Even without the launching power of a sneeze, air currents could carry a flow of aerosol sized virus particles exhaled by an infected person 20 feet or more away.

“In any confined geometry like an office room, meeting room, department store, food store,” said Eugene Chudnovsky, a physicist at the City University of New York. In a study not yet peer reviewed, he analyzed air flow and showed how, “the vortices in the air are taking the virus to different places.”

A preliminary study at the University of Nebraska Medical Center found evidence of coronavirus genetic material on various surfaces in isolation rooms where infected patients were being treated, including on air vents more than six feet from the patients. The research, which has not yet been peer reviewed, indicates that the virus can occasionally travel long distances.

“The virus is so small, it can hitch a ride even on tiny, tiny particles,” Dr. Fineberg said. “But how important is each size and how well they can transmit disease is not fully understood.”