Outdoor Pollution and Lung Function Effects
Experts explain air pollution's impact on health and the steps you can take to protect your lungs.
How do the different types of pollutants in air pollution affect lung function? continued...
But in particular, ozone, particulates and sulfur dioxide "inflame the linings of the lungs," which makes them work harder and can cause heart attack, he says. Sulfur dioxide and ozone react chemically with surfaces inside the lungs, causing inflammation that produces mucus, coughing, and serious breathing trouble.
Perhaps most is known about ozone, which increases susceptibility to respiratory infections and causes flare-ups in people with chronic lung problems and stresses the arteries and heart. Michael Jerrett, PhD, associate professor of environmental health at the University of California-Berkeley, reported in a recent New England Journal of Medicine study that long-term exposure to the sooty gas at ground level increases the risk of death from respiratory problems by more than 30%.
"Our study showed us that ozone is more harmful than we thought," Jerrett tells WebMD.
Among particulate matter, small particulates stay in the lungs longer and get picked up by white blood cells. But the more pollution of any kind, the harder this becomes, which is why the lungs of smokers and people who live in polluted cities are dark gray or black. "There's no way for the body to get the junk out again," Ownby says.
Cherry Wongtrakool, MD, a pulmonary specialist at Emory University, says people with lung problems like asthma and chronic obstructive pulmonary disease are more susceptible than others to ozone and particulate matter, which can result in coughing, wheezing, and shortness of breath. Long-term exposure may lead to atherosclerosis, or hardening of the arteries, she says.
For people who live in cities, it's an ongoing battle, and the lungs gradually lose the ability to clear the pollution and fight back, Ownby says.
Wongtrakool says air pollution not only can worsen lung function in people with breathing problems but also can decrease lung function in those with healthy lungs. Inhaling pollution makes healthy lungs sick over the long term, causing coughing, wheezing, irritation, and dangerous stress on the cardiovascular system.
Are there certain parts of the country where pollution is worse than others?
Without doubt, Jerrett says. He says his recent study examined 18 years' worth of data from 96 metropolitan areas and nearly 450,000 people. The highest concentrations of ozone and highest death rates due to ozone are in southern California; the lowest in the Northwest and parts of the Great Plains. In general, cities in the Northeast had lower ozone than California, though some have dangerously dirty air. People in New York had a 25% increased risk of dying from lung disease, compared to 43% in Los Angeles. Among the most ozone-rich cities were Washington, D.C.; Richmond, Va.; Chattanooga, Tenn.; and Charlotte, N.C. Low concentrations were recorded in places like San Francisco, where dirty air is blown away by ocean winds.