March 12, 2009

Ozone Levels Puts Humans At Immediate Risk

Researchers reported on Wednesday, that people who live in areas with the most ozone pollution are 25 to 30 percent more likely to die from lung disease than those living in areas with the cleanest air.

Michael Jerrett, of UC Berkeley, and colleagues studied nearly 500,000 people across the U.S. for 18 years, finding that the ozone played no role in heart disease deaths once air pollution consisting of very tiny particles were taken into account.

However, ozone was the key player in respiratory fatalities.  When at ground level a corrosive form of oxygen is the primary constituent of smog.

"We now know that controlling ozone is not only beneficial for mitigating global warming, but that it could also have near-term benefits in the reduction of deaths from respiratory causes," Jerrett said in a statement.

For every 10 parts-per-billion (ppb) increase in ozone levels, there is a 4 percent in risk of death from respiratory causes, primarily pneumonia and chronic obstructive pulmonary disease, according to the study.

"World Health Organization data indicate that about 240,000 people die each year from respiratory causes in the United States," said Jerrett. "Even a 4 percent increase can translate into thousands of excess deaths each year. Globally, some 7.7 million people die from respiratory causes, so worldwide the impact of ozone pollution could be very large."

The findings come a year after the U.S. Environmental Protection Agency strengthened its National Ambient Air Quality Standards for ground-level ozone from an annual average of 80 to 75 ppb to reflect growing evidence of the harmful health effects of ozone.  A group of leading scientists asked the EPA to issue even stricter health standards for ozone levels, from 60 to 70 ppb.

The findings published in Thursday's New England Journal of Medicine shows that long-term exposure increased mortality, said Jerrett.

"This is the first time we've been able to connect chronic exposure to ozone, one of the most widespread pollutants in the world, with the risk of death," he said.

Doctors have known that ozone is hazardous.  Short-term exposure aggravates asthma symptoms and causes breathing problems.  During hot summer days, ozone alerts are common for many cities in the U.S.


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