A new study suggests that children who grow up within a third of a mile of a freeway may be sustaining permanent respiratory problems.

Researchers studied developing lung function in 1,445 children living in 12 Southern California communities for eight years, from age 10 to 18. They found that the closer the children lived to a freeway, the more likely they were to experience reduced growth in lung function as measured by the standard tests.

"That living near freeways is a health issue is something we've known about for a long time," said Gennet Paauwe, a spokeswoman for the California Air Resources Board, which financed part of the research. "All of this points to the fact that California's air pollution control program needs to continue with its aggressive reduction in air pollutants. But I think this would translate to any other part of the U.S. where people are living near heavily trafficked roadways."

The findings were published online Friday by the British journal Lancet.