When hovering seven miles above the earth, ozone is actually beneficial because it blocks ultraviolet radiation from the sun. However, closer to the ground it infiltrates the lungs and may cause damage. A number of studies have tried to link ozone exposure with mortality but they have been inconclusive, the researchers noted.
In their study, Jerrett and his colleagues cross-referenced American Cancer Society data with pollution data from 96 metropolitan areas in the United States. In all, the study included information on almost 449,000 people and included 118,777 deaths occurring over nearly two decades of follow-up.
The results: each additional 10 parts per billion (ppb) of ozone concentration was linked to a 4 percent increase risk of dying from respiratory causes, most notably pneumonia and chronic obstructive pulmonary disease (COPD).
The findings carry the knowledge of air pollution and its effect on health a notch deeper, one expert said.
"This is something we've seen before with high levels of pollution, though we had not identified ozone as something causing respiratory diseases," said Dr. Len Horovitz, a pulmonary specialist with Lenox Hill Hospital in New York City. "We know it's air pollution, but what in air pollution?
Ozone is also a powerful greenhouse gas, Jerrett said, so measures to improve health might have the added benefit of slowing climate change.
"Everybody knows we need to go greener. It's just a question of how we do that," Horovitz stated.
Find out the ozone concentrations in your county at the U.S. Environmental Protection Agency .
SOURCES: Michael Jerrett, Ph.D., associate professor, environmental health sc
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