Just a regular dust mask. I have a half-face respirator, but given that very few people are wearing any mask at all up here despite NY having half of all confirmed cases in the country, folks probably not ready to see a guy walking around with a respirator. Might wear it next trip to Home Depot just to light a fire under the complacent.
Nothing will prevent you from getting infected if you're not careful. But N95 masks, properly worn, provide droplet protection, which is the appropriate level for most. If you're medical staff intubating patients, you need aerosol protection.
But to
@noway2's point, the inoculating dosage matters. If you get a very tiny dose of virus, it may amount to a vaccination, where you get very mildly ill, then get better and now you have antibodies. I suspect variance in inoculating dose size plays a role in why so many young medical staff in Wuhan got severely ill. And probably plays a role in variance we see among otherwise healthy people in general - some get a mild cold, others get a terrible flu that lasts for a couple of weeks, and still others end up on a ventilator. So my guess is anything that reduces potential inoculating dose, even a bandana, is better than nothing.