Friday, March 13, 2009

Ozone risk worse than once thought

Bad news if you live in polluted megalopolises like Seoul (or Sao Paulo, Los Angeles, etc.): that ozone may be killing you, and not only on days when the ozone levels high.

A longitudinal study released this week in the New England Journal of Medicine (that's the one that DIDN'T print Hwang's findings) says that ozone may be deadlier than once thought. It says that ozone increases the yearly risk of death from respiratory diseases by 40% to 50% in heavily polluted cities (such as Los Angeles) and 25% in other places. These include obstructive pulmonary disease, emphysema, and pneumonia, which account for 8.5% of all deaths in the United States.

Longitudinal studies are often the most thorough in finding the causes and effects of different agents and ailments, but by nature they take a long time. Subjects in this study were tracked for an average of eighteen years.
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.
What may be at work is that people with already chronic respiratory problems are dying one or two years early; The LAT article cites study coauthor Michael Jerrett of UC Berkeley as saying that the findings "could have profound implications because they show that ozone worsens conditions that already kill a large number of people." Furthermore, the constant exposure to ozone itself may be creating higher numbers of such chronically ill people to begin with.

While the Korean government has been making significant strides toward cleaner air (no more yŏnt'an coal bricks, no more Diesel-powered buses, etc.) clearly more needs to be done. The Environmental Protection Agency in the US has already said it will "revisit the current ozone standards in the country," and places like South Korea should follow suit.

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