A box fan, an air filter — and duct tape to attach them.
With four such cobbled together devices, at perhaps a total of $150, the vice-presidential debate on Wednesday night could be made much safer, according to experts in airborne viruses.
Vice President Mike Pence and Senator Kamala Harris will be seated more than 12 feet apart on the podium, with plexiglass barriers between them. Mr. Pence and his aides had objected to the barriers, but relented on Tuesday night.
The barriers might make more sense if Mr. Pence and Ms. Harris were seated more closely together on the podium, scientists said. But the risk in this setting is airborne transmission of the coronavirus, and the barriers will do nothing to protect Ms. Harris and the moderator, Susan Page, Washington bureau chief of USA Today, if Mr. Pence were infected.
On Monday, the Centers for Disease Control and Prevention released new guidelines confirming that the virus can be carried aloft by aerosols — tiny droplets — farther than six feet indoors. In one recent study, scientists isolated infectious virus some 16 feet from an infected patient in a hospital.
Linsey Marr, an expert on airborne viruses at Virginia Tech in Blacksburg, Va., laughed outright when she saw a picture of the debate setup. “It’s absurd,” she said.
When she first heard there would be plexiglass barriers, Dr. Marr said, she had imagined an enclosure with an open back or top: “But these are even smaller and less adequate than I imagined.”
Other experts said the barriers might have made some sense if the debaters were to be seated close together.
“Those plexiglass barriers are really only going to be effective if the vice president or Kamala Harris are spitting at each other,” said Ellie Murray, an epidemiologist at Boston University. “Those are really just splatter shields.”
The C.D.C. on Tuesday cleared Mr. Pence for the debate, saying he had not been in close contact with anyone known to be infected. The agency’s definition of close contact is being within six feet of an infected person for at least 15 minutes.
Yet Mr. Pence said at a rally on Tuesday evening that he had met with President Trump, who last week tested positive for the coronavirus, that morning in the Oval Office.
“What we’ve been seeing over the past week is that there are a lot of spaces in the White House that are pretty enclosed, pretty poorly ventilated, where people can come into close contact even if they are more than six feet away,” Dr. Murray said.
“I would be very surprised if he has not been close enough to some of these people to at least potentially have been infected.”
Mr. Pence has cited multiple negative tests as proof that he is not infected. But tests for the coronavirus may not yield positive results for up to 14 days after exposure to the virus.
Given the risk that Mr. Pence may be infected, experts said, the Commission for