U.S. EPA is defending its choice of setting a new national ozone standard at 70 parts per billion despite blistering criticism by health and environmental groups that it won't protect the public.
EPA Administrator Gina McCarthy said that, while there's no "bright line" on where a standard should be set, she based the 70 ppb limit on a review of the best available public health science. The limit would protect the public with an adequate margin of safety, as is required by the Clean Air Act, McCarthy asserted.
"I need to do what is requisite: not too high and not too low, and it's very challenging," she said. "There's no bright line, but I used as much thought and reason on how we could actually identify health impacts that we could eliminate."
But public health and clean air advocates have accused EPA of dodging questions about its decision and of ignoring scientific advice to set a standard at 60 ppb. They're almost certain to file a lawsuit challenging the final rule (Greenwire, Sept. 29).
"This appears to be an arbitrary decision in search of a rationale," said Frank O'Donnell, president of Clean Air Watch.
EPA yesterday finalized the new standard. While it represents a tighter limit than the 75 ppb standard set in 2008 during the George W. Bush administration, it's the upper end of the range that the agency proposed last November.
In rolling out the rule, EPA said that, excluding California, limiting ozone concentrations to 70 ppb will save up to 660 lives, prevent 230,000 asthma attacks in children and prevent 630 asthma-related emergency visits by 2025. In California, the new standard will prevent up to 220 premature deaths, 160,000 asthma attacks in children and 380 asthma-related hospital visits (E&ENews PM, Oct. 1).
Top EPA officials yesterday said they based the standard on definitive scientific findings that 72 ppb is the lowest ozone exposure that causes adverse health effects in healthy, exercising adults. Those health effects include decreased lung function and increased respiratory symptoms.
McCarthy said that, after identifying 72 ppb as harmful exposure, she considered what standard would provide the public with an adequate margin of safety.
"We must protect all people from this level of exposure -- including kids, people with asthma, older Americans, and those who are active and work outside," McCarthy said. "So the standard needed to be lower than 72 ppb."
According to EPA, the science gets more uncertain as exposure levels go down. So the agency settled on 70 ppb as providing the best protection.
"The science is clear at 72 that the effects are harmful, are adverse, as those terms have been defined," EPA acting air chief Janet McCabe told public health groups on a briefing call yesterday. "And the science is less certain at levels below 72 that the effects that one sees in the studies are adverse."
The decision to set a 70 ppb standard comes after the Obama administration considered setting a 65 ppb standard in 2011. But the White House pulled the plug on a revision to the standard that year in the face of the upcoming 2012 election.
McCarthy yesterday defended her decision to differ from her predecessor, Lisa Jackson, who was at the helm of EPA at the time of the scuttled standard and who had made ozone pollution a priority.
"I have a little bit of advantage, so I apologize to Lisa Jackson," McCarthy said. "There's a lot more health data available today than she had available. We have 1,000 more studies in this package for us to look at that wasn't available to her."
McCarthy said that those studies included a "very definitive" study linking ozone exposures of 72 ppb to adverse health effects, as well as several studies that examined the potential impacts of a 60 ppb standard.
"When you look at these studies, as I did when making my decision," she said, "I think it was very clear to me that 70 was the standard where we should land."
Enviros see 'sleight of hand'
Public health and environmental groups, however, are accusing the agency of ignoring the recommendation of its own scientific advisers, as well as the advice of the nation's leading medical groups.
"The level chosen of 70 parts per billion (ppb) simply does not reflect what the science shows is necessary to truly protect public health," American Lung Association President and CEO Harold Wimmer said in a statement yesterday.
The agency's Clean Air Scientific Advisory Committee, a panel made up of outside experts who study air pollution, recommended in June 2014 that the agency choose a new standard in the range of 60 to 70 ppb after intense debate over whether 70 ppb would offer enough protection against adverse health effects.
CASAC noted in its official recommendation to the agency that it preferred a new standard near the lower end of the range (E&ENews PM, June 4, 2014).
"Obviously we were disappointed in the 2008 decision from this previous administration where CASAC's advice to the agency was essentially ignored," said Brian Urbaszewski, director of environmental health programs at the Respiratory Health Association. "And looking at the advice that CASAC has given to the agency this time around, it looks to a certain extent that that is still going on."
Top EPA officials say they took the scientific advisory group's advice into account.
"I have to disagree that CASAC is being ignored. CASAC clearly recommended a range of 60 to 70," McCabe said. "They acknowledged that the decision about the adequate margin of safety was a policy decision, that it is the administrator's to make. And that's what she did."
Public health advocates contend that the evidence linking 60 ppb exposures of ozone to negative health effects has grown more certain over the years.
The nation's leading public health organizations had recommended that EPA set a new standard no higher than 60 ppb.
John Walke, the Natural Resources Defense Council's clean air director, wrote in a scathing email that EPA's explanation of how it came to a 70 ppb standard "falls apart in the face of multiple lines of inconvenient arguments."
"EPA acknowledged that they found effects below 70 'but it was less clear whether those effects were adverse'? So EPA would have the public believe the effects of smog below 70 ppb are beneficial?!" he said.
He also charged that EPA gave less weight in its final rule to epidemiological studies that have found negative health effects associated with levels lower than 70 ppb.
Public health and environmental groups say EPA is missing an opportunity to save more people from asthma attacks and premature death.
According to EPA's regulatory impact analysis from last November, a standard of 65 ppb would prevent 960,000 child asthma attacks, or about three times the amount than a 70 ppb standard. A 60 ppb standard would prevent 1.8 million child asthma attacks.
In that analysis, EPA also found that a tighter standard would prevent hundreds more premature deaths than a 70 ppb standard.
EPA's McCarthy said that the nation should strive to lower ozone levels below 70 ppb but that the standard would be fully protective of children and older adults because it would result in ozone levels lower than the standard most of the time.
According to McCarthy, the standard would protect more than 98 percent of children from repeated exposures to ozone as low as 60 ppb.
"I'm confident that we're not only getting the elimination of health effects that we saw at 72," she said, "but also really robust reductions of repeated exposures."
Walke called that reasoning a "sleight of hand."
"EPA's sleight of hand pointing to reduced exposure levels among children in order to obscure or justify acceptance of an unprotective smog standard for those still exposed," he said, "is in some ways the most damning and telling indictment of the Obama administration's unsafe decision."
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