On Tuesday, the World Health Organization confirmed "emerging evidence" suggesting that the novel coronavirus may be more airborne that was previously understood.

Speaking on Boston Public Radio Wednesday, medical ethicist Art Caplan explained how previously, the official stance from the WHO was that the virus could only travel on large water droplets, “the kind of things that come out of your mouth and nose when you cough and sneeze.”

"I know this is mildly gross,” he admitted.

"Airborne means little droplets can carry the virus. It can piggyback on just about any kind of spray, or anything, and float around. ... I can’t say exactly how far,” he said. "But once it gets airborne, you could be in a room where somebody has been in there and then left, and two hours later it’s still floating around in the air.”

Dr. Benedetta Alleganzi, the WHO's Technical Lead for Infection Prevention and Control and the woman who spoke at Tuesday's briefing, said additional research is needed to be conclusive, and that a more definitive scientific brief is due from the organization in the coming weeks. Their announcement came after significant external pressure from the scientific community on Monday, in the form of an open letter from 239 scientists across 32 countries.

Caplan said Americans ought to take the new research as a cue to keep wearing face masks, even in situations where it might feel excessive.

“It’s really a question of, Can these things take a ride on heavy objects only? Or can they ride around on light little carriers from us?” he said. "And if they do, that means that wearing a mask is really important. Staying six feet apart doesn’t hurt, but you’ve gotta be careful about what rooms you go in and where somebody has been, if they have been infected or they weren’t wearing a mask."

Arthur Caplan is the Drs. William F. and Virginia Connolly Mitty Chair, and the director of the division of medical ethics at the NYU Grossman School of Medicine.