By Kim Painter, USA TODAY
If you pay attention to air quality reports, you may have noticed this: Even on the extra-hot days frying much of the country this summer, "code red" and "code orange" warnings — indicating high levels of ozone pollution — are becoming less common in many cities. Other measures of air quality also have improved greatly, experts say, 40 years after passage of the federal Clean Air Act.
That’s the good news. Here’s the bad: Scientists now believe air pollution is harder on health than once suspected, and that it’s not just lungs that suffer. Hearts, blood vessels and brains do, too.
"We’ve also learned that what we used to think of as fairly low or moderate levels of exposure still has a health impact," says C. Arden Pope, a researcher at Brigham Young University in Provo, Utah.
Bottom line: Better air has saved lives, but air pollution remains a major health problem. That’s one reason the Environmental Protection Agency recently proposed new curbs on power-plant emissions in Eastern states.
Pope was among authors of a new statement on air pollution issued in May by the American Heart Association. It said evidence linking air pollution to heart disease and deaths has "substantially strengthened" since the group’s last review in 2004. The group found:
•Strong links with heart attacks.
•Growing evidence for links to heart failure, stroke, irregular heart beats, cardiac arrest and vascular diseases.
•A "small yet consistent" link between short-term exposure to high pollution levels and death.
"The evidence is quite compelling," Pope says.
While risks to individuals are small and are dwarfed by risk factors such as smoking, high blood pressure and obesity, the overall effect on the public is big, says Robert Brook, a cardiologist at the University of Michigan and lead author of the report.
Much of the worrisome data concerns "fine particulate matter" — tiny bits of soot that come from burning coal, oil, diesel fuel or wood, mostly in factories, vehicles and power plants.
"These fine particles get deep into the lungs," says Norman Edelman, chief medical officer of the American Lung Association. Scientists are not sure what happens next. But the leading theory is that inflammation in the lungs spreads to blood vessels, damages them and makes them more likely to narrow and clog.
It’s also possible that some fine particles seep into blood vessels and the blood itself, causing direct damage. Dirty air also may trigger irregular nervous system activity that affects the heart and blood vessels.
"It’s probably not just one mechanism," Pope says. In any case, he says, science provides a handy example of a similar link: "The most important risk factor for cardiovascular disease is smoking."
Of course, smoking also is very bad for lungs. So is smog and soot. Scientists are learning new details about those links, too. Bad air has long been known to trigger asthma symptoms. Now, studies strongly suggest air pollution may actually cause asthma in some susceptible children, says Stephanie London, a senior investigator at the National Institute of Environmental Health Sciences.
Studies also suggest that lungs may not grow and function as well in children who live, play and attend school in highly polluted areas, she says. That, she says, could affect their lifelong health.
https://www.usatoday.com/news/health/painter/2010-08-09-yourhealth09_ST_N.htmoldId.20100918092049436
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