An 18-year study shows that even low-doses of ozone pollution are a killer in heavily polluted cities, such as Los Angeles and Riverside, California.
The study, published in the New England Journal of Medicine, included nearly one half million who were tracked for 18 years. Short- term effects, such as asthma attacks, an increase in heart attacks, and hospitalizations were observed, leading to an increase in the risk of death by 40 to 50 percent.
The report may lead to a revision in the current ozone standards.
Ozone is a colorless gas that originates from the burning of fossil fuels, from chemical solvents, and vehicle exhaust. When nitrogen oxide reacts in the presence of sun and heat, ozone is formed, a known secondary pollutant that reacts with cells linings the lungs.
Premature aging and inflammation can result.
In the study out of the University of California Berkeley, more than 448,000 were included who had enrolled in an American Cancer Society Cancer Prevention Study beginning in 1982. Altogether there were nearly 50,000 deaths, about 20 percent of them from respiratory disease.
The Los Angeles Times reports that there was a four percent increase in dying from respiratory disease with every 10 part per billion increase in ozone.
For example, Riverside had the highest ozone concentration at 104 ppb. The risk of respiratory disease became 50 percent higher than if there was no ozone.
Los Angeles has a 43 percent risk and San Francisco a 14 percent risk with the lowest average ozone level of 33 ppb.
Also low are areas that have cooler weather and rain such as the Pacific Northwest.
In the 51 cities with the cleanest air, the life expectancy increased by nearly five months, according to a study published in January in the The New England Journal of Medicine, the first time that life span was attached to air pollution
Cardiovascular deaths did not seem to fluctuate with varying ozone levels. However, small particles in the air can imbed deeply into the respiratory system when inhaled from polluted air and may trigger a cardiac event or atherosclerosis.
"We do know that ozone is particularly dangerous for people living with existing asthma or lung disease," Coauthor Michael Jerrett of UC Berkeley told the Los Angeles Times. And it didn't matter what someone's weight, income or education was. "It seems to affect a lot of people relatively equally."
The findings show a worsening of conditions that that lead to death, but not an overall change in mortality, said Jerrett, indicating those people were a year or two from dying. #