Ozone's Health Impact

LONG-TERM EXPOSURE to ozone, a major pollutant related to the burning of fossil fuels, increases the risk of death from respiratory disease, a new study shows.

In a mammoth analysis of data on 450,000 people in U.S. cities over an 18-year period, a team led by Michael Jerrett of the University of California, Berkeley, School of Public Health found that those who live in areas with high ozone levels, such as Houston or Los Angeles, have a more than 30% greater annual risk of dying from lung disease (N. Engl. J. Med. 2009, 360, 1085).

Previous studies have linked short-term ozone exposure to premature death (C&EN Online Latest News, April 24, 2008). And long-term exposure to particulate pollution has been shown to increase the risk of death from both cardiovascular and respiratory problems. The new study is the first to quantify ozone's long-term health effects.

Stratospheric ozone protects Earth from the sun's ultraviolet radiation, but ground-level ozone—produced by photochemical reactions of ultraviolet light with oxygen and pollutant nitrogen oxides—causes and exacerbates a host of respiratory ailments, including asthma.

"This is an important study that provides key epidemiological evidence of the risk of death from long-term ozone exposure," notes Jonathan I. Levy, a professor in the environmental health department at Harvard School of Public Health who did not participate in the study. The work, he says, indicates "the need to consider the possibility of long-term ozone effects on mortality in regulatory impact analyses."