Posted Mar 20, 2009
By Thomas H. Maugh II
Los Angeles Times
Ozone pollution is a killer, increasing the yearly risk of death from respiratory diseases by 40 to 50 percent in heavily polluted cities in Southern California and by about 25 percent throughout the rest of the country, researchers said today.
Scientists knew that spikes in ozone during heavy pollution cause short-term effects, such as asthma attacks, hospitalizations and heart attacks.
But the 18-year study of nearly half a million people reported in the New England Journal of Medicine is the first to show that long- term, low-level exposure can be lethal.
Standards for ozone pollution cover only eight-hour averages , but even under that measure, 345 counties with a total population of over 100 million are out of compliance. The Environmental Protection Agency might need an annual standard, said scientist Daniel Krewski of the University of Ottawa, a study co-author .
The findings could have profound implications, said co-author Michael Jerrett of the University of California at Berkeley, because they show that ozone worsens conditions that already kill a lot of people. Worldwide, respiratory problems cause 7.7 million deaths a year.
Ozone is a secondary pollutant, not formed directly by the burning of fossil fuels. Rather, nitrogen oxides produced by burning react in sunlight to form ozone. It reacts with virtually anything it comes in contact with – in particular, cells in the lungs, causing inflammation and other effects that produce premature aging.
Jerrett and his colleagues studied 448,850 people over age 18 in 96 metropolitan regions who enrolled in 1982 and 19 83. The subjects were tracked for an average of 18 years. During that follow-up, there were 48,884 deaths, 9,891 of them from respiratory diseases.
The researchers found that every 10-parts-per-billion increase in average ozone concentrations was associated with about a 4 percent increase in deaths from respiratory causes.
Date: Mar 12, 2009
