The bottom line: the standard set by the Bush administration (and later backed by the Obama White House against the advice of EPA and the agency’s independent science advisers) simply doesn't cut it.
This assessment notes that recent studies bolster the case for a tougher new national smog standard. EPA had backed a tougher standard even before the new evidence came in. (The Obama Administration is currently in court defending the Bush standard.)
Because of political meddling by the Obama White House and its former "regulatory czar" Cass Sunstein, breathers will be paying the painful price of smog until at least 2014, when EPA completes its evaluation of this issue.
Here is a link to the new EPA assessment:
And here are a few key excerpts, with a little emphasis that we added to key points:
With regard to the scientific evidence related to short-term O3 exposures as considered above (section 4.2.1), we reach the preliminary conclusion that the available evidence clearly calls into question the adequacy of the current standard and provides strong support for considering potential alternative standards to increase public health protection, especially for at
risk groups. This preliminary conclusion places considerable weight on the array of O3-related respiratory effects that have been reported following short-term exposures to O3 concentrations below the level of the current standard, including clear evidence from controlled human exposure studies of lung function decrements, respiratory symptoms and pulmonary inflammation, as well as evidence of clearly adverse effects from epidemiologic studies, including respiratory hospital admissions and emergency department visits, and premature mortality. Staff believes that this body of scientific evidence is very robust, recognizing that it includes large numbers of various types of studies, including toxicological studies, controlled human exposure studies, and community epidemiological studies, that provide consistent and coherent evidence of a causal relationship between short-term O3 exposures and an array of respiratory morbidity and mortality effects, especially for at-risk populations. Moreover, the evidence supports a likely causal relationship between short-term O3 exposures and non-accidental and cardiopulmonary
mortality. ... in staff’s view the broad array of health effects reported following exposures to O3 concentrations below those allowed by the current standard (i.e., respiratory effects and mortality), combined with the plausible linkages between these effects and the much larger body of epidemiologic and controlled human exposure evidence at higher O3 concentrations, supports the appropriateness of considering revising the current O3 standard in order to increase public health protection against adverse health effects from short-term O3 exposures, particularly for
children, older adults, people with asthma, and for other at-risk groups...
With regard to CASAC advice (section 4.2.3), we note that the CASAC O3 Panel has repeatedly recommended setting the level of the 8-hour O3 standard no higher than 70 ppb, within a range of 60 to 70 ppb, which is below the level of the current standard (i.e., 0.075 ppm or 75 ppb). Since this advice was provided, based on evidence available in the last review, the evidence for adverse health effects following short-term exposures to O3 concentrations below 75 ppb has become even stronger, with the addition of several controlled human exposure and epidemiologic studies conducted at relatively low O3 concentrations. Given this, we note that, at a minimum, nothing in the recent evidence would contradict CASAC’s previous advice and that, in fact, recent evidence provides stronger support for that advice.
In light of all of the above considerations, staff reaches the preliminary conclusion that the body of information now available supports consideration of revising the current 8-hour O3 primary standard, so as to afford greater public health protection against the adverse health effects of short-term O3 exposures, especially to at-risk groups, and that it does not support retention of the current standard. In so doing, we also recognize that consideration should be given to the extent which such a revised standard would also provide appropriate protection against the adverse health effects of long-term O3 exposures.