Friday, September 30, 2011

EPA scientists: Yes, Mr. President, smog can kill!

You will recall the EPA was recently bushwacked by the White House on the smog issue.

But the EPA scientists continue to work away on the issue, with plans at this point to make a decision on national smog standards by mid-2014. (Yes, we know the President said 2013, but he was wrong.) That deadline, of course, could slip if politics intervene again.

As part of its ongoing review, EPA today published the “second draft" of its “integrated science assessment” of smog and its impacts.

You can find it here:

The bottom line: smog not only hurts your health – it can kill. It also poisons the environment and is a potent greenhouse gas.

So even though the President was concerned about the economics of smog control (forgetting that pollution cleanup creates jobs), this report is a graphic reminder that smoggy air carries a terrible health and environmental cost. Senior citizens in particular ought to take note! Your life could be getting cut short while this review continues.

In a quick “background” cover note, EPA states:

New material has been included in this draft, but many of the overall conclusions remain generally the same as the last NAAQS review which was completed in 2008. For example, in relation to short-term exposures, new evidence for O3-induced health effects strengthens the body of evidence for associations with respiratory morbidity and mortality. Also, the current ambient O3 concentrations in many areas of the US are sufficient to impair growth of numerous plant species. Within an ecosystem, O3 can alter timber production, water availability in watersheds and carbon sequestration; and, it can affect ecosystem biodiversity. In addition, as was concluded in the last NAAQS review, O3 can affect the climate by acting as a climate-forcing greenhouse gas. In contrast to the last review, there is now evidence suggesting that respiratory morbidity and mortality are associated with O3 long-term exposure.
Some key conclusions:

The clearest evidence for human health effects associated with exposure to O3 is provided by studies of respiratory effects. Collectively, there is a very large amount of evidence spanning several decades in support of a causal association between exposure to O3 and a continuum of respiratory effects. The majority of this evidence is derived from studies investigating short-term O3 exposure (i.e., hours to weeks), although animal toxicological studies and recent epidemiologic evidence demonstrate that long-term exposure (i.e., months to years) may also be detrimental to the respiratory system. Additionally, consistent positive associations between short-term O3 exposure and total (nonaccidental) mortality have helped to resolve previously identified areas of uncertainty in the O3-mortality relationship, indicating that there is likely to be a causal relationship between short-term exposures to O3 and all-cause mortality. Recent evidence is suggestive of a causal relationship between long-term O3 exposures and mortality. The evidence for these health effects indicates that the relationship between concentration and response is linear within concentrations present in the U.S., with no indication of a threshold of O3 concentrations under which no effect would be observed. The populations identified as being most at risk for O3-related health effects are individuals with influenza/infection, individuals with asthma, and older age groups.

There has been over 40 years of research on the effects of O3 exposure on vegetation and ecosystems. The best evidence for effects is from controlled exposure studies. These studies have clearly shown that exposure to O3 is causally linked to visible foliar injury, decreased photosynthesis, changes in reproduction, and decreased growth. Recently, studies at larger spatial scales support the results from controlled studies and indicate that ambient O3 exposures can affect ecosystem productivity, crop yield, water cycling, and ecosystem community composition. And on a global scale, tropospheric O3 is the third most important greenhouse gas, playing an important role in climate change

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