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Smog can kill, say scientists
23/04/2008 12:00 - (SA)
Washington - Short-term exposure to smog, or ozone, is clearly linked to premature deaths that should be taken into account when measuring the health benefits of reducing air pollution, a US National Academy of Sciences report concluded on Tuesday.
The findings contradict arguments made by some White House officials that the connection between smog and premature death has not been shown sufficiently, and that the number of saved lives should not be calculated in determining clean air benefits.
The report by a panel of the Academy's National Research Council says government agencies "should give little or no weight" to such arguments.
"The committee has concluded from its review of health-based evidence that short-term exposure to ambient ozone is likely to contribute to premature deaths," the 13-member panel said.
It added that "studies have yielded strong evidence that short-term exposure to ozone can exacerbate lung conditions, causing illness and hospitalisation and can potentially lead to death".
The White House Office of Management and Budget, which in its review of air quality regulations has raised questions about the certainty of the pollution and mortality link, did not immediately return a phone call seeking comment.
"The report is a rebuke of the Bush administration which has consistently tried to downplay the connection between smog and premature death," said Frank O'Donnell, president of Clean Air Watch, a Washington-based advocacy organisation.
Vickie Patton, deputy general counsel for the Environmental Defence Fund, said the Academy's findings "refutes the White House scepticism and denial" of a proven link between acute ozone exposure and premature deaths. Such arguments have been used to diminish the health benefits of reducing air pollution, she said.
More studies needed
The Academy panel examined short-term exposure - up to 24 hours -to high levels of ozone, but said more studies also were needed on long-term chronic exposure where the risk of premature death "may be larger than those observed in acute effects studies alone".
Ground-level ozone is formed from nitrogen oxide and organic compounds created by burning fossil fuels and is demonstrated often by the yellow haze or smog that lingers in the air. Ozone exposure is a leading cause of respiratory illnesses and especially affects the elderly, those with respiratory problems and children.
While premature death from ozone exposure is greater among individuals with lung and heart disease, the report said such deaths are not restricted to people who are at a high risk of death within a few days.
The scientists said they could not determine, based on a review of health studies, whether there is a threshold below which no fatalities can be assured from ozone exposure. If there is such a point, it is below the ozone levels allowed for public health.
Environmentalists and health advocates have argued that a string of health studies and surveys show that exposure to smoggy air not only aggravates respiratory problems, but causes thousands of deaths a year.
But in a number of instances the EPA and the White House Office of Management and Budget, which reviews regulations, have been at odds over the certainty of a link between smog levels and deaths.
Patton said the OMB in a number of air pollution regulations has sought to minimise the relationship of pollution and premature deaths, resulting in a lower calculation of health benefits from pollution reductions.
"This has been used by industry to try to attack health standards by minimising the societal benefits," said Patton.
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