The results of an 18 year long study published in the NEJM show that even low-levels of ozone exposure cause significant problems among those with respiratory problems.
Motor vehicles are the largest source of ozone pollution.
Here are some snippets from the LA Times story:
Environmental scientists already knew that increases in ozone during periods of heavy pollution caused short-term effects, such as asthma attacks, increased hospitalizations and deaths from heart attacks….But the 18-year study of nearly half a million people, reported today in the New England Journal of Medicine, is the first to show that long-term, low-level exposure to the pollutant can also be lethal.
The researchers found no increase in deaths from cardiovascular disease associated with ozone levels — those deaths are caused primarily by the fine particulates present in air pollution.
They also found no increase in overall mortality, suggesting that ozone is causing deaths in people who were probably going to die in another year or two anyway, according to epidemiologist Joel Schwartz of the Harvard School of Public Health, who was not involved in the study.
“We do know that ozone is particularly dangerous for people living with existing asthma or lung disease,” Jerrett said. And it didn’t matter what someone’s weight, income or education was. “It seems to affect a lot of people relatively equally.”
— Low-level ozone exposure found to be lethal over time, 3/12/2009, The Los Angeles Times.