A [removed]new nationwide study[/removed] reveals that long-term exposure to elevated levels of ground ozone—a major constituent of smog—significantly raises the risk of dying from lung disease. The study, conducted by the NYU Langone Medical Center, evaluated the impact of ozone on respiratory health over an 18-year period in cities across the United States.
Findings show the risk of dying from respiratory disease was more than 30% greater in metropolitan areas with the highest ozone concentrations than in those with the lowest ozone concentrations.
This study is the first nationwide population study on the long-term impact of ozone on human health, and the first to separate ozone’s effects from those of fine particulate matter, the tiny particles of pollutants emitted by factories, cars, and power plants.Over the ten years, numerous nationwide studies have shown that long-term exposure to tiny particles of dust and soot in air pollution is a risk factor for death from heart and lung disease. However, it was unclear whether long-term exposure to ozone, a widespread pollutant in summertime haze, was linked to a higher risk of dying from lung disease itself.
"Many studies have shown that a high-ozone day leads to an increase in risk of acute health effects the next day, for example, asthma attacks and heart attacks," says George D. Thurston, ScD, from the NYU Langone Medical Center in a press release on the study. "What this study says is that to protect the public’s health, we can’t just reduce the peaks, we must also reduce long-term, cumulative exposure."
Ozone data collected between 1977 and 2000 showed that California had both the city with the highest and the city with the lowest concentration of ozone pollution in the country. The researchers estimate that the risk of dying from respiratory causes rises 4% for every 10 parts-per-billion increase in exposure to ozone. Based on this result, Riverside, Calif had the highest mean daily maximum ozone concentration over the 18-year period of the study with 104 ppb. This long-term cumulative exposure corresponded to roughly a 50% increased risk of dying from lung disease compared to no exposure to the pollutant. The lowest ozone concentration was seen in San Francisco (33 ppb long-term average daily maximum), which had an associated 14% increase in risk.
The EPA provides a list of counties in the United States, their present ozone concentrations, and their compliance status with regard to the current short-term ozone standard Online.
The study appears in the March 12 issue of the New England Journal of Medicine.