Southern California children who are exposed to traffic-related air pollution are more likely to develop asthma, according to a study released today by the California Air Resources Board.

An eight-year study of 217 non-asthmatic children from the region found that children who breathed in high amounts of nitrogen dioxide that is found in smog were 30 percent more likely to develop asthma.

"California's prosperity depends on the choice we make to protect our children. This study underlines the need for clean air, giving us the benefits of a fully healthy population," said Mary D. Nichols, chair of the Air Resources Board.

The research from the Southern California Children's Health Study was published in the journal Environmental Health Perspectives.

"Good air quality is fundamental to good health," Nichols said.