Monday, May 12, 2014

Draft Letter from EPA Science Advisers: Current National Smog Standard is Too Weak; TBA How Tough We Think It Should Be

As you may recall, EPA's science advisers have begun reviewing the science behind EPA's national clean air standards for ozone. When we last left the scientists, they had not firmed up an official recommendation to EPA's political leadership .

The scientists will reconvene May 28.  Ahead of that meeting, they have begun to review a draft letter of recommendation, and the draft is very revealing .

Although this is not official policy or recommendation, the draft does suggest a consensus on one point: that the current national smog standard, 75 parts per billion set by EPA in 2008, is too weak.  Yet to be determined: exactly how tough a new standard should be.  The draft does note that the tougher a standard is, the more premature deaths would be prevented.  And that there is evidence that asthmatic children would benefit from a much improved standard.

This draft letter is in response to a draft EPA "policy assessment," concluded that the current standard of 75 should be toughened to somewhere between 60 and 70.  Here are a few quick excerpts from the draft letter:
The CASAC [science advisory panel] finds scientific justification that current evidence and exposure/risk information call into question the adequacy of the current standard. Furthermore, there is scientific support for the need to revise the standard to achieve additional public health protection...

[Note to the Reader: At this time, the Panel is still deliberating regarding its advice for a scientifically based upper bound to the range of levels being considered for the primary [health]standard. The Panel will deliberate on the science-based upper level  during its upcoming teleconferences and will revise this response to the charge question."]...

Regarding EPA's staff recommendation that a standard could be set as tough as 60 ppb:
The CASAC concurs that 60 ppb is an appropriate and justifiable scientifically based lower bound for a revised primary standard. This is based upon findings of adverse effects, including clinically significant lung function decrements and airway inflammation, after exposures to 60 ppb ozone in healthy adults with moderate exertion (Adams 2006; Schelegle et al. 2009; Brown, 2008; Kim et al., 2011), with limited evidence of adverse effects below 60 ppb. The CASAC further notes that clinical studies do not address sensitive subgroups, such as  children with asthma, and that there is a scientific basis to anticipate that the adverse effects for such subgroups are likely to be more significant at 60 ppb than for healthy adults.

The draft clearly states that adverse health effects take place at ozone exposure levels even of 70 ppb -- the standard then-EPA Administrator Lisa Jackson tried to set   in 2011 until President Obama ordered her to stand down -- and that a standard of 65 would provide superior health protection than a a standard of 70:
...controlled human exposure studies show respiratory symptoms combined with clinically significant lung function decrements following ozone exposures to 60 ppb to 70 ppb in healthy individuals. These findings suggest that ozone exposures of 70 ppb pose significant concern, especially for children, asthmatics, the elderly and other at risk populations. Eight-hour ozone exposures (in the form of the current standard) at levels less than 70 ppb have also been shown to be harmful to human health, although to a lower percent of the population and with overall less severity as compared to what would occur at 70 ppb. An alternative standard level of 65 ppb would reduce the frequency of occurrence of lung function decrements of 15% or higher, as compared to a level of 70 ppb, but does not eliminate such occurrences. Further, an alternative standard level of 65 ppb would lead to lower frequency of short-term and long-term premature mortality than the current standard or a level of 70 ppb. The frequency of lung function decrements and premature mortality decreases even further when the alternative standard is lowered to 60 ppb. As noted earlier, based on results for clinical studies of healthy adults, and scientific considerations of differences in responsiveness of asthmatic children compared to healthy adults, there is scientific support that 60 ppb is an appropriate exposure of concern for asthmatic children.

I think it is a pretty safe bet that the oil industry and other polluters will rev up their campaign to block tougher standards.  This is shaping up to be a battle of polluter profits versus children's health.
We'll see what the scientists say when they reconvene May 28.  They can't delay too long because EPA now is under a court directive to propose a decision by December.



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