The cause of death has not been determined, his wife Jean Lioy told the New York Times.
The author of the 2010 published book "Dust: The Inside Story of Its Role in the September 11th Aftermath," Lioy received two lifetime achievement awards -- the Wesolowski Award from the International Society of Exposure Analysis and the Frank Chambers Award from the Air and Waste Management Association.
Lioy was a professor of environmental and occupational health at the Rutgers University School of Public Health, where he specialized in exposure science, according to the university's website.
He was also the deputy director for government relations for the Public Health department at Rutgers University.
In this field, Lioy specialized with the toxins and pollutants that affect both environmental science and occupation health.
After witnessing the dust rising from the ruins of the Twin Towers all the way from his home in Cranford, New Jersey, Lioy became one of the first scientists to gather samples and test the dust from the site.
"It was unprecedented in terms of the complex characteristics of the materials released," Lioy told USA Today
In an interview on the Rutgers website
, Lioy explained his findings: the dust was linked to an array of long-term health concerns, most alarming an unexpected persistent cough experienced by some police officers, residents and firefighters.
"In the first 48 hours, the government was concerned about asbestos being the primary threat," Lioy said. "But it was not. Asbestos exposure is a long-term problem. Once the 'World Trade Center cough' started appearing, we realized it wasn't caused by asbestos."
According to Lioy, three factors caused the cough.
"First, cement dust was very alkaline -- the pH was above 10," he said. "That irritated the linings of the lungs. Second, glass fibers got stuck in people's upper airways, like wooden logs in a narrow stream. That trapped the cement particles and enhanced the irritation. And there were very coarse particles that comprised the vast quantity of the dust mass."
Lioy was born on May 27, 1947, in Passaic, New Jersey. He received a B.A. from Montclair State College in physics and education, an M.S. from Auburn University in Alabama in physics and applied mathematics and a doctoral degree from Rutgers University in environmental science.
He is survived by his wife, Jean, whom he married in 1971; his son, Jason; his mother, also Jean Lioy; his sister, Mary jean Giannini and his two grandchildren.