Nope. Ebola is not spread through aerosols like measles or influenza is. Ebola is spread through contact with infected bodily fluids (including droplets from, for instance, someone vomiting nearby).
You aren’t in danger from someone who has Ebola and has been in the same room. On the other hand, the mask won’t protect you from splashes of bodily fluid from someone who has Ebola.
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Unless, of course, they sneeze.
Droplet precautions are three feet.
Sneezing is not an Ebola symptom. Typically, they have diarrhea and vomiting; some may cough. Some bleed out. You want to avoid all bodily fluids.
In at least one case, a man gave his wife Ebola weeks after he recovered. I won't explain how.