.jpg)
Researchers from University of California Davis show that even healthy lungs can suffer from ozone levels believed to be safe. Ozone levels deemed safe have been found to have a negative impact on lung function after just a few hours of walking, cycling, or performing light exercise. Decreased lung function from exposure to “safe” ozone levels improved over several hours, but questions remain about what happens after repeatedly being subjected to low level ozone polllutants.
The researchers say new and lower ozone limits are just not enough to protect even healthy lungs. "The National Ambient Air Quality Standard (NAAQS) for ozone was recently revised to set lower limits for ozone concentrations. Specifically, we found that 6.6 hours exposure to mean ozone concentrations as low as 70 parts per billion have a significant negative effect on lung function, even though the current NAAQS standards allow ozone concentrations to be up to 75 parts per billion (ppb) over an eight-hour period”, explains Edward Schelegle, Ph.D., of the University of California Davis.
The scientists say their study highlights the need for more studies, especially among individuals susceptible to ground level smog produced by motor vehicle exhaust, industrial emissions, gasoline fumes, and chemical solvents.
The researchers recruited thirty-one healthy subjects who were non-smokers for the study. Lung function was measured before exposure to varying levels of ozone pollution. The group was asked to answer questions about symptoms before during and after exposure.
During fifty minutes of moderate exercise, the group was subjected to ozone at 60, 70, 80 or 87 ppb or filtered air during the 6.6 hour exercise study. Exercises were performed for fifty minutes at time, followed by ten minute breaks, with a thirty-five minute lunch break between the third and fourth session. After 5.6 hours of being exposed to ozone levels deemed safe, the study participants experienced “significant” declines in lung function.
"These data tells us that even at levels currently below the air quality standard, healthy people may experience decreased lung function after just a few hours of moderate to light exercise such as bicycling or walking," said Dr. Schelegle.
The authors note the incidence of increased hospitalizations when ozone levels are highest. They suggest more studies to understand individual susceptibility to levels believed to be safe. Some individuals in the study displayed a stronger response than others, a finding that needs more investigation. Decreased lung function was worse in association with higher ozone level exposure in the study.
The most significant part of the study is "Understanding how these mechanisms change with repeated daily exposures…especially as ambient ozone levels are often elevated several days in a row," says Dr. Schelegle.
The research shows that lung function decreases from exposure to safe ozone levels, even in healthy individuals. It may be important to pay attention to individual, repeated exposure.
Healthy individuals, and especially anyone with asthma, COPD or other respiratory related illness should remain aware of ozone levels in the area. Even healthy individuals can experience respiratory symptoms and decreased lung function from playing and exercising outdoors too long, even when ozone levels are deemed acceptable. The long-term effects of repeated safe ozone exposure on healthy lungs will need more research.
You can check Charlotte’s ozone levels at: AirNow
Source: American Journal of Respiratory and Critical Care Medicine
You might also enjoy:
Smokers Might Reduce COPD Risk With Soy
Comments