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Sept. 27, 2007 -- Lung-threatening smog levels dropped 7% last year in the Eastern U.S., a new government report shows.
The Environmental Protection Agency (EPA) said Thursday that levels of smog, also known as ground-level ozone, continued a six-year declining trend since 2000. Overall, smog pollution in the Eastern U.S. has dropped 60% since the beginning of the decade, the report concludes.
"It's good news for the health of our environment, it's good news for the health of our residents," Stephen L. Johnson, EPA's administrator, told reporters via telephone Thursday.
Smog is caused by nitrogen oxide emissions (mainly from power plants and car tailpipes) that are exposed to sunlight.
The pollution causes inflammation in the lining of the lungs. It is known to worsen the severity of asthma and a host of other lung ailments in both children and adults. Smog is typically worse during the summer.
The report shows declining smog levels in most urban centers in the eastern part of the country. Exceptions are New Orleans, where smog levels continued to rise, and Atlanta, where there was no change.
The report comes as regulators consider tightening federal smog standards. The EPA has proposed lowering allowable smog levels from 84 parts per billion currently allowed to 70-75 parts per billion.
"I will be making a final decision on that health standard by March of next year," Johnson said.
Janice Nolen, an assistant vice president at the American Lung Association, says the agency should drop allowable ozone levels to no more than 60 parts per billion.
The organization points to epidemiologic studies showing potential health effects in otherwise healthy adults at levels between 60 and 70 parts per billion.
"We have a lot of research to show that the levels we thought were safe, which is the current standard, are not safe," Nolen tells WebMD.
Frank O'Donnell, president of Clean Air Watch, an environmental group, called the results encouraging. But he pointed out that at least 40 states and the District of Columbia experienced unsafe ozone levels over the summer.
"We have not solved the smog problem -- not by a long shot," O'Donnell said. "Let's not pop open too many champagne bottles."