In 2003 the Journal ofthe American Medical Association reported a study examining the possible impact of air pollution caused by the 9/11 attack on New York's World Trade Center on the weight of babies. Researchers found that 8 % of 182 babies born to mothers who were exposed to heavy doses of soot and ash on September 11 were classified as having low birth weight. Only 4 % of 2300 babies born in another New York City hospital whose mothers had not been near the site of the disaster were similar