In the largest and longest study of its kind, USC researchers have found that children living near busy highways have significant impairments in the development of their lungs that can lead to respiratory problems for the rest of their lives.
The 13-year study of more than 3,600 children in 12 Central and Southern California communities found that the damage from living within 500 yards of a freeway is about the same as that from living in communities with the highest pollution levels, the team reported Thursday in the online version of the medical journal Lancet.
"If you live in a high-pollution area and live near a busy road, you get a doubling" of the damage, said lead author W. James Gauderman, an epidemiologist at the Keck School of Medicine of USC.
"Someone suffering a pollution-related deficit in lung function as a child will probably have less than healthy lungs all of his or her life," he said.
The greatest damage appears to be in the small airways of the lung and is normally associated with the fine particulate matter emitted by automobiles.
"This tells me that I wouldn't want to be raising my children near a significant source of fine-particle air pollution," said economist C. Arden Pope III of Brigham Young University, an expert on air pollution and health who was not involved in the study. "I, myself, would want to be living in areas where the exposure is lower."
The research is part of an ongoing study of the effects of air pollution on children's respiratory health. Previous findings have detailed how smog can stunt lung growth and how living close to freeways can increase the risk of children being diagnosed with asthma.
This latest study of freeway proximity and lung capacity was funded by the California Air Resources Board; the National Institute of Environmental Health Sciences; the Environmental Protection Agency; the National Heart, Lung and Blood Institute; and the Hastings Foundation.
Gauderman and his colleagues recruited groups of fourth-grade students, average age 10, in 1993 and 1996. Their schools were scattered from Atascadero in San Luis Obispo County to Alpine in San Diego County.
The team collected extensive information about each child's home, socioeconomic status and other facts that might impinge on health.
Once each year, the team visited the schools and measured the children's lungs, assessing how much air could be expelled in one breath and how quickly it could be expelled.
