The droplets that are large enough to carry infectious doses of Ebola virus are heavy enough to fall almost immediately, typically within 3 feet. The small droplets that can travel through the air typically dry out very quickly—the Ebola virus does not tolerate being dried out—and are too small to carry infectious doses—some are smaller than the virus.
Influenza and cold viruses are about 1/10 of the size of the smallest Ebola viruses.
So that’s where CDC’s 1 meter rule comes from. Thank you!