The thing I love (and occasionally hate) about Joe Biden is his tendency to talk off script, as he did this week when he advised commuters to stay out of confined spaces like subways and airplanes.

Although Biden later retracted his statement, according to the National Research Council, seems to be spot-on, at least where airplanes are concerned. From the NRC's manual, " THE AIRLINER CABIN ENVIRONMENT AND THE HEALTH OF PASSENGERS AND CREW" (bolds and caps theirs):

“Coughing and sneezing produce the biologically richest aerosols [i.e. containing the most bacteria and viruses]. A sneeze produces very large droplets (200 microns and larger). Immediately on release, respiratory droplets begin to dry. Many become droplet nuclei, which are very small, remain airborne for long periods, and [...] can remain infective for hours or even days.”

“Filters currently used in aircraft ventilation systems probably remove only a very small fraction of the continually produced bioaerosols.”

“Data from doctors’ offices and schools clearly indicate that viruses can be circulated through ventilation systems, remain viable, and infect people who have no physical contact with the source. In aircraft cabins, this effect might be augmented by the low relative humidity, which would prolong the life of the airborne viruses. “

The available evidence suggests “microbiologic air contaminents” circulate through the cabin and into the cockpit, and concentrations are highest before take off and during descent and landing.

Via Infrastructurist.