HealthDay News: Air pollution may slow the normal growth of a developing fetus, a U.S. study has found. Researchers looked at data on nearly 336,000 births in New Jersey between 1999 and 2003 and at daily air pollution readings from across the state. Readings from monitoring sites within six miles of the mothers’ homes were used to calculate average levels of air pollution during their pregnancies. The study found that the risk of a small birth-weight baby increased significantly with each …