Local exposure to traffic on a freeway has serious adverse effects on children’s lung development, which could result in unhealthy lung function in later life, according to an online article published today by The Lancet.

Several studies have shown that lung function in children is affected by urban, regional air pollution and exposure to traffic can result in adverse respiratory effects, including increased rates of asthma and other respiratory diseases. Some studies have shown that lung-function deficiency is related to residential exposure to traffic. However, whether traffic exposure adversely affects lung-function growth during the period of rapid lung development that occurs between the age of 10 and 18 years is unknown. This question is important in view of the established relation between diminished lung function in adulthood and morbidity and mortality rates.

W James Gauderman and colleagues compared lung-function measurements from 3,677 children from 12 southern California communities that represent a wide range in regional air quality. In children who lived within 500 meters of a major road, 8-year lung growth was significantly reduced compared with those who lived 1,500 meters or more from a freeway. The investigators report that both local exposure to freeways and regional air pollution had detrimental, and independent, effects on lung-function growth. There was a pronounced deficit in percentage-predicted lung function at 18 years of age for those living within 500 meters of a freeway.

“In many urban areas, population growth is forcing the construction of housing tracts and schools near to busy roadways, with the result that many children live and attend school in close proximity to major sources of air pollution. . .In view of the magnitude of the reported effects and the importance of lung function as a determinant of adult morbidity and mortality, reduction of exposure to traffic-related air pollutants could lead to substantial public-health benefits,” the authors stated.