This is great evidence to show what I've been telling people here all the time - it's not 'airborne' like say measles or something but it's spread via air - a cough or sneeze will have particles lingering for roughly 3-4 hrs. Just normal breathing is likely to exhale moisture containing the virus, coughing or sneezing will contain much larger droplets with more virii concentration, allowing a faster spread or more likely infection.Report on possible aerosol spread at a choir practice.
I work in the iron and steel industry. Particles of visible steel or iron dust have an obviously much greater weight than that of an invisible virus just about 125nm wide
Just stirring up some dust leaves the particles in the air for quite some time. Transfer points and anywhere the dust can be disturbed leaves the dust in the air for sometimes hours if the air is still.
Make your own conclusions