Pulmonologist, risk analyst clash over EPA ozone proposal in House hearing 

Source: Amanda Peterka, E&E reporter • Posted: Friday, June 19, 2015

A House hearing on air pollution turned contentious yesterday as two scientists attempted to sway lawmakers on the potential benefits — or lack thereof — of curbing ground-level ozone.

A risk analyst appearing for Republicans said reductions in smog-forming gas have not led to any public health improvements. Louis Anthony Cox, president of Denver-based Cox Associates, accused U.S. EPA of using subjective judgments and inaccurate models to conclude its proposal to tighten the current standard would save lives and lead to health benefits.

But Gregory Diette, a professor of medicine at Johns Hopkins University, countered that scientific evidence has grown stronger in recent years to support the need for a tighter standard.

“We seem to have a scientific standoff, if you will, as to these two competing hypotheses,” said Rep. Michael Burgess (R-Texas), chairman of the Energy and Commerce Subcommittee on Commerce, Manufacturing and Trade, which co-hosted the hearing with the Energy and Power Subcommittee.

Diette slammed the notion that researchers were split over whether a tighter standard would produce such health benefits.

“Just because there’s two of us there doesn’t mean there’s a 50-50 balance,” he said. “I think the scientific community is strongly behind lowering the standard.”

More than 1,000 health and medical professionals from all 50 states wrote EPA in March that controlled human exposure studies have showed even some healthy adults experience reduced lung function and airway inflammation at exposure levels of 60 parts per billion and higher.

This was the second Energy and Commerce hearing in the course of a few days on EPA’s November proposal to tighten the ozone standard of 75 parts per billion — set in 2008 during the George W. Bush administration — to between 65 and 70 ppb. Acting EPA air chief Janet McCabe testified before the Energy and Power Subcommittee last Friday (Greenwire, June 12).

While much of yesterday’s hearing focused on the potential costs to manufacturers of tightening the ozone standard, risk assessments played a key role.

At issue were EPA’s conclusions about the links between ozone pollution and public health. The agency says a new standard is needed in light of a scientific review that concluded the 75-ppb limit was no longer adequate to protect public health.

EPA says reducing ozone to its proposed range would prevent between 750 and 4,300 premature deaths, between 1,400 and 4,300 asthma-related emergency room visits, and between 320,000 and 960,000 asthma attacks in children yearly by 2025. A tighter standard would also result in a reduction of up to 1 million missed school days and 180,000 missed work days.

Cox said EPA’s predictions of public health benefits were both “unwarranted and exaggerated.”

“Ozone levels have already fallen in recent decades by far more than the proposed amounts in many locations in the United States,” he said. “Yet analysis of public health records shows that these large reductions in ozone levels have caused no detectable public health benefits.”

While he acknowledged there was a statistical association between declining ozone levels and health benefits, Cox argued that mortality rates declined just as quickly between 2000 and 2010 in areas where ozone increased as in areas that concentrations of the gas decreased.

EPA, he argued, has failed to account for large uncertainties in their models that project public health benefits. He also said the agency came to its conclusions about health based on subjective opinions and that the agency conflated scientific correlations with causations.

“This fundamental error, treating correlation as causality, invalidates EPA’s entire risk analysis and its conclusions,” he said.

Diette told lawmakers that as a pulmonologist he was better suited to evaluate public health effects of ozone.

Ozone, he said, was bad for both people who have lung disease and otherwise healthy people, as well. He argued that research has shown that each incremental rise in ozone exposure leads to severe asthma exacerbations, emergency room visits and hospitalizations.

The American Thoracic Society, on whose behalf Diette was testifying, has recommended a standard no higher than 60 ppb since the last review of the ozone standard.

The science since that initial recommendation “has been supplemented by an even greater understanding of the health effects of ozone exposure, including higher rates of respiratory disease in infants and children, reduced lung function and increased mortality in adults,” Diette said. “Indeed, there is clear, consistent and conclusive evidence that we believe should compel EPA to establish an ozone standard no higher than 60 ppb.”

Diette brushed aside Cox’s conclusion that reducing ozone levels hasn’t led to better health across the country as a whole.

“I think the world has mostly moved beyond this question,” he said. “This isn’t something we should be talking about in 2015, about whether ozone impacts public health.”