Council Confirms Link between Ozone Pollution and Premature Death
Short-term exposure to current levels of ozone in many areas is likely to contribute to premature deaths, says a new National Research Council report, which adds that the evidence is strong enough that the U.S. Environmental Protection Agency should include ozone-related mortality in health-benefit analyses related to future ozone standards. The international committee that wrote the report was not asked to consider how evidence has been used by EPA to set ozone standards, including the new public health standard set by the agency last month.
Ozone, a key component of smog, can cause respiratory problems and other health effects. In addition, evidence of a relationship between short-term--less than 24 hours--exposure to ozone and mortality has been mounting, but interpretations of the evidence have differed, prompting EPA to request the NRC report. In particular, the agency asked the committee to analyze the ozone-mortality link and assess methods for assigning a monetary value to lives saved for the health-benefits assessments. Based on a review of recent research, the committee found that deaths related to ozone exposure are more likely among individuals with pre-existing diseases and other factors that could increase their susceptibility. However, premature deaths are not limited to people who are already within a few days of dying.
The committee, chaired by University of Chicago Professor Emeritus John C. Bailar III, examined research based on large population groups to find how changes in ozone air concentration could affect mortality, specifically to determine the existence of a threshold--a concentration of ozone below which exposure poses no risk of death. The committee concluded that if a threshold exists, it is probably at a concentration below the current public health standard. As people have individual susceptibilities to ozone exposure, not everyone may experience an altered risk of death if ozone air concentration also changes. Further research should explore how personal thresholds may vary and the extent to which they depend on a person's frailty, the committee said.
Copies of "Estimating Mortality Risk Reduction and Economic Benefits from Controlling Ozone Air Pollution" are available from the National Academies Press, tel. 202-334-3313 or 1-800-624-6242 or on the Internet at www.nap.edu.