ReadersDigestAustraliaNewZealand-April2018

COURTESY LYDIA BOUROUIBA, PHD, MASSACHUSETTS INSTITUTE OF TECHNOLOGY

2

The largest droplets

(illustrated in green)

rocket out of the

sneezer’s mouth and rapidly

plummet under their own

weight within a few seconds.

Average distance travelled:

one to two metres.

3

In the ‘puff phase’

of a sneeze

(illustrated in red),

a turbulent cloud of warm,

moist air swirls through

the air, carrying the

sneeze droplets with it.

4

The cloud grows

and slows as it pulls

in air from the

environment, carrying the

smallest droplets up to

eight metres from their

point of origin.^5

Buoyed by the cloud,

small droplets can

easily stay airborne

long enough to reach

overhead vents (and thus

anywhere in a building).

It’s a big problem. But there’s

a solution an arm’s length

away: coversneezes with a

sleeve or tissue, wash your

hands regularly, and keep

those germs to yourself.

April• 2018 | 73