"Covid precautions have turned many parts of our world into a giant salad bar,
with plastic barriers separating sales clerks from shoppers, dividing customers
at nail salons and shielding students from their classmates.
Intuition tells us a plastic shield would be protective against germs. But
scientists who study aerosols, air flow and ventilation say that much of the
time, the barriers don’t help and probably give people a false sense of
security. And sometimes the barriers can make things worse.
Research suggests that in some instances, a barrier protecting a clerk behind a
checkout counter may redirect the germs to another worker or customer. Rows of
clear plastic shields, like those you might find in a nail salon or classroom,
can also impede normal air flow and ventilation.
Under normal conditions in stores, classrooms and offices, exhaled breath
particles disperse, carried by air currents and, depending on the ventilation
system, are replaced by fresh air roughly every 15 to 30 minutes. But erecting
plastic barriers can change air flow in a room, disrupt normal ventilation and
create “dead zones,” where viral aerosol particles can build up and become
Via Dave Farber.
*** Xanni ***
Chief Scientist, Xanadu
Partner, Glass Wings
Manager, Serious Cybernetics