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 says. “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 who directed a part of the study. “What this study says is that to protect the public’s health, we cannot just reduce the peaks, we must also reduce long-term, cumulative exposure.”
The new study separates ozone’s effects from those of fine particulate matter, the tiny particles of pollutants emitted by factories, cars, and power plants. By statistically controlling for the other major component of smog - fine particulate matter, particles smaller than 2.5 microns - the researchers were able to tease out the cardiovascular impact of the pollutants and still see ozone’s effects on respiratory health.
The study analysed data on some 450,000 people who were followed from 1982 to 2000. Over that period 118,777 people in the study died. The data, which included cause of death, were linked to air pollution levels in 96 cities using advanced statistical modelling to control for individual risk factors. The researchers estimate that the risk of dying from respiratory causes rises four percent for every ten parts-per-billion increase in exposure to ozone.
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 USA. The city with the highest mean daily maximum ozone concentration over the 18-year period of the study was Riverside (104 ppb). This long-term cumulative exposure corresponded to roughly a 50 percent increased risk of dying from lung disease compared to no exposure to the pollutant. The lowest ozone concentration was seen in San Francisco which had an associated 14 percent increase in risk.
MEDICA.de; Source: New York University Langone Medical Center