Because this is actually a fairly well defined area of research. Sneezing absolutely does produce particles that small. Ebola cannot be transmitted by those particles. The larger droplets that can transmit Ebola are too large to make it through a ventilation system.
> Although they are not naturally transmitted by aerosol, they are highly infectious as respirable particles under laboratory conditions.
I think the issue is to what degree it can get into the fluid that is sneezed out by humans... Once it's in it, the size of the droplet does not matter to how viable the virus is - it's deadly if inhaled in by someone else.
