According to a new study almost a quarter of the people who were exposed to the 9/11 attacks in New York City in 2001 have lung problems most likely due to exposure to dust from the collapsed towers. The problems were about 2.5 times more than would be expected to be seen in people who smoke said study co-author Dr. Jacqueline Moline, director of the World Trade Center Medical Monitoring and Treatment Program Clinical Center.

"These tests confirm what we've seen clinically: People are sick, they're short of breath," Moline said. "They used to run miles a day, now they can barely run the length of a football field." Experts estimate that in the aftermath of the terror attack on the World Trade Center about 40,000 people, including fire and rescue workers, were exposed to noxious pollution.

The study conducted by Mount Sinai Medical Center's medical monitoring program tracked more than 3,160 responders between 2004 and 2007 that had already been tested between the middle of 2002 and 2004. The researchers reported that a little over 24 % of the patients had abnormal lung function and this proves that people exposed to toxic dust suffer from persistent illness. Moline said, "The most common finding we see is that people aren't able to take in as deep of a breath as you'd expect, and some can't push it out as much."

Researchers have not been able to say what this means to their health in the long run. Moline said the normal lung capacity in a similar group of people would be five percent for non-smokers and 10 percent for smokers. Those at the site developed a typical "World Trade Center cough" while many people had itchy eyes and runny noses well after 2006 when the site cleanup had ended.

"These are problems we're seeing five or six or seven years after the towers fell," Moline said. "Many of these folks are going to have long-term problems, and their lung function won't return to normal."

According to research released in September by the New York City health department an estimated 400,000 people were exposed to the disaster including nearby residents and commuters and an estimated 35,000 to 70,000 of them developed post-traumatic stress disorder, and 3,800 to 12,600 people developed asthma as a result.

Dr. Norman Edelman, chief medical officer of the American Lung Association said, "We don't know what it means for future health so we must, as the authors suggest, continue to follow them."

The study appeared in Thursday's editions of CHEST, a journal published by the American College of Chest Physicians.