Ozone pollution is a killer, increasing the yearly risk of death from respiratory diseases by 40% to 50% in heavily polluted cities like Los Angeles and Riverside and by about 25% throughout the rest of the country, researchers reported today. 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. Current standards for ozone pollution cover only eight-hour averages of the colorless gas, but even with that relatively relaxed rule, 345 counties with a total population of more than 100 million people are out of compliance. The Environmental Protection Agency "has already said that it will revisit the current ozone standards in the country," said Dan Greenbaum, president of the Boston-based Health Effects Institute, one of the study's sponsors.