DeCarlo is an associate professor in the College of Engineering and in the College of Arts and Sciences.
Waring is professor and department head for the Department of Civil, Architectural and Environmental Engineering in the College of Engineering.
Most people are aware of the dangers of exposure to second hand smoke. But researchers have found that a surprising quantity of “third-hand” smoke — the lingering chemical residue of tobacco that clings to surfaces long after a cigarette is extinguished — can also be found indoors where there has been no active recent smoking.
“Third-hand smoke, which we are realizing can be as harmful to health as second-hand smoke, is much more difficult to avoid,” says Associate Professor Michael Waring.
Air quality measurements taken from an unoccupied, nonsmoking classroom indicated that almost 30 percent of the particulate matter small enough to be absorbed by the human lung was associated with smoke residue.
To investigate this surprising finding, Waring teamed up with Associate Professor Peter DeCarlo and graduate student Anita Avery to simulate third-hand smoke exposure in a lab. In their controlled test using a closed container, they found a 13 percent increase in third-hand smoke chemical species, which meant that, though it seemed as though the smoke had cleared, a residue remained.
“Aerosol particles are ubiquitous particles suspended in the air — they come from a variety of sources and are known to be detrimental to health,” DeCarlo says. “The fact that third-hand smoke can attach to them, like it would to the clothing or furniture of a smoker, means that the potentially toxic chemicals associated with third-hand smoke are found in places we wouldn’t have expected.”