Coronavirus-laden particles can persist for up to 30 minutes in an elevator if the doors are kept closed, according to a latest study conducted by the University of Amsterdam.
According to researchers at the University of Amsterdam, aerosols can persist for periods of 10-20 minutes inside an elevator during normal operation while the time frame decreases to just several minutes if the doors are kept open.
The latest study was conducted by a research performed by the UvA Institute of Physics in collaboration with the Amsterdam UMC.
“We found out that during such normal operation, it takes 12 to 18 minutes before the number of aerosol particles decreases by a factor of one hundred. When the elevator doors are permanently open, this time reduces to 2 to 4 minutes,” said Daniel Bonn, one of the study’s lead researchers.
Researchers were able to simulate a series of coughs using a specially designed spray nozzle which they sprayed in a controlled quantity of droplets. To detect the aerosols in the elevator, researchers used a laser to illuminate the aerosol particles and counted them.
Researchers on the study recommend elevator doors be left open for a longer period whenever possible, and for people to either avoid talking and coughing in elevators or wear a proper face mask to avoid transmission.
“It turns out that the ventilation inside all studied elevators in idle position automatically shuts off after 1-2 minutes. This can of course easily be prolonged by reprogramming the action control software,” said Cees van Rijn, the co-researcher on the study.
“In most hospital elevators the ventilator is present in the ceiling and exhausts air from the cabin towards the elevator shaft. A possible measure is reversing the flow direction of the ventilator, creating a downflow of fresh air from the ceiling towards the floor of the elevator cabin,” van Rijn added.