Computer simulations suggest thermal plumes may trap infectious particles near the head
PORTLAND, Ore. — In small rooms, body heat may draw particles to all the wrong places. Thermal plumes radiating off a person can waft microbes, pollen and dust into breathing range, a study presented March 16 at a meeting of the American Physical Society finds.
Understanding how body heat affects particle motion may help engineers design airflow systems that minimize particle exposure, said study coauthor John McLaughlin of Clarkson University in Potsdam, N.Y.
“One of the conventional ideas about thermal plumes was that hot air rising up over a body will protect you from having particles fall down on top of you,” McLaughlin says. “But in small rooms, it’s exactly the opposite.”
The researchers created a computer simulation of a human form sitting in the middle of a 4.8-square-meter room as 1,000 particles flooded in through an air vent. Particles were 10 micrometers in diameter — the size of some flu-carrying saliva