams required by the 1990 Clean Air Act Amendments that target PM2.5 precur­sors (VOCs, NOx, and SO^, diesel partic­ulate matter emissions, and other prima­ry emission sources are the reason for the decline.

"This trend will continue for the fore­seeable future as additional measures re­quired by the amendments are phased in," Wolff says. He insists that there is time to conduct the research recom­mended by CASAC. And once questions and uncertainties have been clarified, "the appropriate PM2.5 standard could be established," says Wolff.

"EPA desperately needs to add to its understanding of how fine particulates really affect people so we can find what concentration would really protect peo­

ple," says CMA's Mayhew. "Our bottom-line advice to EPA on particulate matter is to go ahead and set a fine particulate matter standard, but don't set a level now—maybe set a range. Then set up a monitoring network. This will allow EPA to go ahead and pick the level later when [it has] more information." Mayhew be­lieves it will take about three years to set up the monitoring network, and about three years to collect data on PM2.5.

Nichols disagrees with those who would wait. She says that, even under the most expedited view of the Clean Air Act, it will be more than a decade before any standards have to be met. And EPA is expecting litigation and possible amend­ments to the law by Congress to draw the process out even further. She ex­plains that any child currently suffering under the current standards will be an

16 APRIL 14, 1997 C&EN

adult by the time the rules go into place if EPA waits until all of the data are in be­fore setting a standard.

Nichols explains that "setting a stan­dard is just a starting point for a plan­ning process. Research on control strat­egies, decisions on implementation, de­velopment of plans, and approval of plans all precede a final rollout of the regulatory requirement." Nichols be­lieves it is better to use the best exist­ing science to set a goal and then to re­fine that goal as more information be­comes available.

Roger O. McClellan, president of the Chemical Industry Institute of Toxicolo­gy, marvels at the paradoxical situation. "It appears," he says, "that the only way to get funding for more PM2.5 measure­ments is to get a PM2.5 standard. Thus, we are faced with the perverse situation of creating a standard to get scientific data rather than having a standard devel­oped based on solid scientific data." Based in Research Triangle Park, N.C., the institute is a not-for-profit research organization that assesses the human health risks of exposure to chemicals.

Ozone health effects Nichols insists that "ozone has been

researched from every angle that you could research. There isn't any debate in the science community about the quality or quantity of the science on ozone. The only issue that remains on ozone is what conclusion you draw from a policy per­spective from the data that exist."

CASAC looked at 185 of the latest studies of the effects of ozone on human health. All of them showed harmful ef­fects from ozone at the current regulated level. EPA selected "outdoor children" and "outdoor workers"—particularly those with preexisting respiratory dis­ease—as the appropriate populations to study because they would be the most vulnerable.

CASAC concurred that "ozone may elicit a continuum of biological respons­es down to background [which is about 0.04 ppm]," says Wolff. So, CASAC con­cluded that there is no "bright line" that distinguishes any of EPA's proposed stan­dards as significantly more protective of public health. "For example," says Wolff, "the differences in the proportion of out­door children responding [to levels] be­tween the present standard and the most stringent EPA proposal were small, and their ranges overlapped for all health endpoints." Consequently, CASAC re­ports, "the selection of a specific level

and number of allowable exceedances is I a policy judgment."

So why did EPA, as a matter of policy, propose to tighten the standard when even its advisory committee could see no difference in the health effects resulting from exposure to ozone at the current standard level and to exposure to ozone at the tightest standard proposed?

Nichols says Browner gave more weight to the opinions of those CASAC members who were health scientists, like physicians and epidemiologists, than she did to the opinions of those whose expertise was in areas like atmospheric chemistry or control technologies. Brown­er says EPA decided to propose the 0.08-ppm level because it was the lowest level recommended by individual CASAC panel members and because it was the lowest level tested and shown to cause effects in controlled human-exposure health studies.

"Given the uncertainties associated with this kind of complex health deci­sion, we believe that an appropriate goal is to reduce the number of people ex­posed to ozone concentrations that are above the highest level recommended by any of the members of the CASAC pan­el," Browner explains.

Wolff describes controlled human-ex­posure studies reviewed by CASAC. In these, individuals were exposed to ozone concentrations slightly above, at, or below the present standard, usually for six hours, while engaged in light to heavy exercise. Before, during, and after the exposure, the individuals' lung func-

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Smith: results are troubling

tions were monitored, and any symp­toms, including coughing, shortness of breath, or chest pain, for example, were recorded.

"These studies have produced two important results," says Wolff. First, no decreases in lung function were ob­served for people exposed for one or two hours while resting until ozone concentrations were greater than three times the present standard. But after people had been exercising for many hours, their lung function decreased even at concentrations below the present standard.

"This evidence suggests that an eight-hour standard is a better measure of re­sponse than a one-hour standard," Wolff says. All CASAC members voted to rec­ommend that EPA propose an eight-hour standard instead of a one-hour standard.

The hospital admission studies for ozone examined the relationships be­tween daily ozone concentrations and daily hospital admissions for respiratory problems. "These studies have consis­tently shown an apparent linear relation­ship in various North American locations between ozone and the admissions, and EPA has assumed that this relationship is cause and effect," says Wolff. The rela­tionship held even for exposures to ozone at concentrations below the present standard. "There is no evidence of a threshold concentration, and this re­inforces the conclusion from the field studies," Wolff says.

According to George D. Thurston, as­sociate professor of environmental medi­cine at New York University's School of Medicine, "Studies have shown compel­ling and consistent evidence of adverse effects by ozone below the current U.S. standard."

Both population-based epidemiologic studies, in which an entire city's popula­tion might be considered in the analysis, and cohort studies, in which selected in­dividuals—such as a group of asthmat­ics—are considered, have confirmed the association between exposure to ozone air pollution and increasing numbers of adverse impacts, Thurston explains.

One of the field studies Thurston of­fers as evidence that ozone is harmful to human health is his own study, which is quite controversial. In summer camps, asthmatic children, engaged in the nor­mal physical activities that occur at these camps, participated in lung function test­ing, and the results were compared to the ambient ozone concentrations.

"This study of a group of moderately

APRIL 14, 1997 C&EN 17

to severely asthmatic children shows that these children experience diminished lung function, increased asthma symp­toms, and increased use of unscheduled asthma medications as ozone pollution levels rise," says Thurston. "On the high­est ozone days, the risk of a child having an asthma attack was found to be ap­proximately 40% greater than on an aver­age study day, with these adverse effects extending to below 120 ppb ozone," he says.

Thurston based his conclusion on a study of 166 children (ages seven to 13) attending an "asthma camp" downwind of New York City during the last week of June 1991 (52 children ), 1992 (58 chil­dren), and 1993 (56 children). He found that there were, on average, 20 unsched­uled uses of medication each day among each group of children. On the day with the highest level of air pollution, there were 28 unscheduled uses. Thurston at­tributes this entire increase in unsched­uled medication use to air pollution.

In terms of health effects, this would mean that on the day with the most air pollution, one in seven moderately to se­verely asthmatic children would use their medication one extra time per day, and one in five moderately to severely asthmatic children would have one addi­tional respiratory symptom per day. Thurston and EPA find this information compelling. But others don't.

"On their face, these results demon­strate that air pollution is not the severe health threat that EPA and the American Lung Association would have us be­lieve," says Steven J. Milloy, who is an at­torney, health scientist, biostatistician, crusader against "junk science," and a consultant on environmental risk man­agement. "But do they establish that air pollution caused even the effects ob­served?"

Milloy points out that Thurston col­lected data on relative humidity and pollen and found that neither signifi­cantly correlated with adverse health ef­fects. "However, changes in tempera­ture, atmospheric pressure, dust, fumes, and food preservatives may also exacerbate asthma," he says. "But the researchers did not consider any of these risk factors."

Milloy says asthma is "easily and com­monly exacerbated by anxiety . . . but these researchers ignored this potentially important confounding risk factor." He illustrates: "Imagine being a 10-year-old at 'asthma camp' where the buzz' around camp is about the latest pollution

18 APRIL 14, 1997 C&EN

Nichols: Clean Air Act says "we care. "

readings. Pollution levels increase. Kids get anxious. Airways constrict. Unsched­uled medication use increases."

Other studies have analyzed summer­time daily hospital admissions of patients with respiratory symptoms. These stud­ies show a positive relationship with am­bient levels of ozone. Some studies sug­gest that these associations remain even after controlling for temperature, aller­gens, and other pollutants.

Research conducted by Thurston and reviewed by CASAC projected in­creases in hospital admissions of asth­matics in the New York City area for various ozone air quality standards. The research projected that there would be 100 fewer potential hospital admissions for respiratory symptoms attributable to ozone in excess of background levels if the current standard were tightened to a standard very close to EPA's proposal. However, the 100 fewer admissions are a tiny fraction of the 28,195 asthma ad­missions in New York City each year. Whether this is an important benefit de­pends on whether you're one of those 100 people.

"Based on the available health evi­dence, the vast majority of the public is not in danger of noticeable health effects from current air quality in most U.S. cit­ies," says Kenneth W. Chilton, director of the Center for the Study of American Business in St. Louis. "Certainly, it is not clear at this time that a new, more strin­gent ozone standard is needed."

Nevertheless, Nichols maintains, "the data are absolutely clear that ozone caus­es cellular damage in humans. They are absolutely clear that there are short-term

effects on lung function, on people's ability to breathe. It affects people's abil­ity to do work; it affects people's suscep­tibility to colds, respiratory infections, and coughs; and it triggers asthma at­tacks in people who have asthma."

"There's no dispute about cause and effect," Nichols says. "We know it's ozone. We measure the ozone; we mea­sure the people or the [test] animals. The only dispute is about whether we ought to care as a country. And we think the Clean Air Act tells us, yes, we care."

Nichols insists that the decision on whether to revise the standards has not been made and probably will not be made until very close to the court-imposed deadline of July 19. "It is impor­tant for people to understand that, in putting out the proposals, the agency used CASAC and relied on review by CASAC of a variety of peer-reviewed sci­entific documents," she says. "CASAC, by overwhelming consensus, did tell us to set standards, even if it didn't tell EPA precisely where to set the standards." Nichols says EPA has proposed the ratio­nale that it believes is the most convinc­ing for where those standards should be set.

"We are compelled to review the standards; we are not compelled to change them, except if the evidence is convincing," Nichols explains. The sci­entific evidence that was available when the standards were proposed convinced EPA that there was a good reason to change them. "Those who are trying to create an impression that EPA is out there on its own trying to ratchet up standards so it can justify increasing its budget are really doing the whole debate a disservice," she says.

"Why are they rushing to do some­thing when they could easily take three to five years to do some research, which they say they badly need to resolve the great uncertainties?" asks Gray. "EPA be­ing sued by the Lung Association gives the agency the excuse to do this now, but the only thing the lawsuit says is that you have to make a decision one way or the other. The lawsuit doesn't require EPA to implement the standards," he adds.

"I'm really not a zealot," says Nichols. "And I'm not a person who believes in jumping off of cliffs. I think we have the weight of the facts on our side, and we have the overall public interest on our side. And if at the end of the day the pro­posal is modified slightly, it's not a defeat and it's not the end of the world."^

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