"Exposure to ... ozone is widespread in the United States," according to background information in the article. "Short-term exposure to ozone has been linked to adverse health effects, including increased rates of hospital admissions and emergency department visits, exacerbations of chronic respiratory conditions (e.g., asthma), and decreased lung functioning." Information on an association between ozone and death rates has been inconclusive.
Michelle L. Bell, Ph.D., from the School of Forestry and Environmental Studies, Yale University, New Haven, Conn., and colleagues investigated the effect of short-term (daily and weekly) exposure to ozone on death rates in the United States. Using information from the National Morbidity, Mortality, and Air Pollution Study (NMMAPS), the researchers estimated the average of deaths associated with short-term ozone exposure for 95 large urban communities (which includes 40 percent of the U.S. population) from 1987 to 2000.
The researchers found that a 10-ppb (parts per billion) increase in the previous week's ozone was associated with a 0.52 percent increase in the daily death rate, with a 0.64 percent increase in cardiovascular and respiratory-related deaths. People aged 65 to 74 years old experienced a slightly higher increase in the death rate, at 0.70 percent. Results were significant when adjusted for particulate matter, weather, seasonality, and long-term trends.
The authors state: "... a 10-ppb increase in daily ozone would correspond to an additional 319 annual premature deaths for New York City and 3,767 premature deaths annually for the 95 urban communities, based on mortality data from 2000. This value is probably an underestimate of the total mortality burden from such an increase in ozone because it accounts for only the short-term effects."
They conclude by saying, "Our findings ... indicate that this widespread pollutant adversely affects mortality, in addition to other health effects that have been associated with ozone."
(JAMA. 2004; 292: 2372-2378. Available post-embargo at JAMA.com)
Editor's Note: Funding for authors Bell, Dominici, and McDermott was provided by the U.S. Environmental Protection Agency. Funding for authors Dominici, Samet, and Zeger was also provided by the National Institute for Environmental Health Sciences and by the NIEHS Center in Urban Environmental Health.